WO2015033313A2 - Abnormal n-heterocyclic carbene metal complexes, synthesis and processes thereof - Google Patents

Abstract

The present disclosure relates to abnormal N-Heterocyclic Carbene complexes. The 5 present disclosure also relates to synthesis, characterization and applications of abnormal N-Heterocyclic Carbene Complex.

Description

ABNORMAL N-HETEROCYCLIC CARBENE METAL COMPLEXES, SYNTHESIS AND PROCESSES THEREOF"

TECHNICAL FIELD

The present disclosure relates to the field of organometallic chemistry and click chemistry. Specifically, the present disclosure relates to abnormal N-Heterocyclic Carbene (a HC) complexes. The present disclosure also relates to the synthesis, characterization and applications of abnormal N-Heterocyclic Carbene Complexes. BACKGROUND AND PRIOR ART OF THE DISCLOSURE

NHCs are electron-rich, strong neutral donor ligands having reactivities like other classical 2 electron donors such as phosphines, amines, ethers etc. Isolation of normal N-heterocyclic carbenes («NHCs) by Arduengo and co-workers has led to numerous exciting discoveries in organometallic chemistry. The N-heterocyclic carbenes also have been used as nucleophiles for organocatalytic reactions efficiently catalyzing a number of organic transformations. The normal NHCs bind to metal centre through C- 2 carbon atom. In 2001, Crabtree, Faller and co-workers first reported a new mode of NHC binding to a metal ion termed as the abnormal mode of metal binding of NHC through C-4 centre on treatment of 2-pyridylmethylimidazolium salt with IrH₅(PPh₃)2. It is now well documented that the abnormal mode of bonding leads to stronger binding to the metal centre due to its superior strength of σ-donating property that helps in holding the metal centre in the reaction medium. This particular property has great relevance during the catalytic cycle with regard to leaching of the active metal centre during catalysis. However, the isolated abnormal carbenes have long been considered as transient species till the isolation of abnormal N-heterocyclic carbene (aNHC) by Bertrand and co-workers in 2009. The abnormal N-heterocyclic carbene (aNHC) was isolated by chemically blocking the C-2 position and the isolated abnormal NHC was characterized by single crystal X-ray diffraction. This particular report led to the anticipation that the access to this type of abnormal NHC would lead to new cornerstones in the field of organometallic and organocatalysis. Metal coordinated aNHCs have been documented as excellent potential catalysts, for the activation of un-reactive bonds such as C-H and H-H. Further, it has been reported that aNHC coordinated metal complexes have outperformed the catalytic activity as compared to their normal HC counterpart (« HC). Abnormal N-heterocyclic carbene [l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-5-ylidene] can be used very efficiently in metal free ring opening polymerization of three different cyclic esters leading to the development of the best organocatalyst for ring opening polymerization catalysis among any HCs. Further, applications of a HCs were demonstrated to synthesize halobridged C-H activated palladium dimers for Suzuki-Miyaura cross coupling of challenging aryl chloride substrates delivering excellent yield at room temperature under very low-catalyst loading (0.005 mol%). Furthermore, it is known that copper (I) « HCs are well recognized as outstanding catalysts in chemical reactions such as preparation of cyclic compounds. The preparation of cyclic compounds from the click reaction using HC's and their application as ligands for transition metal chemistry have been reported by several research groups. However, the activation of sterically hindered azides and alkynes in click reaction has been limited under solvent free condition and usually requires elevated temperature conditions for progress of the reaction to yield the corresponding product. On the other hand, synthesis of 4,5-disubstituted triazoles can be achieved by using internal alkyne substrates, which usually requires a long time and thermal activation. Thus the activation of sterically hindered azides and alkynes as well as the activation of internal alkyne in click reaction at room temperature, under solvent free condition, within short reaction time has remained among the great challenges in this area. The present disclosure aims at overcoming the aforesaid drawbacks of the prior art. STATEMENT OF THE DISCLOSURE

The present disclosure relates to a compound of formula (I) :

Formula (I)

wherein, Rl is individually selected from a group comprising straight or branched chain alkyl, straight or branched chain alkenyl, straight or branched chainalkynyl, aryl, alkaryl, aralkyl, heteroaryl and heteroaralkyl, wherein each of them is optionally substituted,

M is a metal selected from a group comprising copper, silver, gold, palladium, titanium, chromium, manganese, iron, cobalt, nickel, zinc, zirconium, molybdenum, rhodium, cadmium, osmium, platinum, tin and germanium; and

X is a halide selected from a group comprising chloro, bromo, iodo and fluoro;

A process for preparing compound of formula (I), said process comprising step of reacting a compound of formula (II)

Formula (II) wherein,

Rl is individually selected from a group comprising straight or branched chain alkyl, straight or branched chain alkenyl, straight or branched chainalkynyl, aryl, alkaryl, aralkyl, heteroaryl and heteroaralkyl, wherein each of them is optionally substituted, and

X is a halide selected from a group comprising chloro, bromo, iodo and fluoro. with a compound of formula (III)

MX

Formula (III)

wherein, M is a metal selected from a group comprising copper, silver, gold, palladium, titanium, chromium, manganese, iron, cobalt, nickel, zinc, zirconium, molybdenum, rhodium, cadmium, osmium, platinum, tin and germanium; and X is a halide selected from a group comprising chloro, bromo, fluoro, and iodo, in presence of silyl derivative and solvent; A catalyst system comprising at least one compound of formula (I); a process of activating alkyne functionality or azide functionality, said process comprising step of reacting the alkyne functionality or azide functionality with compound of formula (I); and a process for preparing triazole compounds, said process comprising step of reacting a first reactant having an azide functionality and a second reactant having an alkyne functionality, in presence of compound of formula (I).

BRIEF DESCRIPTION OF ACCOMPANYING FIGURES

In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure where: Figure 1 depicts the perspective Oak Ridge Thermal Ellipsoid Plot (ORTEP) view of the molecular crystal structures of copper halide complexes 1 and 2. Thermal ellipsoids are drawn with 50% probability. Hydrogen atoms and lattice held solvent molecule (dichloromethane) have been omitted for the sake of clarity. Selected bond lengths (in A) and bond angles (°) for 1 : Cul-C5, 1.882(2); Cul-Cll, 2.1031(10); C5-Cul-Cl l, 173.65(6). Selected bond lengths (in A) and bond angles (°) for 2: Cul- C5, 1.901(6); Cul-Cll, 2.043(3); C5-Cul-Cll, 173.9(2). Figure 2 depicts the plot of conversion [%] versus time (t) in the coupling of phenyl acetylene (1.73 mmol) with benzyl azide (1.57 mmol) at 25 °C using catalyst 1 (1 mol %). Figure 3 depicts the longevity of the catalyst 1 which was tested by monitoring the complete consumption of substrates by ^XH NMR spectroscopy in ten consecutive catalytic cycles without adding any additional catalyst into the reaction medium.

Figure 4 depicts the longevity of the catalyst 1 which was tested by monitoring the complete consumption of substrates by 1H NMR spectroscopy in five consecutive catalytic cycles without adding any additional catalyst into the reaction medium.

Figure 5 depicts the ^XH and ¹³C NMR spectra of complex 1. Figure 6 depicts the ^XH and ¹³C NMR spectra of complex 2.

Figure 7 depicts the ^XH NMR spectra of complex 3.

DESCRIPTION OF THE DISCLOSURE

The present disclosure is addressed to the aforementioned needs in the art, and provides a catalyst complex for carrying out a wide variety of organic transformations or reactions. As used herein, the terms "complex", "compound", "catalyst", "metal halide carbene complex", "metal halide aNHC complex" and "aNHC metal halide complex" are employed interchangeably within the instant disclosure.

As used herein, the terms "complex 1", "compound 1", "catalyst 1", "metal halide carbene complex 1", "metal halide aNHC complex 1" and "CuCl-l,3-bis(2,6- diisopropylphenyl)-2,4-diphenyl-imidazolium" are employed interchangeably within the instant disclosure. As used herein, the terms "complex 2", "compound 2", "catalyst 2", "metal halide carbene complex 2", "metal halide a HC complex 2" and "CuBr-l,3-bis(2,6- diisopropylphenyl)-2,4-diphenyl-imidazolium" are employed interchangeably within the instant disclosure.

As used herein, the terms "complex 3", "compound 3", "catalyst 3", "metal halide carbene complex 3", "metal halide aNHC complex 3" and "Cul-l,3-bis(2,6- diisopropylphenyl)-2,4-diphenyl-imidazolium" are employed interchangeably within the instant disclosure.

As used herein, the terms "compound", "derivative", "functionality" and "product" are employed interchangeably within the instant disclosure.

As used herein, the term "room temperature" throughout the specification refers to a temperature ranging from "20 °C to 26 °C".

As used herein, the terms "first," "second," and the like do not denote any order or importance, but rather are used to distinguish one element from another, and the terms "the", "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Furthermore, all ranges reciting the same quantity or physical property are inclusive of the recited endpoints and independently combinable. The modifier "about" used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context or includes the degree of error associated with measurement of the particular quantity.

The present disclosure relates to metal halide aNHC complexes/compounds (1-4) and a process for preparing said complexes/compounds. The metal halide aNHC halide complex/compound is represented by the following formula:

Formula (I) wherein,

Rl is individually selected from a group comprising straight or branched chain alkyl, straight or branched chain alkenyl, straight or branched chainalkynyl, aryl, alkaryl, aralkyl, heteroaryl and heteroaralkyl, wherein each of them is optionally substituted,

M is a metal selected from a group comprising copper, silver, gold, palladium, titanium, chromium, manganese, iron, cobalt, nickel, zinc, zirconium, molybdenum, rhodium, cadmium, osmium, platinum, tin and germanium; and

X is a halide selected from a group comprising chloro, bromo, iodo and fluoro.

In an embodiment of the present disclosure, Rl is aryl which is optionally substituted. In another embodiment of the present disclosure, aryl is "phenyl".

In yet another embodiment of the present disclosure, substituted aryl is and 2,6- dii sopropylphenyl . In another embodiment of the present disclosure, M is a metal copper.

In an embodiment of the present disclosure, the compound of formula I is CuCl-1,3- bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium. In an embodiment of the present disclosure, the compound of formula I is CuBr-1,3- bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In an embodiment of the present disclosure, the compound of formula I is CuI-1,3- bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In an embodiment of the present disclosure, the compound of formula I is CuF-1,3- bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium. The present disclosure also relates to a process for the synthesis and characterization of a HC metal halide complexes using l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl- imidazolium salt. In an embodiment of the present disclosure, the a HC metal halide complex is CuCl- l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In another embodiment of the present disclosure, the a HC metal halide complex is CuBr-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In yet another embodiment of the present disclosure, the a HC metal halide complex is CuI-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In still another embodiment of the present disclosure, the aNHC metal halide complex is CuF-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

The present disclosure relates to a process for preparing compound of formula (I), said process comprising step of reactin a compound of formula (II)

Formula (II) wherein,

Rl is individually selected from a group comprising straight or branched chain alkyl, straight or branched chain alkenyl, straight or branched chainalkynyl, aryl, alkaryl, aralkyl, heteroaryl and heteroaralkyl, wherein each of them is optionally substituted, and

X is a halide selected from a group comprising chloro, bromo, iodo and fluoro.

with a compound of formula (III) MX

M is a metal selected from a group comprising copper, silver, gold, palladium, titanium, chromium, manganese, iron, cobalt, nickel, zinc, zirconium, molybdenum, rhodium, cadmium, osmium, platinum, tin and germanium; and halide selected from a group comprising chloro, bromo, fluoro, and

in presence of silyl derivative and solvent.

In an embodiment of the present disclosure, the silyl derivative is selected from a group comprising potassium bis(trimethylsilyl)amide, lithium bis(trimethylsilyl)amide and combination thereof.

In another embodiment of the present disclosure, the solvent is selected from a group comprising tetrahydrofuran, ether and combination thereof.

In still another embodiment of the present disclosure, the process is carried out at a temperature ranging from about -100 °C to about 50 °C, preferably at a temperature ranging from about -80 °C to about 25 °C and for a time period ranging from about 20 min to about 14 hours, preferably for a time period ranging from about 30 min to about 13 hours.

In an embodiment of the present disclosure, the compound of formula (I) is CuCl-1,3- bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium. In another embodiment of the present disclosure, the compound of formula (I) is CuBr-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In yet another embodiment of the present disclosure, the compound of formula (I) is CuI-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium. In still another embodiment of the present disclosure, the compound of formula (I) is CuF-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium. The present invention also relates to a catalyst system comprising at least one of compounds of formula (I).

In an embodiment of the present disclosure, the catalyst system comprise CuCl-1,3- bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In another embodiment of the present disclosure, the catalyst system comprise CuBr- l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In still another embodiment of the present disclosure, the catalyst system comprise CuI-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium.

In still another embodiment of the present disclosure, the catalyst system comprise CuF-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium. In an embodiment of the present disclosure, a process of activating alkyne functionality or azide functionality, said process comprising step of reacting the alkyne functionality or azide functionality with compound of formula (I) as prepared above. In an embodiment of the present disclosure, a process for preparing triazole compounds, said process comprising step of reacting a first reactant having an azide functionality and a second reactant having an alkyne functionality in presence of compound of formula (I) as prepared above. In an embodiment of the present disclosure, the process of activating alkyne functionality or azide functionality or the process for preparing triazole compounds is carried out at a temperature ranging from about 20 °C to about 70 °C, preferably at a temperature of about 25 °C and for a time period ranging from about 3 minutes to about 10 hours, preferably for a time period ranging from about 5 minutes to about 9 hours.

In yet another embodiment of the present disclosure, the azide functionality is selected from a group comprising aliphatic azide, aryl azide, sterically hindered azides and combinations thereof, wherein each of them is optionally substituted.

In still another embodiment of the present disclosure, the aliphatic azide is selected from a group comprising but not limiting to benzyl azide, 4-bromobenzyl azide, 4- chlorobenzyl azide and 4-fluorobenzyl azide.

In still another embodiment of the present disclosure, the aryl azide is selected from a group comprising but not limiting to phenyl azide, 2,6-dimethyl azide, 2,4,6-trimethyl azide and 2,6-diisopropyl azide.

In still another embodiment of the present disclosure, the sterically hindered azide is selected from a group comprising but not limiting to 2,4,6-trimethyl azide and 2,6- diisopropyl azide. In still another embodiment of the present disclosure, the alkyne functionality is selected from a group comprising electron rich alkynes, electron poor alkynes, sterically hindered alkynes, internal alkynes and combinations thereof, wherein each of them is optionally substituted. In still another embodiment of the present disclosure, the electron rich alkynes is selected from a group comprising but not limiting to phenyl acetylene, 4- methylphenylacetylene, 4-methoxyphenylacetylene, trimethylsilylacetylene, 1- hexyne, 1-octyne, 1-decyne, 3,3-dimethyl-l-butyne, 3 -hydroxy-3 -methyl- 1-butyne, ethynylcyclohexane, 3-aminoprop-l-yne, 2-methylbut-3-yn-2-amine, and combinations thereof.

In still another embodiment of the present disclosure, the electron poor alkyne is not limiting to 4-fluorophenylacetylene, 3-chloroprop-l-yne, 3-bromooprop-l-yne, propiolamide, 2-ethynylpyridine, methyl propiolate, propiolic acid. In still another embodiment of the present disclosure, the sterically hindered alkyne is not limiting to mesitylacetylene, 2,6-diisoproylphenylacetylene. In still another embodiment of the present disclosure, the internal alkyne is selected from a group comprising but not limiting to diphenylacetylene, 3-hexyne, 1-phenyl-l- butyne, dimethyl but-2-ynedioate, diethyl but-2-ynedioate, 1,2-diphenylethyne, but-1- yn-l-ylbenzene, and combinations thereof. In an embodiment of the present disclosure, the imidazolium salt is employed as aNHC precursors to prepare aNHC metal halide complexes. Complexes 1-4 (CuX- [l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium]_J_scheme 1) are prepared by treatment of the aNHC salt (IA) or IB or IC or ID with potassium bis(trimethylsilyl)amide and corresponding metal halide in tetrahydrofuran (THF). After the completion of reaction, the colour of the reaction mixture changes from colourless to green. Analytically pure compound of 1-4 are obtained by recrystallization of the dried reaction mixture from dichloromethane (DCM)/pentane mixture yielding light green colour crystals of 1 in about 70% yield. The complexes 1 and 2 are characterized by NMR spectroscopy (figures 5 and 6), X-ray crystallography and complex 3 is characterized by NMR spectroscopy (figure 7). The 1H NMR spectrum of complex 1 featured the absence of the characteristic singlet at δ 8.8 ppm arising from C5(H) of imidazolium salt, IA confirming the abnormal mode of copper binding. The ¹³C NMR spectrum revealed a singlet peak at δ 159.4 ppm assigned to the C-5 carbon resonance bound to the copper centre for complex 1. This NMR chemical shift value is comparable to that reported with a copper carbene complex CuCl-(TPh) (TPh = 3-methyl-l,4-diphenyl-l,2,3-triazol-5-ylidene) where a metal-bound carbene carbon appeared around δ

IA X=CI 1 X=CI IB X=Br 2 X=Br IC X=I 3 X=I ID X=F 4 X=F wherein M=Cu, Ph=Phenyl.

Scheme 1 Synthetic scheme leading to abnormal N-heterocyclic carbene |^"L3-bis(2,6- diisopropvlphenvl)-2,4-diphenyl-imidazolium1 metal halide complexes 1-.

161.3 ppm in the C MR spectrum. Further, the molecular structure is determined by the X-ray crystallographic study (Figure 1) and the analysis of crystal structure studies confirmed the atom connectivity of 1 and 2 as depicted in Scheme 1. Compounds 1 and 2 are crystallized in the triclinic space group PL The geometry around copper ion is linear exhibiting abnormal mode of HC binding in 1. The Cu-C and the Cu-Cl bond lengths for complex 1 are found to be 1.882(2) A and 2.1031(10) A respectively. The Cu-C and the Cu-Br bond lengths for complex 2 are found to be 1.901(6) A and 2.043(3) A respectively. These values compare well with those observed (1.881(7) A and 2.106(2) A for Cu-C and Cu-Cl, respectively) in a related NHC copper(I) complex, CuCl(IPr) (IPr = l,3-bis(2,6- diisopropylphenyl)imidazol-2- ylidene). The C-Cu-Cl bond angle is determined as 173.65(6)° indicating a nearly linear geometry around the Cu(I) centre in complex 1. The C-Cu-Br bond angle is determined as 173.9(2)° indicating a nearly linear geometry around the Cu center in complex 2.

General procedure for the [3+2] cycloaddition of azides and terminal alkynes

Alkyne (1.73 mmol), azide (1.57 mmol), and compound 1/2/3 (10 mg, 1 mol%) are loaded in a 25 mL Schlenk flask. The reaction mixture is stirred at room temperature (about 25 °C). After appropriate period of time, the reaction is quenched by dissolving the reaction mixture in dichloromethane (10 mL). Subsequently, a simple aqueous workup is carried out by adding 10 mL of water, and the organic layer is extracted with dichloromethane. The water layer is washed twice by adding two 5 mL portions of dichloromethane. The white solid is dried under high vacuum for 12 hours which evaporated the excess volatile alkyne substrate yielding NMR pure isolated product. In case of non-volatile alkyne substrate, the excess alkynes are removed by column chromatographic separation.

General procedure for the [3+2] cycloaddition of sterically hindered azides and sterically hindered alkynes Alkyne (1.73 mmol), azide (1.57 mmol), and compound 1 (10 mg, 1 mol%) are loaded in a 25 mL Schlenk flask. The reaction mixture is stirred at room temperature (about 25 °C). After appropriate period of time, the reaction is quenched by dissolving the reaction mixture in dichloromethane (10 mL). Subsequently, a simple aqueous workup is carried out by adding 10 mL of water and the organic layer is extracted with dichloromethane. The water layer is washed twice by adding two 5 mL portions of dichloromethane. The crude product is purified by flash chromatography on silica gel yielding NMR pure isolated product.

General procedure for the [3+2] cycloaddition of azides and internal alkynes

Alkyne (1.73 mmol), azide (1.57 mmol), and compound 1 (10 mg, 1 mol%) are loaded in a 25 mL Schlenk flask. The reaction mixture is allowed to proceed at room temperature (about 25 °C) or at 70 °C. After appropriate period of time, the reaction is quenched by dissolving the reaction mixture in dichloromethane (10 mL). Subsequently, a simple aqueous workup is carried out by adding 10 mL of water and the organic layer is extracted with dichloromethane. The water layer is washed twice by adding two 5 mL portions of dichloromethane. The crude product is purified by flash chromatography on silica gel yielding NMR pure isolated product.

Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein. However, the examples and the figures should not be construed to limit the scope of the present disclosure. Examples

Example 1: Synthesis of complex 1 fCuCl-[l,3-bisf2,6-diisopropylphenyl)-2,4- diphenyl-imidazoliuml

Under an argon atmosphere, THF (10 mL tetrahydrofuran) is added at -78 °C to a mixture of l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium salt IA (308 mg, 0.50 mmol), copper(I) chloride (50 mg, 0.5 mmol) and potassium bis(trimethylsilyl) amide (200 mg, 1 mmol). After 30 min at -78 °C, the mixture is warmed to room temperature and stirred for 12 h. Solvent is evaporated under reduced pressure and the residue is extracted with dichloromethane (3 x 20 mL). The analytically pure light green title compound (complex 1) is obtained (224 mg, 0.35 mmol, 70 %) by recrystallization from CH₂Cl₂/pentane.

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.49-7.40 (m, 4H), 7.21-7.18 (m, 8H), 7.05 (t, J= 8 Hz, 2H), 6.85 (d, J = 7.5 Hz, 2H), 2.68-2.63(m, 2H), 2.58-2.54 (m, 2H), 1.41 (d, J = 7 Hz, 6H), 0.95 (d, J = 7 Hz, 6H), 0.80 ( t, J = 6.8 Hz, 12H) ppm. ¹³C NMR (125 MHz, 25 °C, TMS): δ 159.4, 144.9, 144.5, 144.4, 141.6, 135.7, 131.1, 130.9, 130.5, 130.4, 130.3, 129.4, 129, 128.2, 128.1, 127.9, 125.2, 124.5, 123.5, 28.8, 28.6, 25.8, 23.7, 23.4, 22.5 ppm. HR-MS: m/z=639.256, calcd. for C₃₉H₄₅ClCuN₂ [M+H]⁺: 639.258 Example 2: Synthesis of complex 2 fCuBr-[l,3-bisf2,6-diisopropylphenyl)-2,4- diphenyl-imidazoliuml

Under an argon atmosphere, THF (10 mL tetrahydrofuran) is added at -78 °C to a mixture of l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium salt IB (308 mg, 0.50 mmol), copper(I) bromide (72 mg, 0.5 mmol) and potassium bis(trimethylsilyl)amide (200 mg, 1 mmol). After 30 min at -78 °C, the mixture is warmed to room temperature and stirred for 12 h. Solvent is evaporated under reduced pressure and the residue is extracted with dichloromethane (3 x 20 mL). The analytically pure light green title compound (complex 2) was obtained (240 mg, 0.41 mmol, 70 %) by recrystallization from CH₂Cl₂/pentane.

1H NMR (400 MHz, CDC1₃ 25 °C, TMS): δ 7.5 (t, J = 8 Hz, 1H), 7.4 (t, J = 8 Hz, 1H), 7.35-7.28 (m, 8H), 7.16 (d, J = 8.4 Hz, 2H), 7.07 (t, J = 8 Hz, 2H), 6.85 (d, J = 7.6 Hz, 2H), 2.45-2.38(m, 2H), 2.37-2.30 (m, 2H), 1.35 (d, J = 6.9 Hz, 6H), 0.85 (d, J = 6.9 Hz, 6H), 0.77 ( t, J = 6.1 Hz, 12H) ppm. ¹³C NMR (100 MHz, DMSO-d₆, 25 °C) δ (ppm): 154.8, 146.9, 144.9, 114.5, 138.7, 133.1, 132.7, 132.5, 130.9, 130.7, 129.3, 129, 128.7, 128.4, 126, 125.9, 124.8, 120.6, 28.6, 28.2, 24.5, 23.8, 23.3, 22.8.

Example 3: Synthesis of complex 3 (^uI-[l,3-bis(2,6-diisopropylphenyl)-2,4- diphenyl-imidazoliuml

Under an argon atmosphere, THF (10 mL tetrahydrofuran) is added at -78 °C to a mixture of l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium salt IC (308 mg, 0.50 mmol), copper(I) iodide (95 mg, 0.5 mmol) and potassium bis(trimethylsilyl)amide (200 mg, 1 mmol). After 30 min at -78 °C, the mixture is warmed to room temperature and stirred for 12 h. Solvent is evaporated under reduced pressure and the residue is extracted with dichloromethane (3 x 20 mL). The analytically pure light green title compound is obtained (255 mg, 0.35 mmol, 70 %) by recrystallization from CH₂Cl₂/pentane.

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.62 (t, J = 8.4 Hz, 1H), 7.54 (t, J = 7.6 Hz, 1H), 7.40-7.34 (m, 8H), 7.22 (d, J = 8.4 Hz, 2H), 7.14 (t, J = 8.4 Hz, 2H), 6.90 (d, J = 7.6 Hz, 2H), 2.49-2.42(m, 2H), 2.42-2.35 (m, 2H), 1.40 (d, J = 6 Hz, 6H), 0.90 (d, J = 6.9 Hz, 6H), 0.83 ( t, J = 6.1 Hz, 12H) ppm.

Figures 5, 6 and 7 depict the spectral characterisation details of the complexes 1, 2 and 3 respectively.

Example 4:

To develop aNHC metal halide complex as catalyst for different organic transformations, the catalytic activity of complex 1 is evaluated for the click reaction of benzyl azide with phenylacetylene without adding any solvent. The reaction went on smoothly leading to quantitative conversion into product 4a (Figure 2). The progress of the reaction is monitored by 1H NMR spectroscopy which reveals that within first 15 minutes, the reaction reaches to completion (Figure 2). In a control experiment, the catalytic reaction is carried out maintaining identical reaction condition using CuCl as catalyst (loading 1 mol%) under solvent free condition with benzyl azide and phenylacetylene as substrates. Even after 60 min, CuCl produced only a trace amount of 4a (less than 5%), an observation noted in earlier studies. Further, the scope of the reaction is investigated by carrying out reactions of benzyl azide and 4-bromo benzyl azide with a variety of alkynes using 1 mol% of catalyst 1 under solvent free condition and the results of the catalytic reactions are summarized in Table 1. The reactions are carried out at room temperature in the absence of solvent with a catalyst loading of 1.0 mol%. During the catalysis under solvent free condition, the initial liquid reaction mixture solidifies after the consumption of substrates. The analytically pure product is isolated as a solid material after initial workup with dichloromethane/water. The results presented in Table 1 establish that the catalyst 1 is very active in the click reaction. It successfully applies for both electron-rich as well as electron-poor alkynes. Also the catalyst has sufficient functional group tolerance as indicated in the case of products summarized in table 1 (4c, 4d, 4g, 4h, 4o, 4r, 4s, 4t, and 4u).

Table 1. Solvent free route to triazoles by click chemistry using catalyst 1 and aliphatic azide as substrate. ^[a]

Entry Azide Alkyne Product Time Yield¹*¹ (%)

7 R¹ = Br R² = OMe 4g 30 min 98

8 R¹ = Br R² = F 4h 10 min 98

9 R^{1 =} H n = 2 4i 45 min 98

10 R^{1 =} H n = 4 4j 45 min 98

11 R^{1 =} H n = 6 4k 45 min 98

12 R¹ = Br n = 2 41 lh 98

13 R¹ = Br n = 4 4m lh 98

19 R^{1 =} H R² = Me 4s 2h 96 20 R¹ = Br R ² = H 4t 3h 96

21 R¹ = Br R ² = Me 4u 3h 96

n

22 R¹ = H 4v 45 min 99

23 R¹ = Br 4w lh 97

24 R¹ = H R² = C1 4x 5 h 75

25 R¹ = H R² = Br 4y 5 h 73

26 R¹ = H R² = NH₂ 4z 4 h 98

II

27 R¹ = H R² = NH₂ 4aa 2 h 93

28 R¹ = H R² = OMe 4ab 15 min 97

29 R¹ = H R² = OH 4ac 15 min 83

{

30 R¹ = H 4ad 3 h 96

31 R¹ = H 4ae 5 h 93

l ^|Reaction conditions: azide (1.57 mmol), alkyne (1.73 mmol), catalyst 1 (1.0 mol%), 25 °C. ^{[ I}Isolated yield after initial workup with dichloromethane/water.

Cycloaddition with phenylacetylene as well as with electron deficient fluoro substituted phenylacetylene proceeded smoothly to give the corresponding 1,2,3- triazoles in quantitative yield in short period of time (4a, 4d, 4e, and 4h; Table 1 within 30 min). The reactions are comparatively slow (reaction completion time 45 min - 2 h) for electron-rich alkynes such as alkyl substituted alkynes and trimethylsilylacetylene (4i, 4j, 4k, 41, 4m, 4n, 4o, 4p, 4v and 4w; Table 1). Functional groups such as different hydroxyl groups were tolerated (4r, 4s, 4t and 4u; Table 1) during the reaction, however the reaction required relatively longer reaction time (2-3 h).

Table 2. Solvent free route to triazoles by click chemistry using catalyst 1 and aryl azide as substrate. ^[a]

Entr Azide Alkyne Product Time Yield¹⁰¹ (%)

1 R¹ = R² = R³ = H R⁴ = H 6a 10 min 98

2 R¹ = R² = R³ = H R⁴ = Me 6b 15 min 98

3 R¹ = R² = Me, R³ = H R⁴ = H 6c 6h 94

4 R¹ = R² = Me, R³ = H R⁴ = Me 6(1 7h 95

5 R¹ = R² = Me,R³ = H R⁴ = F 6e 7h 93

6 R¹ = R² = R³ = Me R⁴ = H 6f 5h 95

7 R¹ = R² = R³ = Me R⁴ = Me 6g 6h 91

8 R¹ = R² = R³ = Me R⁴ = F 6h 6h 92

10 R¹ = R² = R³ = H 6j lh 94

11 R¹ = R² = Me, R³ = H 6k 9h 91

12 R¹ = R² = R³ = Me 61 8h 92

'Reaction conditions: azide (1.57 mmol), alkyne (1.73 mmol), catalyst 1 (1.0 mol%), 25 °C. 'isolated yield after initial workup with dichloromethane/water.

To investigate the scope of this catalytic system to activate electron rich as well as electron poor alkynes, reactions are carried out in the presence of aryl azides instead of aliphatic azides, the results for which are presented in Table 2. All reactions proceeded smoothly to completion within short reaction time and the triazoles (6a-61) are isolated in excellent yield with high purity after workup with dichloromethane/water. Table 2 showcases that in the presence of catalyst 1, phenylazides react and yield the triazole products (6a, 6b, 6i and 6j) in very short reaction time. The reactions are comparatively slow for sterically crowded azides such as 2,6-dimethylazide (6c, 6d, 6e and 6k; Table 2) and mesitylazide (6f, 6g, 6h and 61; Table 2) substrates. These results prompted to carry out the reactions of sterically hindered alkynes with sterically hindered azides using catalyst 1, the results of which are shown in scheme 2. Generally, for such challenging sterically hindered substrates, reaction conditions require tert-BuOH/water and stoichiometric amount of CuS0₄/sodium ascorbate to prepare the triazole 9a by the reaction of mesitylacetylene with mesitylazide employing sharpless conditions. Fukuzawa and co-workers have shown that the catalytic reaction using 3 mol% copper(I) l,2,3-triazol-5-ylidene complex gave 9a in 71% yield in 30 min at 100 °C under neat condition and yielded 9b in 63% yield in 18 h at 100 °C under solvent free condition.

9a, 5 h, 95% 9b, 24 h, 78% wherein R1 ,R2,R3=Methyl (9a)

R1 ,R2=2,6-diisoproyl phenyl, R3=H (9b)

Scheme 2. Reaction of sterically hindered alkynes with sterically hindered azides to form triazole in the presence of catalyst 1. Reaction conditions: azide (1.57 mmol), alkyne (1.73 mmol). catalyst 1 (1.0 mol%). 25 °C.

Here, the reaction using only 1 mol% of catalyst 1 took about 5 h at room temperature under solvent free condition to yield 9a in about 95% yield and about 24 h at room temperature under solvent free condition to yield 9b in about 78% yield. This result clearly supports that the present catalyst (catalyst 1) is more active than reported catalysts in cyclizing the sterically hindered challenging substrates at ambient temperature. The high activity of catalyst 1 in the Huisgen cycloaddition prompted to test its reactivity with more challenging internal alkyne substrates. Although several copper catalysts are being used regularly to carry out click reaction using the terminal alkynes but only few studies have been reported for activation of internal alkynes leading to the 4,5- substituted triazole. In a preliminary experiment, treatment of dimethyl acetyl enedi car boxylate or diethyl acetyl enedi carboxy late with phenyl or benzyl azide in the presence of about 1 mol% catalyst 1 yielded the corresponding triazole (12a, 12b, and 12c) in good yield within short reaction time under solvent free condition at room temperature. Reactions using less activated alkyne substrates (diphenylacetylene, 1 -phenyl- 1- butyne, 3-hexyne) using 1 mol% of catalyst 1 led to the formation of triazoles (12d, 12e, and 12f) in fair to good yields after heating at about 70°C temperature. The reaction using diphenylacetylene was complete within 5 h but for other two internal alkyne substrates, reaction took about 24 h to obtain better yield. In case of unsymmetrical internal alkynes, a mixture of two isomers in 2: 1 ratio (12g and 12g as well as 12h and 12h^') are obtained. Nolan and co-workers have earlier shown that the reaction using 5 mol% [(SEVIes)CuBr] (SIMes = N,N'-bis(2,4,6-trimethylphenyl)-4,5- dihydro-imidazol-2-ylidene) as catalyst for 48 h at 70°C under neat condition gave 12e in 80% yield. In the present disclosure, catalyst 1(1 mol %) is loaded in a lesser amount to obtain similar yield of 12e (80%) at about 70°C under solvent free condition in a much lesser time (in 24 h).

No solvent

1 0 n = 0, 1 1 1 1 2

Ph. ,|\U Ph

N N N Ph-N N

Me0₂C C0₂Me Et0₂C C0₂Et Me0₂C C0₂Me Ph Ph

12a, 1 h, 98 % 1 2b, 1 h, 97 % 1 2c, 45 m in , 97 % 12d, 5 h, 85 %

12e , 24 h , 80 % 12f, 24 h, 82 % 12g i 2g'

24 h, 82 %, ( 2 :1 , 12g : 12g" )

12h 1 2h"

24 h, 84 %, ( 2 :1 , 1 2h : 12h" )

Scheme 3. Reaction of azides with internal alkynes to form 4,5 disubstituted triazoles in the presence of catalyst 1. Reaction conditions: azide (1.57 mmol), alkyne (1.73 mmol), catalyst 1 (1.0 mol%).

Example 5:

Procedure for catalyst longevity experiment between benzyl azide and phenyl acetylene

In a Schlenk flask, the compound 1 (10 mg, 1 mol %), phenyl acetylene (1.73 mmol) and benzyl azide (1.57 mmol) are taken and stirred at 25 °C. The reaction mixture is monitored by 1H NMR spectroscopy by taking aliquots of the reaction mixture after 40 minutes interval and the reaction is stopped as the consumption of substrates was complete. During this period, a solid product is formed. Again a fresh batch of liquid substrates phenyl acetylene (1.73 mmol) and benzyl azide (1.57 mmol) are added for the next catalytic cycle without adding any further catalyst into the reaction vessel. This procedure is repeated for a total of ten consecutive catalytic runs. Procedure for catalyst longevity experiment between phenyl azide and phenyl acetylene

In a Schlenk flask, the compound 1 (10 mg, 1 mol %), phenyl acetylene (1.73 mmol) and phenyl azide (1.57 mmol) are taken and stirred at 25 °C. The reaction mixture is monitored by 1H NMR spectroscopy by taking aliquots of the reaction mixture after 30 minutes interval and the reaction is stopped as the consumption of substrates was complete. During this period, a solid product is formed. Again a fresh batch of liquid substrates phenylacetylene (1.73 mmol) and phenyl azide (1.57 mmol) are added for the next catalytic cycle without adding any further catalyst in to the reaction vessel. This procedure is repeated for a total of ten consecutive catalytic runs.

Procedure for catalyst longevity experiment between mesitylazide and mesitylacetylene

In a Schlenk flask, the compound 1 (10 mg, 1 mol %), mesitylacetylene (1.73 mmol) and mesitylazide (1.57 mmol) are taken and stirred at 25 °C. The reaction mixture is monitored by 1H NMR spectroscopy after taking aliquots of the reaction mixture after each 9 h interval and the reaction is stopped as the consumption of substrates was complete. During this period, a solid product is formed. Again a fresh batch of liquid substrates mesitylacetylene (1.73 mmol) and mesitylazide (1.57 mmol) are added for the next catalytic cycle without adding any further catalyst in to the reaction vessel. This procedure is repeated for a total of five consecutive catalytic runs (Figure 4).

It is observed that there is no decomposition of the catalysts or precipitation of metallic copper from catalyst 1 during all the reactions. The stability of the catalytically active species is subjected to further investigation by performing the in situ recycling experiments. One of the major problems in homogeneous catalysis is that catalyst's recycling inability as they are inseparable from the reaction mixture. Earlier attempts by Fukuzawa, Li, Sarkar and co-workers have shown that the activity of copper(I) NHC catalysts in click reaction gradually decreases as the number of catalytic cycles increase and beyond six cycles the catalysts were not tested. Herein, the longevity of the catalyst 1 is assessed by performing several catalytic runs into the same reaction pot to check whether the catalyst remains live for several catalytic cycles. The longevity studies are performed till 10 successive catalytic runs by using 1 mol% of catalyst loading. Although the reaction requires only 20 min for first cycle to consume the substrates of benzyl azide and phenyl acetylene but the reaction took little more time (40 min) for the completion of reaction after sixth cycle which may be attributed to the fact that the solid product on addition of fresh liquid substrate takes some time to become homogeneous reaction mixture. To avoid this problem, the longevity test of catalyst 1 is carried out for benzyl azide and phenyl acetylene by adding a fresh batch of substrates (benzyl azide and phenyl acetylene) after every 40 min interval instead of 20 min without adding any additional catalyst into the reaction vessel. After each 40 min interval, the consumption of substrates is checked by recording 1H MR spectrum of the reaction mixture. The 1H MR spectrum indicated a complete consumption of substrates within 40 min time for 10 successive catalytic runs at about 25 °C. This result clearly demonstrates that the catalyst 1 stays active for 10 catalytic cycles (Figure 3, black colour). After 10 successive cycles, the overall isolated yield of l-benzyl-4-phenyl-l,2,3-triazole (4a) is about 99%. Next, 10 successive catalytic runs are performed by using 1 mol% of catalyst to activate phenyl azide and phenyl acetylene under solvent free condition at room temperature. Although the reaction requires only 10 min for the first catalytic cycle to consume the substrates of phenyl azide and phenyl acetylene but each catalytic cycle is continued for about 30 min to make sure that the additional time is utilized for dissolving the solidified product into the fresh liquid substrate without adding any additional catalyst into the reaction vessel. After each 30 min interval, the consumption of substrates was checked by recording 1H NMR spectrum of the reaction mixture. The 1H NMR spectra indicated a complete consumption of substrates for 10 successive catalytic runs within 30 min time at about 25 °C. This result clearly demonstrates that the catalyst 1 stays active for 10 catalytic cycles (Figure 3, red colour) in this case also establishing the generality of the long life time of the catalyst in the reaction medium. After 10 successive cycles, the overall isolated yield of l,4-diphenyl-lH-l,2,3- triazole (6a) is 96%. This result also prompted to check the longevity of the catalyst in case of click reaction between sterically hindered alkynes with sterically hindered azides. The reaction is carried out to perform 5 successive catalytic runs by using 1 mol% of catalyst 1 to activate mesitylacetylene and mesitylazide under solvent free condition at room temperature. The longevity test of catalyst 1 is carried out for mesitylacetylene and mesitylazide by adding a fresh batch of substrates (mesitylacetylene and mesitylazide) after every 9 h interval without adding any additional catalyst into the reaction vessel.

The ^XH NMR spectrum indicated a complete consumption of substrates for 5 successive catalytic runs within 9 h time at about 25°C. After 5 successive cycles, the overall isolated yield of l,4-dimesityl-lH-l,2,3-triazole (9a) is about 88%. This result clearly demonstrates that the catalyst 1 stays active for 5 catalytic cycles towards mesitylacetylene and mesitylazide. This sustained catalytic activity in consecutive catalytic runs prompted to check the catalyst's ability to execute the click reaction under lower catalyst loading. The lower catalyst loading test is performed using benzyl azide and phenylacetylene as substrates under solvent free condition at room temperature and the results of which are provided in Table 3.

Table 3. Click reactions of benzyl azide and phenylacetylene using catalyst 1 at different loading.

Entry Catalyst (mol %) Time (min.) Υίε1ά^Μ(%) TON

1 0.50 30 99 198

2 0.25 45 99 396

3 0.10 60 99 990

4 0.01 180 99 9900

5 0.005 240 99 19800

'Reaction conditions: azide (1.57 mmol), alkyne (1.73 mmol), catalyst 1 (1.0 mol%), 25 "C.^Isolated yield after initial workup with dichloromethane/water.

The result in Table 3 indicates that the catalyst 1 is active for coupling of benzyl azide and phenylacetylene with as low catalyst loading as 0.005 mol% resulting in a nearly quantitative yield of the product at room temperature which leads to a high TON value of 19800 (Table 3). Example 6:

Catalytic reactions with CuBr-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium (complex 2) and CuI-l,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-imidazolium (Complex 3):

The catalytic activity of complexes 2 and 3 are evaluated for the click reaction of benzyl azide with phenyl acetylene without adding any solvent. The reaction went on smoothly leading to quantitative conversion into products as tabulated in Table 4 below.

6c 6f

Table 4: Click reactions of phenyl azide and phenylacetylene using catalysts 2 and 3. Entry Azide Catalyst Triazole, time, yield

1 3a 2 6a, 10 min, 99%

2 3a 3 6a, 10 min, 99%

3 3b 2 6c, 6 h, 99%

4 3b 3 6c, 6 h, 99%

5 3c 2 6f, 4 h, 99%

6 3c 3 6f, 4 h, 99%

[a] Reaction Condition: Phenylacetylene (0.17 mmol), azide (0.15 mmol), compound 2/3 (1 mg, 1 mol%), 10 min-6 h, 25 °C [b] Isolated yield after chromatography. Thus, the present disclosure describes a synthetic route to a series of metal halide a HC complexes along with the characterization details of the complexes. Complex 1 showed catalytic activity for the Huisgen cycloaddition of azides and alkynes at room temperature to produce triazole compounds. This catalysis can be performed under solvent free condition leading to a green route to a variety of pure triazoles dealing with minimal workup (after catalysis) within short reaction time. Aromatic, electron rich, electron deficient and different functionalized alkynes as well as aromatic azides are tolerated by this catalytic protocol resulting in quantitative yield of the triazole compounds. The catalyst exhibits its activity at very low catalyst loading of about 0.005 mol% at room temperature resulting in high turnover number (TON) value of 19800. The catalyst remains live for 10 successive catalytic runs indicating its long lifetime during catalytic cycle. This longevity of catalyst highlights the strong metal binding ability of aNHC ligand to the copper ion preventing any leaching during catalysis. The catalyst successfully catalyzes the reaction between sterically hindered azides and sterically hindered alkynes under solvent free condition at ambient temperature. Furthermore, the catalyst exhibits efficacy for the more challenging internal alkyne substrates demonstrating its utility in click chemistry for versatile substrates.

Characterization data for Huisgen 1,3-dipolar cycloaddition reaction product 4a (l-benzyl-4-phenyl-l,2,3-triazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.80 (d, J = 9.2 Hz, 2H), 7.66 ( s, 1H), 7.42-7.30 (m, 8H), 5.58 (s, 2H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 148.2, 134.6, 130.3, 129.1, 128.8, 128.7, 128.2, 128.0, 125.7, 119.6, 54.2 ppm.

4b (l-benz l-4-/ olyl- 1 ,2,3-tr iazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 1 '.62 (d, J = 8.6 Hz, 2H), 7.56 (s, 1H), 7.33-7.30(m, 3H), 7.25-7.32 (m, 1H), 7.19 (s, 1H), 7.14 (d, J = 7.9 Hz, 2H), 5.50 (s, 2H), 2.29 (s, 3H) ppm. ¹³C NMR (125 MHz, CDCI₃ 25 °C, TMS): δ 148.3, 138, 134.6, 129.3, 129, 128.6, 128, 127.6, 125.5, 119.3, 54.1, 21.1 ppm.

4c (l-benzyl-4-/7-methoxyphenyl-l,2,3-triazole) 1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.74 (d, J = 8.6 Hz, 2H), 7.60 (bs, 1H), 7.41-7.37

(m, 3H), 7.32-7.30 (m, 2H), 6.93 (d, J = 8.5 Hz, 2H), 5.57 (s, 2H), 3.83 (s, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 159.5, 148.6, 134.7, 129, 128.6, 128,

126.9, 123.3, 119.1, 114.1, 55.2, 54.1 ppm.

4d [l-benzyl-4-(4-fluorophenyl)-l,2,3-triazole]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.78-7.67 (m, 3H), 7.42-7.37 (m, 3H), 7.32-7.31 (m, 2H), 7.10 (t, J= 8.5 Hz, 2H), 5.58 (s, 2H) ppm. ¹³C NMR (125 MHz, CDCI_3, 25 °C, TMS): δ 163.5, 161.5, 147.2, 134.5, 129, 128.7, 127.9, 127.3, 127.2, 126.8, 126.7, 119.3, 115.7, 115.5, 54.1 ppm.

4e [l-(4-bromobenzyl)-4-phenyl-l,2,3-triazole]

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.80 (d, J = 7.3 Hz, 2H), 7.68 (bs, 1H), 7.52 (d, J = 4.9 Hz, 2H), 7.41 (t, J= 7.7 Hz, 2H), 7.33 (t, J= 7.3 Hz, 1H), 7.19 (d, J = 8.6 Hz, 2H), 5.54 (s, 2H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 148.3, 133.7, 132.2, 130.3, 129.6, 128.8, 128.2, 125.7, 122.9, 119.5, 53.4 ppm.

4f [l-(4-bromobenzyl)-4-/ olyl-l,2,3-triazole]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 1.13 (bs, 3H), 7.51 (d, J = 8 Hz, 2H), 7.26-7.18 ( m, 4H), 5.52 (s, 2H), 2.37 (s, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 148.4, 138.1, 133.8, 132.2, 129.6, 129.5, 127.5, 125.6, 122.8, 119.1, 53.4, 21.2 ppm.

4g [l-(4- romobenzyl)-4-(4-methoxyphenyl)-l,2,3-triazole]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.73 (d, J = 8.5 Hz, 2H), 7.61 (bs, 1H), 7.51 (d, J

8.5 Hz, 2H), 7.18 (d, J = 8.5 Hz, 2H), 6.93 (d, J = 8.5 Hz, 2H), 5.51 (s, 2H), 3.83 (s, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 159.6, 149.2, 133.7, 132.2, 129.6, 127, 123, 122.8, 119.2, 114.2, 55.3, 53.5 ppm. HRMS: calcd for Ci₆Hi₅BrN₃0 [M + H]⁺ 344.038, found 344.036.

4h [l-(4-bromobenzyl)-4-(4-fluorophenyl)l,2,3-triazole]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.42-7.39 (m, 2H), 7.16 (d, J = 8.5 Hz, 2H), 6.9 (s, 1H), 6.83 (d, J = 8.5 Hz, 2H), 6.74 (t, J = 8.5 Hz, 2H), 5.17 (s, 2H) ppm. 1³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 163.6, 161.7, 147.5, 133.6, 132.3, 129.6, 127.4, 127.3, 126.6, 123, 119.2, 115.9, 115.7, 53.5 ppm. HRMS: calcd for Ci₅Hi₂BrFN₃ [M + H]⁺ 332.018, found 332.019.

4i (l-benz l-4-butyl-l,2,3-triazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.35-7.33 (m, 3H), 7.24-7.23 (m, 2H), 7.16 (s, 1H), 5.47 (s, 2H), 2.68-2.64 (m, 2H), 1.62-1.58 (m, 2H), 1.36-1.33 (m, 2H), 0.89 (t, J= 7.3 Hz, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 149, 135, 129, 128.5, 127.9, 120.4, 54, 31.5, 25.4, 22.3, 13.7 ppm.

4j (l-benzyl-4-hexyl-l,2,3-triazole)

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.37-7.34 (m, 3H), 7.26-7.24 (m, 3H), 5.50 (s, 2H), 2.69 (bs, 2H), 1.65 (bs, 2H), 1.34-1.25 (m, 6H), 0.86 (t, J = 7 Hz, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 149.1, 134.9, 129, 128.5, 127.9, 120.6, 54.1, 31.4, 29.2, 28.8, 25.6, 22.5, 14 ppm.

4k (l-benzyl-4-octyl- 1 ,2,3-triazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.40-7.33 (m, 3H), 7.27-7.24 (m, 2H), 7.18 (s, 1H), 5.47 (s, 2H), 2.68 (t, J = 7.6 Hz, 2H), 1.78-1.61 (m, 2H), 1.27-1.25 (m, 10H), 0.87 (t, J = 7 Hz, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 149.3, 134.8, 128.9, 128.5, 127.8, 120.8, 54.2, 31.7, 29.6, 29.2, 29.1, 29, 25.7, 22.6, 14 ppm.

41 [l-(4-bromobenzyl)-4-butyl-l,2,3-triazole]

1H MR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.49 (d, J = 7.5 Hz, 3H), 7.11 (d, J = 7.5 Hz, 2H), 5.50 (s, 2H), 2.69 (bs, 2H), 1.73 (bs, 2H), 1.40 (bs, 2H), 0.94 (bs, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 149.8, 133.9, 132.1, 129.5, 122.6, 121.1, 53.5, 31.2, 25.3, 22.2, 13.7 ppm. HRMS: calcd for Ci₃Hi₇BrN₃ [M + H]⁺ 294.058, found 294.057.

4m [l-(4-bromobenzyl)-4-hexyl-l,2,3-triazole]

1H NMR (500 MHz, CDC1_3; 25 °C, TMS): δ 7.49 (d, J = 7.5 Hz, 3H), 7.11 (d, J = 8 Hz, 2H), 5.47 (s, 2H), 2.68 (bs, 2H), 1.68 (bs, 2H), 1.29-1.28 (m, 6H), 0.87 (t, J= 6.5 Hz, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 150, 133.9, 132, 129.5, 122.6, 120.8, 53.5, 31.4, 29, 28.8, 25.6, 22.4, 13.9 ppm. HRMS: calcd for Ci₅H₂iBrN₃ [M + H]⁺ 322.088, found 322.087. 4n [l-(4-bromobenz l)-4-octyl-l,2,3-triazole]

1H NMR (500 MHz, CDC1₃ 25 °C, TMS): δ 7.50 (d, J = 8 Hz, 3H), 7.12 (d, J = 8 Hz, 2H), 5.46 (s, 2H), 2.69 (bs, 2H), 1.67 (bs, 2H), 1.27-1.25 (m, 10H), 0.87 (t, J= 7 Hz, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 150, 134, 132.2, 129.6, 122.7, 120.7, 53.5, 31.8, 29.5, 29.3, 29.2, 29.1, 25.7, 22.6, 14 ppm. HRMS: calcd for Ci₇H₂₅BrN₃ [M + H]⁺ 350.128, found 350.126.

4o (l-benzyl-4-trimethylsilyl-l,2,3-triazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.35 (s, 1H), 7.26-7.15 (m, 5H), 5.45 (s,

2H), 0.19 (s, 9H) ppm. ^ijC NMR (125 MHz, CDC1₃ 25 °C, TMS): δ 147.5, 134.8, 128.9, 128.5, 128, 126.1, 53.5, 0.9 ppm.

4p (l-benz l-4-terf-butyl-l,2,3-triazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.31-7.29 (m, 3H), 7.21-7.18 (m, 2H), 7.12 (s, 1H), 5.42 (s, 2H), 1.25 (s, 9H) ppm. ¹³C NMR (125 MHz, CDC1₃ 25 °C, TMS): δ 158.1, 135, 129, 128.5, 128, 118.3, 53.9, 30.7, 30.3 ppm.

4q [l-(4-bromobenzyl)-4-terf-butyl-l,2,3-triazole]

1H NMR (500 MHz, CDCI_3, 25 °C, TMS): δ 7.49 (t, J = 7.5 Hz, 2H), 7.19 (d, J = 8.5 Hz, 1H),

7.14(d, J = 8 Hz, 2H), 5.52 (s, 2H), 0.32 (s, 9H) ppm. ¹³C NMR (125 MHz, CDC1₃ 25 °C, TMS): δ 158.2, 134, 132.1, 129.6, 122.6, 118.3, 53.1, 30.7, 30.2 ppm. HRMS: calcd for Ci₃Hi₇BrN₃ [M + H]⁺ 294.058, found 294.059.

4r [l-(l-benzyl-l,2,3-triazol-4-yl)ethanol]

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.40 (bs, 1H), 7.29-7.28 (m, 3H), 7.21- 7.20 (m, 2H), 5.43 (s, 2H), 5.00-4.98 (m, 1H), 2.60 (bs, 1H), 1.48 (d, J = 6.1 Hz, 3H) ppm. ¹³C NMR (125 MHz, CDC1₃ 25 °C, TMS): δ 153.1, 134.5, 129, 128.6, 128, 120.5, 62.7, 54.1, 23 ppm 4s [2-(l-benzyl-l,2,3-triazol-4-yl)propan-2-ol]

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.38 (bs, 1H), 7.31-7.25 (m, 3H), 7.21- 7.19 (m, 2H), 5.41 (s, 2H), 2.84 (bs, 1H), 1.54 (s, 6H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 156, 134.6, 129, 128.6, 128.1, 119, 68.4, 54, 30.4 ppm.

4t [l-(l-(4-bromobenzyl)-l,2,3-triazol-4-yl)ethanol]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.50 (d, J = 8 Hz, 3H), 7.15 (d, J = 8.5 Hz, 2H), 5.46 (s, 2H), 5.08 (bs, 1H), 2.43 (bs, 1H), 1.57 -1.56 (m, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 154.3, 133.6, 132.3, 129.8, 122.9, 121.2, 62.8, 53.6, 23.2 ppm. HRMS: calcd for CnHi₃BrN₃0 [M + H]⁺ 282.028, found 282.026.

4u [2-(l- -bromobenzyl)-l,2,3-triazol-4-yl)propan-2-ol]

1H NMR (500 MHz, CDC1₃ 25 °C, TMS): δ 7.50 (d, J = 7.5 Hz, 3H), 7.14 (d, J = 8.5 Hz, 2H), 5.44 (s, 2H), 2.62 (bs, 1H), 1.70 (s, 6H) ppm. ¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 156.2, 133.6,

132.2, 129.7, 122.8, 119.1, 68.5, 53.3, 30.4 ppm. HRMS: calcd for Ci₂Hi₅BrN₃0 [M + H]⁺ 296.038, found 296.036.

4v (l-benzyl-4-cyclohexyl-l,2,3-triazole)

1H NMR (400 MHz, CDC1_3; 25 °C, TMS): δ 7.35-7.34 (m, 4H), 7.24-7.23 (m, 1H), 7.13 (s, 1H), 5.48 (s, 2H), 2.73-2.71 (m, 1H), 2.02-2.00 (m, 2H), 1.76-1.74 (m, 4H), 1.37-1.32 (m, 4H) ppm.¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 154.1, 135, 129, 128.5, 128, 119.1, 53.9, 35.3, 33, 26.1, 26 ppm.

4w [l-(4-bromobenzyl)-4-cyclohexyl-l,2,3-triazole]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.52-7.49 (m, 3H), 7.12 (d, J = 8.5 Hz, 2H), 5.44 (s, 2H), 2.78 (bs, 1H), 2.06 (bs, 2H), 1.78-1.70 (m, 4H), 1.39 (bs, 4H) ppm. 1³C MR (125 MHz, CDC1_3, 25 °C, TMS): δ 155.9, 134, 132.1, 129.6, 122.6, 119.6, 53.3, 35.3, 32.9, 26, 25.9 ppm. HRMS: calcd for Ci₅Hi₉BrN₃ [M + H]⁺ 320.078, found 320.076.

4x [l-benzyl-4-(chloromethyl)-lH-l,2,3-triazole]

1H MR (400 MHz, CDC1₃, 25 °C, TMS): δ 7.54 (s, 1H), 7.37-7.28 (m, 5H), 5.53 (s, 2H), 4.68 (s, 2H) ppm. ¹³C NMR (100 MHz, CDC1₃, 25 °C, TMS): δ 144.6, 134.1, 129.3, 129, 128, 122.7, 54.2, 36.1 ppm. 4y [l-benzyl-4-(bromomethyl)-lH-l,2,3-triazole]

1H NMR (400 MHz, CDC1₃, 25 °C, TMS): δ 7.61 (s, 1H), 7.39-7.35 (m, 5H), 5.55 (s, 2H), 4.67 (s, 2H) ppm. ¹³C NMR (100 MHz, CDC1₃, 25 °C, TMS): δ 144.8, 137.6, 130, 129.6, 128.8, 123.2, 57.8, 22.5 ppm.

4z [(l-benzyl-lH-l,2,3-triazol-4-yl)methanamine hydrochloride]

1H NMR (400 MHz, D₂0, 25 °C, TMS): δ 8.09 (s, 1H), 7.40-7.33 (m, 5H), 5.61 (s, 2H), 4.27 (s, 2H) ppm. ¹³C NMR (100 MHz, D₂0, 25 °C, TMS): δ 140.1, 134.7, 129.1, 128.8, 128.1, 125.5, 54.2, 34 ppm.

4aa [l-benzyl-lH-l,2,3-triazole-4-carboxamide]

1H NMR (400 MHz, DMSO-i¾, 25 °C, TMS): δ 8.59 (s, 1H), 7.86 (s, 1H), 7.47 (s, 1H), 7.39-7.32 (m, 5H), 5.63 (s, 2H) ppm. ¹³C NMR (125 MHz, DMSO-i¾, 25 °C, TMS): δ 161.4, 143.1, 135.7, 128.8, 128.2, 128, 126.6, 53 ppm. HRMS: calcd for Ci₀HioN₄ONa [M + Na]⁺ 225.086, found 225.087. 4ab [methyl l-benzyl-lH-l,2,3-triazole-4-carboxylate]

1H NMR (400 MHz, CDC1₃, 25 °C, TMS): δ 8.07 (bs, 1H), 7.39-7.37 (m, 2H), 7.28- 7.24 (m, 3H), 5.59 (s, 2H), 3.93 (s, 3H) ppm. ¹³C NMR (125 MHz, CDC1₃, 25 °C, TMS): δ 160.9, 140, 133.6, 129.1, 128.9, 128.1, 127.3, 54.2, 51.9 ppm.

4ac [l-benzyl-lH-l,2,3-triazole-4-carboxylic acid]

1H NMR (400 MHz, DMSO-i¾, 25 °C, TMS): δ 8.75 (s, 1H), 7.39-7.33 (m, 5H), 5.64 (s, 2H) ppm. ¹³C NMR (125 MHz, DMSO- , 25 °C, TMS): δ 161.6, 139.9, 135.6, 129, 128.8, 128.3, 128, 53 ppm. 4ad [2-(l-benzyl-lH-l,2,3-triazol-4-yl)pyridine]

1H NMR (400 MHz, CDC1₃, 25 °C, TMS): δ 8.53-8.48 (m, 1H), 8.13-8.07 (m, 2H), 7.74 (s, 1H), 7.34-7.25 (m, 4H), 7.20 (s, 1H), 5.53 (s, 2H) ppm. ¹³C NMR (125 MHz, CDCI₃, 25 °C, TMS): δ 150.1, 149.2, 148.6, 136.8, 134.3, 129, 128.7, 128.2, 122.8, 121.9, 120.1, 54.3 ppm.

4ae [2-(l-benzyl-lH-l,2,3-triazol-4-yl)propan-2-amine]

1H NMR (400 MHz, CDC1₃, 25 °C, TMS): δ 7.40-7.25 (m, 6H), 5.46 (s, 2H), 2.29 (bs, 2H), 1.67 (s, 6H) ppm. ¹³C NMR (100 MHz, CDC1₃, 25 °C, TMS): δ 157.4, 134.4, 128.7, 128.3, 127.8, 119, 54, 51.9, 28.9 ppm.

6a (l,4-diphenyl-lH-l,2,3-triazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 8.21(s, 1H), 7.92 (d, J = 7.9 Hz, 2H), 7.80 (d, J = 7.3 Hz, 2H), 7.55 (t, J = 8 Hz, 2H), 7.48- 7.45 (m, 3H), 7.39- 7.33 (m, 1H) ppm. ¹³C NMR (100 MHz, CDC1_3, 25 °C, TMS): δ 148.4, 137.0, 130.2, 129.8, 128.9, 128.7, 128.4, 125.8, 120.5, 117.6 ppm.

6b (l-phenyl-4-p-tolyl-lH-l,2,3-triazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 8.12 (s, 1H), 7.75 (t, J = 9.1 Hz, 4H), 7.48 (t, J = 8 Hz, 2H), 7.39 (t, J₇ = 7.2 Hz, 1H), 7.21 (d, J = 7.6 Hz, 2H), 2.35 (s, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 148.5, 138.3, 137.1, 129.7, 129.6, 128.6, 127.4, 125.7, 120.5, 117.2, 21.3 ppm. HRMS: calcd for C15H14N3 [M + H]⁺ 236.118, found 236.119.

6c [l-(2,6-dimethylphenyl)-4-phenyl-lH-l,2,3-triazole]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.94 (dd, Ji = 1 Hz, J₂ = 7 Hz, 2H), 7.87 (s, 1H),

7.47 (t, J= 7.5 Hz, 2 H), 7.37 ( t, J = 7.5 Hz, 1H), 7.33 (d, J = 7.5 Hz, 1H), 7.20 (d, J = 8 Hz, 2H), 2.06 (s, 6H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 147.6, 135.9, 135.4, 130.4, 130.0, 128.9, 128.4, 128.3, 125.7, 121.3, 17.4 ppm. HRMS: calcd for C16H16N3 [M + H]⁺ 250.138, found 250.137.

6d [l-(2,6-dimethylphenyl)-4-p-tolyl-lH-l,2,3-triazole]

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.76 (d, J = 7.3 Hz, 3H), 7.22 (t, J = 7.6 Hz, 1H), 7.16 (d, J = 7.9 Hz, 2H), 7.08 (d, J = 7.3 Hz, 2H), 2.29 (s, 3H), 1.94 (s, 6H) ppm. ¹³C NMR (100 MHz, CDC1_3, 25 °C, TMS): δ 147.3, 137.7, 135.6, 135.0, 129.7, 129.3, 128.1, 127.3, 125.3, 120.8, 21.0, 17.0 ppm. HRMS: calcd for Ci₇Hi₈N₃ [M + H]⁺ 264.148, found 264.149.

6e [l-(2,6-dimethylphenyl)-4-(4-fluorophenyl)-lH-l,2,3-triazole]

1H NMR (500 MHz, CDC1_3; 25 °C, TMS): δ 7.91-7.88 (m, 2H), 7.85 (s, 1H), 7.33 (t, J = 7.5 Hz, 1H), 7.19 (d, J= 7.5 Hz, 2H), 7.14 (t, J= 8.5 Hz, 2H), 2.04 (s, 6H) ppm. ¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 163.6, 161.9, 146.7, 135.8, 135.3, 130.0, 128.4, 127.5, 127.4, 126.6, 121.0, 116.0, 115.7, 17.3 ppm. HRMS: calcd for Ci₆Hi₅ FN₃ [M + H]⁺ 268.128, found 268.127.

-mesityl-4-phenyl- 1H- 1 ,2,3-triazole]

1H NMR (400 MHz, CDC1_3; 25 °C, TMS): δ 7.94 (d, J = 6.9 Hz, 2H), 7.85 (s, 1H), 7.45 (t, J = 7.6 Hz, 2H), 7.35 (t, J = 6.6 Hz, 1H), 7.01 (s, 2H), 2.37 (s, 3H), 2.01 (s, 6H) ppm. ¹³C NMR (100 MHz, CDC1_3; 25 °C, TMS): δ 147.4, 139.9, 134.9, 133.4, 130.4, 129.0, 128.8, 128.1, 125.6, 121.4, 21.0, 17.1 ppm. HRMS: calcd for Ci₇Hi₈ N₃ [M + H]⁺ 264.148, found 264.147.

-mesityl-4-p-tolyl-lH-l,2,3-triazole]

1H NMR (500 MHz, CDC1₃ 25 °C, TMS): δ 8.31 (t, J = 7.5 Hz, 3H), 7.76 (d, J = 7.5 Hz, 2H), 7.5 (s, 2H), 2.89 (s, 3H), 2.86 (s, 3H), 2.51 (s, 6H) ppm. ¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 147.5, 139.9, 138.0, 135.0, 133.5, 129.5, 129.0, 127.6, 125.6, 121.1, 21.2, 21.0, 17.2 ppm. HRMS: calcd for Ci₈H₂₀ N₃ [M + H]⁺ 278.168, found 278.169. 6h [4-(4-fluorophenyl)-l-mesityl-lH-l,2,3-triazole]

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.91- 7.87 (m, 2H), 7.84 - 7.83(m, 1H), 7.12 (t, J = 8.9 Hz, 2H), 6.99 (s, 2H), 2.35 (s, 3H), 1.99 (s, 6H) ppm. ¹³C NMR (100 MHz, CDCI_3, 25 °C, TMS): δ 163.8, 161.3, 146.6, 140.0, 134.9, 133.3, 129.0, 127.4, 127.3, 126.6, 121.2, 115.8, 115.6, 21.0, 17.2 ppm. HRMS: calcd for Ci₇Hi₇F N₃ [M + H]⁺ 282.138, found 282.139.

6i [l-phenyl-4-(trimethylsilyl)-lH-l,2,3-triazole]

1H NMR (500 MHz, CDCI_3, 25 °C, TMS): δ 7.95 (s, 1H), 7.72 (d, J = 8 Hz, 2H), 7.49 (t, J = 7.3 Hz, 2H), 7.41- 7.38 (m, 1H), 0.37 (s, 9H) ppm. ¹³C NMR (125 MHz, CDCI₃ 25 °C, TMS): δ 147.3, 137.0, 129.6, 128.4, 127.1, 120.7, 1.0 ppm. HRMS: calcd for CnHi₆N₃Si [M + H]⁺ 218.108, found 218.109. 6j -yl)propan-2-ol]

1H

TMS): δ 7.98 (s, 1H), 7.65 (d, J = 8 Hz, 2H), 7.43 (t, J = 6.8 Hz, 1H), 3.74 (bs, 1H), 1.67 (s, 6H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 156.5, 137.0, 129.5, 128.5, 120.3, 117.8, 68.4, 30.4 ppm. HRMS: calcd for CnHi₃ N₃ONa [M + Na]⁺ 226.100, found 226.101. 6k [2-(l-(2,6-dimethylphenyl)-lH-l,2,3-triazol-4-yl)propan-2-ol]

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7.53 (s, 1H), 7.29 (t, J = 7.6 Hz, 1H), 7.15 (d, J= 7.6 Hz, 2H), 2.91 (bs, 1H), 1.98 (s, 6H), 1.71 (s, 6H) ppm. ¹³C NMR (100 MHz, CDCI₃ 25 °C, TMS): δ 155.6, 135.42, 135.40, 129.9, 128.4, 120.8, 68.6, 30.6, 17.3 ppm. HRMS: calcd for Ci₃Hi₇N₃ONa [M + Na]⁺ 254.137, found 254.138. 61 [2-(l-mesityl-lH-l,2,3-triazol-4-yl)propan-2-ol]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.50 (s, 1H), 6.95 (s, 2H), 3.08 (bs, 1H), 2.33 (s, 3H), 1.92 (s, 6H), 1.69 (s, 6H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 155.5, 139.9, 135.0, 133.5, 128.9, 121.0, 68.6, 30.5, 21.0, 17.1 ppm. HRMS: calcd for Ci₄Hi₉N₃ONa [M + Na]⁺ 268.153, found 268.152.

9a [l,4-dimesityl-lH-l,2,3-triazole]

1H NMR (400 MHz, CDC1_3; 25 °C, TMS): δ 7.47 (s, 1H), 7.03 (s, 2H), 6.98 (s, 2H), 2.38 (s, 3H), 2.31 (s, 3H), 2.19 (s, 6H), 2.05 (s, 6H) ppm. ¹³C NMR (100 MHz, CDC1_3; 25 °C, TMS): δ 145.2, 139.8, 138.0, 137.6, 134.9, 134.8, 133.4, 129.0, 128.2, 127.0, 124.4, 21.0, 20.5, 17.1 ppm.

Eluent: Hexane: Ethyl acetate = 100:2

9b [l,4-bis 2,6-diisopropylphenyl)-lH-l,2,3-triazole]

1H NMR (500 MHz, CDC1_3; 25 °C, TMS): δ 7 ^'.57 (s, 1H), 7.52 (t, J = 8.3 Hz, 1H), 7.43 (t, J = 7.8 Ηζ, ΙΗ), 7.33 (d, J = 8 Hz, 2H), 7.27 (d, J = 8 Hz, 2H), 2.82 (sept, J = 7 Hz, 2H), 2.44 (sept, J = 7 Hz, 2H), 1.25 (d, J = 7 Hz, 6H), 1.17 (d, J = 7 Hz, 12H), 1.14 (d, J = 7 Hz, 6H) ppm. ¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 148.7, 146.0, 144.5, 133.3, 130.8, 129.4, 127.7, 126.3, 123.8, 122.6, 30.53, 29.7, 28.5, 24.3, 23.9, 23.7 ppm. Eluent: Hexane: Ethyl acetate = 100:2

12a (dimethyl l-benzyl-lH-l,2,3-triazole-4,5-dicarboxylate)

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 136-133 (m, 3H), 7.28-7.26 (m, 2H), 5.82 (s, 2H), 3.97 (s, 3H), 3.89 (s, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 160.3, 158.7, 140.1, 133.8, 129.7, 128.8, 128.7, 127.9, 53.8, 53.2, 52.5 ppm. HRMS: calcd for Ci₃Hi₃N₃0₄Na [M + Na]⁺ 298.080, found 298.081.

12b [diethyl l-benzyl-lH-l,2,3-triazole-4,5-dicarboxylate]

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.28-7.26 (m, 3H), 7.22-7.21 (m, 2H), 5.76 (s, 2H), 4.38 (q, J = 7.5 Hz, 2H), 4.29 (q, J = 7.3 Hz, 2H), 1.36 (t, J = 7Hz, 3H), 1.23 (t, J = 7 Hz, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 159.6, 158.0, 139.8, 133.7, 129.5, 128.4, 128.2, 127.5, 62.4, 61.3, 53.3, 13.6, 13.3 ppm. HRMS: calcd for Ci5Hi₇N₃0₄Na [M + Na]⁺ 326.110, found 326.111.

12c (dimethyl l-phenyl-lH-l,2,3-triazole-4,5-dicarboxylate)

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): δ 7.57- 7.53 (m, 5H), 4.00 (s, 1H), 3.91 (s, 3H) ppm. ¹³C NMR (100 MHz, CDC1_3, 25 °C, TMS): δ 160.2, 159.4, 138.7, 135.5, 132.5, 130.5, 129.6, 124.3, 53.8, 52.7 ppm. HRMS: calcd for Ci₂HnN₃0₄Na [M + Na]⁺ 284.060, found 284.061.

12d (l,4,5-triphenyl-lH-l,2,3-triazole)

1H NMR (500 MHz, CDC1_3; 25 °C, TMS): δ 7.62- 7.60 (m, 2H), 7.42- 7.36 (m, 6H), 7.35- 7.29 (m, 5H), 7.22- 7.20 (m, 2H) ppm. ¹³C NMR (125 MHz, CDC1_3; 25 °C, TMS): δ 144.8, 136.5, 133.7, 130.8, 130.2, 129.4, 129.1, 129.0, 128.9, 128.5, 127.9, 127.7, 127.4, 125.2 ppm. Eluent: Hexane: Ethyl acetate = 100:2

12e (l-benzyl-4,5-diethyl-lH-l,2,3-triazole)

1H NMR (400 MHz, CDC1_3, 25 °C, TMS): δ 7 ^'.32- 7.26 (m, 3H), 7.13 (d, J = 6.1 Hz, 2H), 5.45 (s, 2H), 2.63 (q, J = 7.6 Hz, 2H), 2.51 (q, J = 7.6 Hz, 2H), 1.26 (t, J= 7.6 Hz, 3H), 0.94 (t, J = 7.6 Hz, 3H) ppm. ¹³C NMR (100 MHz, CDC1₃ 25 °C, TMS): δ 146.1, 135.3, 133.9, 128.7, 128.0, 126.9, 51.6, 18.3, 15.7, 14.0, 13.1 ppm. Eluent: Hexane: Ethyl acetate = 100:2

12f (4,5-diethyl-l-phenyl-lH-l,2,3-triazole)

1H NMR (500 MHz, CDC1₃ 25 °C, TMS): δ 7.47-7.44 (m, 3H), 7.37- 7.36(m, 2H), 2.68 (q, J = 7.5 Hz, 2H), 2.62 (q, J = 7.5 Hz, 2H), 1.3 (t, J = 7.5 Hz, 3H), 0.99 (t, J = 7.5 Hz, 3H) ppm. ¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS): δ 145.8, 136.7, 134.7, 129.2, 129.16, 125.2, 18.3, 16.0, 14.0, 13.4 ppm. HRMS: calcd for Ci₂Hi₆N₃ [M + H]⁺ 202.138, found 202.139.

Eluent: Hexane: Ethyl acetate = 100:2

Mixture of 12g (l-benzyl-5-ethyl-4-phenyl-lH-l,2,3-triazole) and 12g (1-benzyl- 4-ethyl-5-phenyl-lH-l,2,3-triazole) (2:1)

12g

12g (l-benzyl-5-ethyl-4-phenyl-lH-l,2,3-triazole) 1H NMR (500 MHz, CDCI_3, 25 °C, TMS): δ 7.71 (dd, Ji = 1.5 Hz, J₂ = 8.5 Hz, Ph), 7.44- 7.40 (m, Ph), 7.35- 7.28 (m, Ph), 7.23- 7.19 (m, Ph), 7.12- 7.11 (m, Ph), 7.01- 6.99 (m, Ph), 5.55 (s, benzyl CH₂), 2.76 (q, J= 7.7 Hz, CH₂), 1.04 (t, J= 7.8 Hz, CH₃) ppm. (The signals of phenyl

of 12g overlap with 12g ). 12g (l-benzyl-4-ethyl-5-phenyl-lH-l,2,3-triazole)

1H NMR (500 MHz, CDC1_3, 25 °C, TMS): (5 7.71 (dd, Ji = 1.5 Hz, J₂ = 8.5 Hz, Ph), 7.44- 7.40 (m, Ph), 7.35- 7.28 (m, Ph), 7.23- 7.19 (m, Ph), 7.12- 7.11 (m, Ph), 7.01- 6.99 (m, Ph), 5.39 (s, benzyl CH₂), 2.65 (q, J= 7.5 Hz, CH₂), 1.22 (t, J= 7.8 Hz, CH₃) ppm. (The signals of phenyl of 12g overlap with 12g ).

¹³C NMR (125 MHz, CDC1_3, 25 °C, TMS) (Mixture of 12g and 12g^'): δ 147.0, 144.4, 135.5, 135.2, 134.6, 134.0, 131.6, 129.6, 129.1, 128.9, 128.7, 128.6, 128.5, 128.2, 127.9, 127.6, 127.4, 127.3, 127.0, 126.9, 51.8, 18.5, 18.4, 14.0, 12.9 ppm. (The signals of 12g are too weak to distinguish from 12g^'). HRMS: calcd for Ci₇H_i8N₃ [M + H]⁺ 264.148, found 264.147.

Eluent: Hexane: Ethyl acetate = 100:2 Mixture of 12h (5-ethyl-l,4-diphenyl-lH-l,2,3-triazole) and 12h (4-ethyl-l,5- diphenyl- 1H- 1 ,2,3-triazole) (2:1)

12h (5-ethyl-l ,4-diphenyl- 1H- 1 ,2,3-triazole)

1H NMR (400 MHz, CDC1_3; 25 °C, TMS): δ 7.78 (d, J = 7.4 Hz, Ph), 7.57- 7.54 (m, Ph), 7.50- 7.45 (m, Ph), 7.39- 7.32 (m, Ph), 7.31- 7.28 (m, Ph), 7.17- 7.15 (m, Ph), 2.78 (q, J = 7.5 Hz, CH₂), 1.32 (t, J = 7.7 Hz, CH₃) ppm. (The signals of phenyl of 12h overlap with 12h ).

12h (4-ethyl- 1 ,5-diphenyl- 1H- 1 ,2,3-triazole)

1H NMR (400 MHz, CDC1_3; 25 °C, TMS): δ 7.78 (d, J = 7.4 Hz, Ph), 7.57- 7.54 (m, Ph), 7.50- 7.45 (m, Ph), 7.39- 7.32 (m, Ph), 7.31- 7.28 (m, Ph), 7.17- 7.15 (m, Ph), 2.90 (q, J= 7.5 Hz, CH₂), 1.08 (t, J₇ = 7.3 Hz, CH₃ ) ppm. (The signals of phenyl of 12h overlap with 12h ).

¹³C NMR (100 MHz, CDC1_3; 25 °C, TMS) (Mixture of 12h and 12h^'): δ 147.3, 144.2, 136.8, 136.5, 135.5, 133.5, 131.5, 129.7, 129.53, 129.5, 129.1, 128.8, 128.74, 128.7, 128.65, 127.8, 127.6, 127.2, 125.8, 124.8, 18.6, 16.7, 14.1, 13.2 ppm. (The signals of 12h are too weak to distinguish from 12h'). HRMS: calcd for Ci₆Hi₆N₃ [M + H]⁺ 250.138, found 250.139.

Eluent: Hexane: Ethyl acetate

Claims

We Claim:

1. A compound of formula (I)

Formula (I)

wherein,

Rl is individually selected from a group comprising straight or branched chain alkyl, straight or branched chain alkenyl, straight or branched chainalkynyl, aryl, alkaryl, aralkyl, heteroaryl and heteroaralkyl, wherein each of them is optionally substituted,

M is a metal selected from a group comprising copper, silver, gold, palladium, titanium, chromium, manganese, iron, cobalt, nickel, zinc, zirconium, molybdenum, rhodium, cadmium, osmium, platinum, tin and germanium; and

X is a halide selected from a group comprising chloro, bromo, iodo and fluoro.

2. A process for preparing compound of formula (I) as claimed in claim 1, said process comprising step of reactin a compound of formula (II)

Formula (II) wherein,

Rl is individually selected from a group comprising straight or branched chain alkyl, straight or branched chain alkenyl, straight or branched chainalkynyl, aryl, alkaryl, aralkyl, heteroaryl and heteroaralkyl, wherein each of them is optionally substituted, and

X is a halide selected from a group comprising chloro, bromo, iodo and fluoro. with a compound of formula (III)

MX

Formula (III)

wherein,

M is a metal selected from a group comprising copper, silver, gold, palladium, titanium, chromium, manganese, iron, cobalt, nickel, zinc, zirconium, molybdenum, rhodium, cadmium, osmium, platinum, tin and germanium; and

X is a halide selected from a group comprising chloro, bromo, fluoro, and iodo, in presence of silyl derivative and solvent.

The process as claimed in claim 2, wherein the silyl derivative is selected from a group comprising potassium bis(trimethylsilyl)amide, lithium

bis(trimethylsilyl)amide and combinations thereof.

The process as claimed in claim 2, wherein the solvent is selected from a group comprising tetrahydrofuran, ether and combinations thereof.

The process as claimed in claim 2, wherein said process is carried out at a temperature ranging from about -100 °C to about 50 °C, preferably at a temperature ranging from about -80 °C to about 25 °C and for a time period ranging from about 20 min to about 14 hours, preferably for a time period ranging from about 30 min to about 13 hours.

A catalyst system comprising at least one compound of formula (I) claimed in claim 1.

7. A process of activating alkyne functionality or azide functionality, said process comprising step of reacting the alkyne functionality or azide functionality with compound of formula (I) as claimed in claim 1.

8. A process for preparing triazole compounds, said process comprising step of reacting a first reactant having an azide functionality and a second reactant having an alkyne functionality, in presence of compound of formula (I) as claimed in claim 1.

9. The process as claimed in claims 7 or 8, wherein the azide functionality is selected from a group comprising aliphatic azide, aryl azide, sterically hindered azides and combinations thereof, wherein each of them is optionally substituted.

10. The process as claimed in claims 7 or 8, wherein the alkyne functionality is selected from a group comprising electron rich alkynes, electron poor alkynes, sterically hindered alkynes, internal alkynes and combinations thereof, wherein each of them is optionally substituted.

11. The process as claimed in claims 7 or 8, wherein said process is carried out at a temperature ranging from about 25 °C to about 70 °C, preferably at a temperature of about 25 °C and for a time period ranging from about 3 minutes to about 10 hours, preferably for a time period ranging from about 5 minutes to about 9 hours.