CA3024425A1 - Novel ionic half sandwich ruthenium complexes supported by n-heterocyclic carbene and/or phosphines, as efficient transfer hydrogenation catalysts - Google Patents

Novel ionic half sandwich ruthenium complexes supported by n-heterocyclic carbene and/or phosphines, as efficient transfer hydrogenation catalysts Download PDF

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CA3024425A1
CA3024425A1 CA3024425A CA3024425A CA3024425A1 CA 3024425 A1 CA3024425 A1 CA 3024425A1 CA 3024425 A CA3024425 A CA 3024425A CA 3024425 A CA3024425 A CA 3024425A CA 3024425 A1 CA3024425 A1 CA 3024425A1
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Van Hung Mai
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Abstract

Acridine....................................................................... ............................................24 4-[CH3C(=O)]C6H4CN............................................................... ............................ 25 4-[HC(=O)] C6H4CN......................................................................... ......................26 4-Et(C=O)NHC6H4CN................................................................ ............................27 4-MeO-C6H4CN......................................................................... .............................28 4-NH2C6H4CN...................................................................... ..................................29 Ethyl methacrylate................................................................... ................................30 Sulfonylbenzonitrile........................................................... .......................................31 VIII-3. X-ray crystal structure of [Cp(IPr)Ru(pyr)2][PF6]..........................................32 Figure 9. The molecular structure of complex [Cp(IPr)Ru(pyr)2][PF6]. The counter-anion, the THF solvate, and hydrogen atoms are omitted for clarity........................32 IX. Reference...................................................................... .....................................32 I. Title Novel ionic half sandwich ruthenium complexes supported by N-heterocyclic carbene and/or phosphines, as efficient transfer hydrogenation catalysts. II. Abstract The ionic half-sandwich complexes of ruthenium (II) with the formula of (I), where Cp* are selected from cyclopentadienyl or pentamethylcyclopentadienyl groups. Ligands L1, L2 and L3 of the complex (1) can be the same or different from each other, the moieties groups of ligands L1, L2 and L3 are N-containing molecules, and/or O-containing molecules, and/or S-containing molecules, and/or P-containing molecules, for examples, N-heterocylic carbene, phosphines, pyridines, nitriles, thiourea, and others. Anion of the compound (I) can be varied from low coordinating to non-coordinating anions, for example, triflate (CF3SO3-) tetrafluoroborate ([BF4]-), hexafluorophosphate ([PF6]-), perchlorate ([ClO4]-), tetrakis-[3,5 -bis(trifluoromethyl)phenyl]borate ion, [B[3,5-(CF3)2C6H3]4]-, tetrakis-(pentafluorophenyl)-borate (B(C6F5)4-) and A1(OC(CF3)3)4-. Furthermore, the preparation and catalytic reactivity of these complexes are described. L1, L2, L3 = N-containing molecules and/or O-containing molecules and/or S-containing molecules and/or P-contaning molecules, for examples, N-heterocylic carbene, phosphines, pyridines, nitriles, thiourea,and others Anion.THETA. = Either low-coordinating or noncoordinating anions such as triflate (CF3SO3-) tetrafluoroborate ([BF4]-), hexafluorophosphate ([PF6]), perchlorate ([ClO4]-), tetrakis[3,5 -bis(trifluoromethyl)phenyl]borate ion, [B[3,5-(CF3)2C6H3]4]-, tetrakis(pentafluorophenyl)borate (B(C6F6)4-) and Al(OC(CF3)3)4-Cp*=Cyclopentadinyl or pentamethylcyclopentadienyl Figure 1. Half sandwich ruthenium complexes III. Field of the invention The present patent relates to new ionic half sandwich ruthenium complexes, which are useful as efficient transfer hydrogenation catalysts. IV. A broad description of the invention One of the most important processes to synthesis N-containing compounds is the reduction of nitriles. The conventional method to reduce nitrile is the stoichiometric usage of metal hydrides LiA1H4 or NaBH4, hydrosilanes, or Hantzsch ester.1-3 These methods normally end up with many economic and environmental issues such as poor atom efficiency, low selectivity, expensive and hazardous reagents, less tolerated to functional groups, and wasteful by-products. In this invention, we have now surprisingly discovered the new half sandwich ruthenium complexes,4-11 which shows the significant performance in the transfer-hydrogenation of nitriles under mild conditions. In addition, these new compounds also display excellent bio-reactivities. The scope

Description

Contents I. ................................................................. Title II. ................................................................ Abstract Figure 1. Half sandwich ruthenium complexes ........................ 4 III. ............................................................... Field of the invention 4 IV. ................................................................ A broad description of the invention 4 V. .................................................................
Description of figures and tables 5 VI. ................................................................ Detailed description of the invention 5 VI.1 Experimental 1: The preparation of ruthenium complexes supported by NHC
carbenes ligands. ........................................................... 5 [CpRu(pyr)3]PF6: ................................................... 5 (Cp*RuCI)4: ........................................................ 5 Synthesis of [Cp*RuCldn ............................................ 5 Synthesis of [Cp*RuCl],t ........................................... 6 [Cp(IPORu(pyr)2WF6: ................................................ 6 Cp(IPr)RuCI: ...................................................... 6 [Cp(IPr)Ru(NCCH3)2]BArF= ........................................... 7 [Cp(IMes)Ru(pyr)21[PF6]: ........................................... 7 Cp*(IPr)RuCl = ..................................................... 7 [Cp*(IPORu(NCCH3)2FF6: ............................................. 8 Cp*(IMes)RuCl: ..................................................... 8 [Cp*(IMes)Ru(NCCH3)2WF6: ........................................... 8 VI.2 Experimental 2: The preparation of thioureas based ruthenium complexes [Cp(IPr----S)Ru][PF6] .............................................. 9 (CpRu)2.-12-(IMes=S): .............................................. 9 [CpRu(ItBu=S)(NCCH3)2][PF6]= ....................................... 10 VI.3 Experimental 3: Catalytic reactivity studies of several ruthenium complexes: 10 Catalytic transfer hydrogenation (TH) studies of [Cp(IPr=S)Ru][PF6] (2) 10 Transfer hydrogenation of imines and cyclic imines by catalyst [Cp(IPr=S)Ru][PF6 10 Table 1. The TH of imines and cyclic imines catalyzed by [Cp(IPr=S)Ru][PF6]

Transfer hydrogenation of conjugated ester and olefins by catalyst [Cp(IPr=S)Ru][PF6] 12 Table 2. The TH of conjugated olefins catalyzed by [Cp(IPr=S)Ru][PF6] .. 12 Transfer hydrogenation of nitriles by [Cp(IPr=S)Ru][PF6] ........... 13 Table 3. The TH of nitriles catalysed by [Cp(IPr=S)Ru][PF6] ........ 13 Transfer hydrogenation of ketones and aldehydes by catalyst [Cp(IPr=S)Ru][PF6]

Table 4. The TH of ketones and aldehydes catalyzed by catalyst [Cp(IPr=S)Ru][PF6] 15 VII. Claims ........................................................ 17 Figure 1. Half sandwich ruthenium complexes ........................ 17 Figure 5. The preparation of the ionic half sandwich ruthenium complexes (I) VIII. ..............................................................
Supporting information 19 VIII-1. Several NMR spectra examples of half sandwich ruthenium complexes [Cp(IPr) Ru(NCCH3)2]BArF ........................................... 19 Figure 6. 1H NMR (600 MHz, 22 C, NCCD3) of [Cp(IPr)Ru(NCCH3)2]BArF .. 20 Figure 7. 13C{1H} NMR spectrum (151 MHz, 22 C, NCCD3) of [Cp(IPr)Ru(NCCH3)2]BArF ............................................ 20 Figure 8. 1113{111} NMR spectrum (151 MHz, NCCD3) of [Cp(IPr)Ru(NCCH3)2]BArF
................................................................... 21 VIII-2. Stacked NMR spectra of catalytic samples using [Cp(IN=S)Rul[PF6] 22 3-CH3C(0)C6H4CN .................................................... 22 3-aminoacetophenone ................................................ 23 Acridine ........................................................... 24 4-[CH3C(=0)]C6H4CN ................................................. 25 4 - [HC(=0)] C6RIEN ................................................ 26 4-Et(C=0)NHC6H4CN .................................................. 27 4-Me0-C6H4CN ....................................................... 28 4-NH2C6H4CN ........................................................ 29 Ethyl methacrylate ................................................. 30 Sulfonylbenzonitrile ............................................... 31 VIII-3. X-ray crystal structure of [Cp(IPORu(pyr)21[PF61. .......... 32 Figure 9. The molecular structure of complex [Cp(1Pr)Ru(pyr)2][PF61. The counter-anion, the THF solvate, and hydrogen atoms are omitted for clarity .. 32 IX. Reference ...................................................... 32 I. Title Novel ionic half sandwich ruthenium complexes supported by N-heterocyclic carbene and/or phosphines, as efficient transfer hydrogenation catalysts.
II. Abstract The ionic half-sandwich complexes of ruthenium (II) with the formula of (I), where Cp* are selected from cyclopentadienyl or pentamethylcyclopentadienyl groups. Ligands L1, L2 and L3 of the complex (1) can be the same or different from each other, the moieties groups of ligands Ll, L2 and L3 are N-containing molecules, and/or 0-containing molecules, and/or S-containing molecules, and/or P-containing molecules, for examples, N-heterocylic carbene, phosphines, pyridines, nitriles, thiourea, and others. Anion of the compound (I) can be varied from low coordinating to non-coordinating anions, for example, triflate (CF3S03-) tetrafluoroborate ([BF4]-), hexafluorophosphate ([PF6r), perchlorate ([C104]), tetrakis-[3,5 bis(trifluoromethyl)phenyl]borate ion, [B[3,5-(CF3)2C6H3[4]-, tetrakis-(pentafluoropheny1)-borate (B(C6F5)4) and Al(OC(CF3)3)4-. Furthermore, the preparation and catalytic reactivity of these complexes are described.
pp.
/ (i) Ruõ

Anion Li, L2, L3 = N-containing molecules and/or 0-containing molecules and/or S-containing molecules and/or P-contaning molecules, for examples, N-heterocylic carbene, phosphines, pyridines, nitriles, thiourea,and others Anion8 = Either low-coordinating or noncoordinating anions such as triflate (CF3S03") tetrafluoroborate ([B F4]), hexafluorophosphate ([PF6]), perchlorate ([C104]), tetrakis[3,5 -bis(trifluoromethyl)phenyl]borate ion, [B[3,5-(CF3)2C6H3]4r, tetrakis(pentafluorophenyl)borate (B(C6F5)4-) and Al(OC(CF3)3)4-Cp"=Cyclopentadinyl or pentamethylcyclopentadienyl Figure 1. Half sandwich ruthenium complexes III. Field of the invention The present patent relates to new ionic half sandwich ruthenium complexes, which are useful as efficient transfer hydrogenation catalysts.
IV. A broad description of the invention One of the most important processes to synthesis N-containing compounds is the reduction of nitrites. The conventional method to reduce nitrite is the stoichiometric usage of metal hydrides LiA1H4 or NaBH4, hydrosilanes, or Hantzsch ester.1-3 These methods normally end up with many economic and environmental issues such as poor atom efficiency, low selectivity, expensive and hazardous reagents, less tolerated to functional groups, and wasteful by-products. In this invention, we have now surprisingly discovered the new half sandwich ruthenium complexes,4-11 which shows the significant performance in the transfer-hydrogenation of nitrites under mild conditions. In addition, these new compounds also display excellent bio-reactivities. The scope of this invention is to reveal the preparation, catalytic reactivity and bioreactivity of novel half-sandwich ruthenium complexes (II) supported by different ligands.
V. Description of figures and tables Figure 1 is the general formula of the novel half sandwich ruthenium complexes (I). Figure 2, 3 and 4 are the bioreactivity test results of several half sandwich ruthenium compounds. Figure 5 is the preparation process of the novel ruthenium compounds with different anions and ligands.
Figure 6, 7 and 8 are the NMR spectra of one example compound with the chemical structure of [Cp(IPORu(NCCH3)2113ArF. Figure 9 is the molecular structure of complex [Cp(IPORu(pyr)2][PF6], where the counter-anion, the THF solvate, and hydrogen atoms are omitted for clarity. Table 1, 2, 3 and 4 are the catalytic results of complex [Cp(IPr=S)Rul[PF6].
VI. Detailed description of the invention VI.1 Experimental 1: The preparation of ruthenium complexes supported by NHC
carbenes ligands.
[CpRit(pyr)3]PF6:
[CpRu(NCCH3)3][PF6] (0.250 g, 0.576 mmol) was placed in a Schlenk tube equipped with a magnetic stirring bar. Dry pyridine (20 mL) pre-saturated with N2 was added. The yellow solution was stirred at room temperature for 24 h. Volatiles were removed under vacuum to give 0.310 g of [CpRu(pyr)3]PF6 as a dark yellow, air sensitive solid. Yield 98%. 1H NMR (600 MHz, CD2C12): 8 4.19 (s, 5 H, Cp), 7.38 (t, J(H¨H) = 7.0 Hz, 6H, py), 7.82 (t, J(H¨H) = 7.8 Hz, 3H, py), 8.52 (t, J(H¨H) = 7.0 Hz, 6H, py).
13C{IH} NMR
(600 MHz, CD2C12): 6 53.4 (s, Cp), 125.7 (s, NCCC), 137.3 (s, NCCC), 154.5 (s, NCCC). Anal.
(Cp*RuC1)4:
Synthesis of [Cp*RuC12.1 n The synthesis of [Cp*RuCl2],, was performed based on a previously reported procedure under N2 atmosphere. Pentamethylcyclopentadiene (20 mL, 143.7 mmol) was added to a solution of RuC13.nH20 (13 g, 57.5 mmol) in CH3OH (600 mL). The resulting solution was refluxed for 7 h until the color reaction mixture changed from green to brown-red. The brown-red solution was kept for 12 h at -80 C. The solution was then filtered, and the residue was washed with hexane to remove Cp*2Ru. The residue was dried under vacuum to afford [Cp*RuC12] as a brown solid.
Yield 11.3 g (62 %).
Synthesis of [Cp*RuCl] 4 To a 100 mL schlenk tube equipped with a magnetic stirring bar was added:
11.3g [Cp*RuCldn, 2.6g (0.04 mol) of Zn, and 500mL of methanol. The mixture was stirred at 50 C
for 24h. All volaties was then removed under vacuo. The crude solid was extracted by benzene, and the resulting brown solution was dried under high vacuum to yield 9.5 g (87%) of [Cp*RuC1]4.
[Cp(IPt)Ru(pyr)21PF6:
To [CpRu(pyr)3][PF6] (0.250 g, 0.456 mmol) in 20 mL dichloromethane solution was added IPr NHC (0.174 g, 0.456 mmol). After stirring at room temperature for 1 day, the resulting solution was dried to yield 4 as a brownish-yellow, air sensitive solid (0.380 g, 97%). This new compound was recrystallised from a THF/hexane (4 : 1 v/v) mixture to give a THF solvate of [Cp(IPORu(pyr)21PF6. 1H NMR (300 MHz, CD2C12): 8 1.13 (d, J(H-H) = 6.9 Hz, 12H, CH3), 1.30 (d,./(H-H) = 7.0 Hz, 12H, CH3), 2.82 (sept, J(H-H) = 7.0 Hz, 4H, CH in 'Pr), 3.77 (s, 5H, Cp), 7.11 (s, 2H, NCH), 7.32-7.46 (m, 6H, C6H3), 7.5 (t, J(H-H) = 6.8 Hz, 4H, m-pyr), 7.9 (t, J(H-H) = 6.8 Hz, 2H, p-pyr), 8.5 (d, J(H-H) = 6.8 Hz, 4H, o-pyr). 31P NMR: -145.6 (sept, J(P-F) = 709 Hz, PF6). Anal. Cal. for C501-167RuN402PF6 (1002.13) C, 59.93; H, 6.74; N: 5.59.
Found: C, 60.74, H, 6.76; N: 5.24.
Cp(IPr)RuCl:
Addition of 0.012 g (0.29 mmol) of LiC1 to a THF solution of 0.250 g (0.29 mmol) of [Cp(IPr)Ru(pyr)2][PF6] gave a deep blue solution of Cp(IPr)RuCl. All volatiles were removed under vacuum, and the residue was extracted by toluene, filtered, and dried to give 0.138 g (0.23 mmol) of Cp(IPr)RuCl. This product was further recrystallized from a mixture of toluene and hexane (2:3) at -30 C. Isolated yield: 80%. The compound is highly moisture sensitive. 1H
NMR (C6D6): 8 1.16 (d,3J(H-H) = 6.8 Hz, 12H, CH3 of 'Pr), 1.49 (d,3J(H-H) =
6.8 Hz,12H, CH3 of 'Pr), 3.43 (sept, 3J(H¨H) = 6.8 Hz, 4H, CH of 'Pr), 3.68 (s, 5H, Cp), 6.68 (s, 2H, NCH), 7.19-7.27 (m, 6H, C6H3). "C NMR (C6D6): 8 26.4 (s, CH3 of 'Pr), 22.9 (s, CH3 of 'Pr), 28.7 (s, CH of Tr), 61.9 (Cp), 124.4 (NCH), 123.7 (s, m-C6H3), 129.8 (s, p-C6H3), 198.7 (Ru-CN2).
Anal. Calcd for C32H41RuN2C1Ø5toluene (636.274): C, 67.01; H, 7.13; N, 4.40.
Found: C, 67.34; H, 6.94; N, 4.81.
[Cp(IPr)Ru(NCCH3)2] BArF:
Reaction of 0.200 g (0.34 mmol) of Cp(1Pr)RuCI with 0.296 g (0.34 mmol) of LiBArF in acetonitrile at room temperature yields a solution of [Cp(IPORu(NCCH3)2p3ArF
and a precipitate. The precipitate was filtered off, and the filtrate was dried under vacuum to yield 0.420 g of [Cp(IPORu(NCCH3)2113ArF. Yield: 93% (0.420 g). 1H NMR (CD3CN): 8 1.14 (d, 3./(H-11) = 7.0 Hz, 12H, CH3 of 'Pr), 1.28 (d, 3./(1-1¨H) = 7.0 Hz, 12H, CH3 of 'Pr), 1,96 (s, 6H, CH3CN), 2.81 (sep, J(H¨H) = 7.0 Hz, 4H, CH of 'Pr), 3.77 (s, 5H, Cp), 7.29 (s, 2H, NCH), 7.36-7.5 (m, 6H, C6H3). 13C NMR (CD3CN): 6 0.8 (NCCH3), 25.0 (CH3 of 'Pr), 21.9 (CH3 of 'Pr), 28.5 (CH of 'Pr), 73.2 (Cp), 125.9 (NCH), 123.8 (mC-C6H3), 130.4 (pC-C6H3), 137.0 (NCCH3), 185.4 (Ru-CN2). 11B NMR (CD3CN): 8 ¨16.69. 19F NMR (CD3CN): S ¨169.3, ¨163.8 (t,3J(F¨F) = 20.4 Hz), ¨133.7 (t,3J(F¨F) = 20.4 Hz). Anal. Calcd for C6o1-147RuBF2oN4 (1315.891): C, 54.76; H, 3.60; N, 4.26. Found: C, 54.54; H, 3.84; N, 4.55.
[Cp(IMes)Ru(pyr)21 [PF61 :
To [CpRu(pyr)3][PF6] (0.200 g, 0.36 mmol) in 20 mL dichloromethane solution was added IMes (0.137 g, 0.456 mmol). After stirring at room temperature for 1 day, the resulting solution was dried to yield [Cp(IMes)Ru(pyr)2][PF6] as a brownish-yellow, air sensitive solid.
This new compound was recrystallised from a 5mL THF/hexane (4 : 1 v/v) mixture to give a THF solvate of 0.18 g (64%) [Cp(IMes)Ru(pyr)2113F6. 1H NMR (400 MHz, CD2C12):
8 1.13 (s, 12H, CH3), 1.30 (s, 12H, CH3), 23.77 (s, 5H, Cp), 7.11 (s, 2H, NCH), 7.38 (s, 4H, C6H3), 7.52 (t, J(H¨H) = 6.8 Hz, 4H, m-pyr), 7.88 (t, J(H¨H) = 6.8 Hz, 2H, p-pyr), 8.49 (d, J(H¨H) = 6.8 Hz, 4H, o-pyr). 31P NMR: ¨144.3 (sept, J(P¨F) = 710 Hz, PF6).
Cp* (IPORitC1 :
To the brown solution of 0.5 g (1.8 mmol) [Cp*RuCl]a in 100 mL THF was added 0.687g (1.8 mmol) IPr. After stirring at room temperature for 24h, the resulting purple solution was dried to yield corresponding unsaturated 16e Cp*(NHC)RuCI as a brownish-yellow, air sensitive solid. Then the crude product was recrystalize in the 50 mL mixture of benzene and hexane ( 4:1 v/v) at -30 C to yield analytically pure Cp*(IPr)RuC1.1H and 13C{1H} NMR
spectra of the compounds matched with Nolan's procedure.
[Cp*(IPr)Ru(NCCH3)2JPFo:
Reaction of 0.2 g (0.3 mmol) of Cp*(IPr)RuCl with 0.26 g (0.3 mmol) of AgPF6 in acetonitrile at room temperature yields a solution of [Cp(IPORu(NCCH3)2FF6 and a precipitate.
The precipitate was filtered off, and the filtrate was dried under vacuum to afford the crude [Cp*(IPr)Ru(NCCH3)2]PF6. The crude product was recrystalize in the 12 mL
mixture of ether and hexane (5:1) to yield 0.2 g (78%) [Cp*(IPr)Ru(NCCH3)2]PF6. 1H NMR (CD3CN):
5 1.12 (d, 3J(H-H) = 6.7 Hz, 12H, CH3 of 'Pr), 1.14 (s, 15H, CH3 of Cp*) 1.34 (d,3J(H-H) = 6.7 Hz, 12H, CH3 of 'Pr), 1,93 (s, 6H, CH3CN), 2.93 (sep, J(H-H) = 6.7 Hz, 4H, CH of 1Pr), 7.11 (s, 2H, NCH), 7.37-7.47 (m, 6H, CH3). 13C NMR (101 MHz, CD3CN): 5 1.3 (NCCH3), 9.75 (CH3 of Cp*), 23.0 (CH3 of 'Pr), 25.9 (CH3 of 'Pr), 29.2 (CH of 'Pr), 83.8 (Cp*), 125.0 (NCH), 127.7 (pC-C6H3), 131.1 (oC-C6H3), 140.2 (mC-CH3), 140.2 (CH3-CC2 of C6H3), 188.0 (Ru-CN2). 31P
NMR (162.0 MHz, CD3CN): -144.7 (sept, J(P-F) = 712 Hz, PF6). Anal. Calcd for C44158F6N4PRu (852.96): C, 57.73; H, 6.85; N, 6.57. Found: C, 56.38; H, 6.96;
N, 6.39.
Cp*(IMes)RuCl:
To the brown solution of 0.5 g (1.8 mmol) [Cp*RuCl]t in 100 mL THF was added 0.54 g (1.8 mmol) IMes. After stirring at room temperature for 24h, the resulting purple solution was dried to yield corresponding unsaturated 16e Cp*(NHC)RuCl as a brownish-yellow, air sensitive solid. Then the crude product was recrystalize in the 50 mL mixture of benzene and hexane ( 4:1 v/v) at -30 C to yield analytically pure 0.67 g (65%) Cp*(IPr)RuCl. 1H and 13C{11-1} NMR
spectra of the compounds matched with Nolan's procedure.
[Cp*(IMes)Ru(NCCH3)2]PF6:
Reaction of 0.5 g ( 0.87 mmol) of Cp*(IMes)RuCI with 0.75 g (0.87 mmol) of AgPF6 in acetonitrile at room temperature yields a solution of [Cp(IMes)Ru(NCCH3)2113F6 and a precipitate AgCl. The precipitate was filtered off, and the filtrate was dried under vacuum to afford the crude [Cp*(IMes)Ru(NCCH3)2]PF6. The crude product was recrystalize in the 12 mL
mixture of ether and hexane (5:1) to yield 0.6 g (90%) [Cp*(IMes)Ru(NCCH3)21PF6. 1H NMR
(CD3CN): 8 1.10 (d, 3J(H-H) = 6.7 Hz, 12H, CH3 of 'Pr), 1.12 (s, 15H, CH3 of Cp*) 1.34 (d, 3J(H-H) = 6.7 Hz, 12H, CH3 of 'Pr), 1,93 (s, 6H, CH3CN), 2.93 (sep, J(H-H) =
6.7 Hz, 4H, CH
of 'Pr), 7.11 (s, 2H, NCH), 7.37-7.47 (m, 6H, C6H3). 13C NMR (101 MHz, CD3CN):
8 1.3 (NCCH3), 9.75 (CH3 of Cp*), 23.0 (CH3 of 'Pr), 25.9 (CH3 of 'Pr), 29.2 (CH of 'Pr), 83.8 (Cp*), 125.0 (NCH), 127.7 (pC-C6H3), 131.1 (oC-C6H3), 140.2 (mC-C6H3), 140.2 (CH3-CC2 of C61-13), 188.0 (Ru-CN2). 311) NMR (162.0 MHz, CD3CN): -144.7 (sept,J(P-F) = 712 Hz, PF6).
VI.2 Experimental 2: The preparation of thioureas based ruthenium complexes [Cp(IPr.S)Ru] [PF6]
To the solution of 2*0.5 g (2*1.15 mmol) of [CpRu(NCCH3)3]13F6 in 10 mL of dichloromethane was added 0.45 g (1.15 mmol) IPr=S ligand. The mixture was stirred at RT for 30 m. All volatiles were removed under high vacuum to yield the yellow crude of [Cp(IPr=S)Ru][PF61. Then the product was then recrystallized from a mixture of dichloromethane and hexane (4:1 v/v) to yield the analytically pure [Cp(IPr=S)Ru][PF61 which is characterized by NMR, IR, and EA.
1H NMR (600 MHz, CD2C12): 6 1.17 (s, 6H, CH3 of 'Pr), 1.27 (s, 18H, CH3 of 'Pr), 2.52 (s, 2H, CH of 'Pr), 2.70 (s, 2H, CH of 'Pr), 5.53 (s, 5H, Cp), 7.32 (d, 2H, NCH), 6.27 (d, 3H, 113 of C6H3), 7.32 (d, 2H, C6H3), 7.51 (s, 1H, C6H3). 13C NMR (151 MHz, CD2C12): 23.3 (CH3 of 'Pr), 23.6 (CH3 of 'Pr), 24.4 (CH3 of 'Pr), 24.5 (CH3 of 'Pr), 28.5 (CH3 of 'Pr), 29.5 (CH of 'Pr), 82.1 (Cp), 84.3 (Cp), 109.7 (pC-13-C6H3), 112.4 (mC-113-C6H3), 120.2 (oC-13-C6H3), 124.9 (NCH), 130.9 (mC-C6H3), 133.9 (pC-C6H3), 146.8 (oC-C6H3), 167.0 (Ru-SCN2). Anal. Calcd for Chemical Formula:
C33F145F6N2PRuS Calculated Elemental Analysis: C, 53.00; H, 6.07; N, 3.75; S, 4.29. Found: C, 52.79; H, 6.72; N, 4.01; S, 4.17.
(CpRu)2-g2-(IMes=S):
The addition of 1.5 g (3.46 mmol) of [CpRu(NCCH3)3]PF6 to the 50 mL solution of 0.58 g (1.15 mmol) IMes=S ligand in dichloromethane yielded a slurry mixture, which was stirred for 24h at room temperature. After, all volatiles were removed under high vacuum to yield the yellowish brown crude product, which was then re-crystallized in a mixture of dichloromethane and hexane (4:1 v/v) to yield the crystalline product (CpRu)2- 2-(IMes=S).
This product was characterized by NMR, IR, X-ray crystallography, and EA. Chemical Formula:
C351146N2Ru2S.
Calculated Elemental Analysis: C, 57.67; H, 6.36; N, 3.84; S, 4.40. Found: C, 58.12; H, 6.89; N, 3.55; S, 4.17.
[CpRit(ItBit.S)(NCCH3)2HPF61:
To the solution of 0.75 g (1.73mm01) of [CpRu(NCCH3)3]PF6 in 10 mL of dichloromethane was added 0.24 g (1.15 mmol) ItBu=S ligand. The mixture was stirred at room temperature for 24h. All volatiles were removed under high vacuum to yield the yellow crude of a mixture of several products. Attempts to isolate the product were failed, and the 1H-NMR
characterization in CD2C12 of the crude showed the mixture of several products which may be sulfur-bridged dimeric complexes. Further investigations need to be done to clarify the structures of the resulting complexes.
VI.3 Experimental 3: Catalytic reactivity studies of several ruthenium complexes:
Catalytic transfer hydrogenation (TH) studies of [Cp(1Pr.S)RullPF01 (2) Transfer hydrogenation of imines and cyclic imines by catalyst [Cp(IPr=S)Rul [PF6 After the TH of CEN and C=0 bonds, the scope of the reaction was next extended to the reduction of C=N bonds and C=C bonds under the optimized conditions (Table Si and S2). As observed from our previous studies, the transfer hydrogenation of imines was more sluggish than the reduction of nitrile under the same conditions. As showed Table Si, the reaction of cyclic imines (entries 1-8) only produced the corresponding products in the moderate yields (up to the highest yield of 71% for quinoline). The results of attempted reduction of aliphatic imines were also not as promising as nitriles under this reaction conditions, as the yields of these transformations were very low (entries 10 ¨ 12, 15 ¨ 29 %), with the exception the activated substrates (entries 9, 13 and 14), where the yields were slightly better (68 ¨
81%).

Table 1. The TH of imines and cyclic imines catalyzed by [Cp(IPr.S)Ru][PF61 0.1 mol % 2, 0.3 mol % KOtBu ________________________ HN
1) Ri isopropanol, 80 C Ri
2) organic work up Entry Substrates Yield' (%) I 71.3 (31) Nz iiIi 2 53.0
3 43.6 I
CC)
4 31.2 NR
6 54.9 N
9 79.3 C=N 25.2 d 11 1OMe 29.1 c;
N
C-11, 12 ¨0 15.1 13 * 6 / 81.1 (68.2) =
14 7.9 S-N
a Yields are calculated based on NMR scale reactions: 0.1 mol % catalyst, 0.3 of mol % base, 50 pmol of the substrate, at 80 C in 0.8 mL of IPA for 30 min.
Transfer hydrogenation of conjugated ester and olefins by catalyst [Cp(1Pr=S)Rig[PF61 In the course of our previous studies on the TB of conjugated olefins, we noticed that the reaction went through the formation of both kinetically favorable species (Michael addition reaction) and thermodynamically favorable products (Hydrogenation reaction) (Table S2).4 As a result of having activated binding sites, conjugated substrates (entries 1 ¨
9) were reduced with higher yields (65 ¨92%) comparing to the yields (8-32%) of non-activated olefins (entries 10-14).
Table 2. The TH of conjugated olefins catalyzed by [Cp(IPr=S)Ru][PF61 0.05 mol % 2, OiPr 0.15 mol % KOtBu _____________________________ R3--ç 4O
142 µX--Fti 1) isopropanol, 80 C g2 µX-F22 sX--Ri 2) organic work up Michael Hydrogenation Entry Substrates Yielda(%) H and M
1 0 87 H; 23 M (56) JiNo'Et 2 0 92 H; 8 M (41) 3 0 88 H; 12 M (69) JtEt 4 o 72 H, 28 M
\_ \O-Ph 89 H, 11 M (55) \O-Et 6 0 65 H, 35 M
7 o 76 H, 24 M
,ANMe2 8 NH 2 81 H, 19 M
9 91 H, 9 M (78) C NR
a Yields are calculated based on NMR scale reactions: 0.05 mol % catalyst, 0.15 of mol % base, 50 mot of the substrate, at 80 C in 0.8 mL of IPA for 4h.
Transfer hydrogenation of nitriles by [Cp(IPr=S)RtillPF61 Table 3. The TH of aitriles catalysed by [Cp(IPr.S)Ru][P176]
R¨\\
0.05 mol % 2, 0.15 mol % KOtBu NH2 R¨CN ___________________________________ Or 1) isopropanol, 80 C
2) organic work up R¨\\

Entry Substrates Yields (%) 1 4-Me0C6RICN 97 (63) 2 4-NH2C6H4CN 95 (72) 3 4-EtCO2C6H4CN 83 (69) 4 4-EtC(=0)NHC6H4CN 98 (41) 4-[CH3C(=0)]C6H4CN 99 (83) 6 4-[HC(=0)]C6H4CN 99 7 2,6-(CH3)2C6H3CN 54 9 sulfonylbenzonitrillc 99 11 PhCN 99(89) 12 CH3(CH2)4CN 47 (31) 13 (CH3)3CCN 25 14 HCa-C-(CH2)4CN 44 n-C3H7CN 68 (28) a Yields are calculated based on NMR scale reactions: 0.05 mol % catalyst, 50 limo' of the substrate, 80 C in 0.8 mL of IPA for 30 mm; Large scales for isolated yields were described in general procedure.
Benzonitriles bearing different moieties, such as methoxy, amino, ester, carbonyl, hydroxyl and nitro were also reduced to form the corresponding imine derivatives in good to excellent yields (entries 1-11, Table. 2). Benzonitriles bearing acetyl or aldehyde groups were hydrogenated nonselectively, as the transfer hydrogenation of C=0 bonds occurred before the reduction of CEN
bond (entries 4-6). Similarly to our previous study, the ester moiety of benzonitrile remained untouched under this catalytic condition (entry 3). The reaction of benzonitrile having the sulfonyl proceeded to the complete reduction of substrate to produce the corresponding amine. Para-cyano pyridine was also reduced in a good yield (89); however, the pyridine ring appeared to be intact (entry 10). The reduction of aliphatic nitrites was not as successful as benzonitriles (entries 12-15), which showed the lower moderate yields at the similar reaction time.
Noticeably, the CC
bond appeared to be intact under this reaction conditions (entry 14).
Transfer hydrogenation of ketones and aldehydes by catalyst [Cp(1Pr=S)RullPF6]

0.05 mol % 2, R1 0.15 mol KOtBu R1 1) isopropanol, 80 C HO
The reactivity of cat 2 toward the TH of ketones and aldehydes was also screened under the similar conditions with 0.05 mol % catalyst, 0.15 mol % base at 80 C
(Table 3); the results were very promising; but still less efficient than current well-known ruthenium species developed from Noyori type catalysts. In entry 1, benzaldehyde was hydrogenated effectively with the catalyst loading of 0.05 mol % (in 15 min, at 80 C) to yield 97% of 1-phenylethanol.
Benzaldehydes bearing bromo and methoxy groups (entries 2 and 3) also were reduced successfully with high yields (89 and 96 % respectively). Some alkyl aldehydes such as pentanal and isobutyraldehyde (entries 4 and 5) were hydrogenated with moderate yields.
Acetophenone substrates having different moieties such as methoxy, chloro, amino, formyl or nitro groups were reduced regardless the ortho or para positions of these groups in the proximity of the carbonyl group (entries 6-10). Benzophenone and cyclohexanone (entries 11 and 12) were less likely to be reduced under the same conditions with the very moderate yields of 50 and 33 %
respectively.
Table 4. The TH of ketones and aldehydes catalyzed by catalyst [Cp(IPmS)Ru1[PF6]
Entry Substrates Yields (%) Br Me0 Me0 7 o 83 cH, o2N
cH,

Claims (5)

VII. Claims
1. The ionic half sandwich ruthenium complexes with different anions of formula (I) (Figure 1), where Cp* are selected from cyclopentadienyl or pentamethylcyclopentadienyl groups. Ligands L1, L2 and L3 of the complex (I) can be the same or different from each other, the moieties groups of ligands L1, L2 and L3 arc N-containing molecules, and/or O-containing molecules, and/or S-containing molecules, and/or P-containing molecules, for examples, N-heterocylic carbene, phosphines, pyridines, nitriles, thiourea, and others. Anion of the compound (I) can be varied from low coordinating to non-coordinating anions, for example, triflate (CF3SO3-) tetrafluoroborate ([BF4]-), hexafluorophosphate ([PF6]-), perchlorate ([ClO4), tetrakis-[3,5 -bis(trifluoromethyl)phenyl] borate ion, [B[3,5 -(CF3)2C6H3]4]-, tetrakis-(pentafluorophenyl)-borate (B(C6F5)4-) and Al(OC(CF3)3)4-.
L1, L2, L3 = N-containing molecules and/or O-containing molecules and/or S-containing molecules and/or P-contaning molecules, for examples, N-heterocylic carbene, phosphines, pyridines, nitriles, thiourea,and others Anion~ = Either low-coordinating or noncoordinating anions such as triflate (CF3SO3-) tetrafluoroborate ([BF4]"), hexafluorophosphate ([PF6]-), perchlorate ([ClO4]-), tetrakis[3,5 -bis(trifluoromethyl)phenyl]borate ion, [B[3,5-(CF3)2C6H3]4]-, tetrakis(pentafluorophenyl)borate (B(C6F5)4-) and Al(OC(CF3)3)4-Cp*=Cyclopentadinyl or pentamethylcyclopentadienyl Figure 1. Half sandwich ruthenium complexes
2. The ionic half sandwich ruthenium complexes, according to claim 1, characterized by the fact that L1, L2 and L3 are pyridines, nitrile, phosphines, N-heterocyclic carbenes, or thiourea.
3. Cp* ligands in the ionic half sandwich ruthenium complexes, according to claim 1, characterized by the fact, are either cyclopentadienyl or pentamethylcyclopentadienyl groups.
4. Anions in the ionic half sandwich ruthenium complexes, according to claim 1, characterized by the fact, are from low coordinating to non-coordinating anions, for example, triflate (CF3SO3-) tetrafluoroborate ([BF4]-), hexafluorophosphate ([PF6]-), perchlorate ([C104]-), tetrakis-[3,5 -bis(trifluoromethyl)phenyl]borate ion, [B[3,5-(CF3)2C6H3]4]-, tetrakis-(pentafluorophenyl)-borate (B(C6F04-) and A1(OC(CF3)3)4-.
5. The process for the preparation of the ionic half sandwich ruthenium complexes (I), according to the Claims from 1 to 4, comprising the following reaction steps:
Figure 5. The preparation of the ionic half sandwich ruthenium complexes (I) VIII. Supporting information VIII-1. Several NMR spectra examples of half sandwich ruthenium complexes All manipulations were performed using conventional highvacuum or nitrogen-line Schlenk techniques. Solvents were pre-dried by using Grubbs-type purification columns and stored in ampoules equipped with a Teflon valve. Deuterated solvents were dried over sodium, potassium or CaH2 as appropriate, distilled under reduced pressure and stored in ampoules with a Teflon valve. NMR samples were prepared in New Era tubes equipped with J.
Young-type Teflon valves. NMR spectra were obtained with Bruker DPX-400 and Brucker DPX-instruments (1H: 400 and 600 MHz; 13C: 100.6 and 151 MHz; 29Si: 119.2 MHz;
31P: 162.0 and 243 MHz) spectrometers at 298 K. 1H and 13C NMR spectra were referenced internally to residual protiosolvent (1H) or solvent (13C) resonances and are reported relative to tetramethylsilane (.delta.=0 ppm). Chemical shifts are quoted in .delta.[ppm], and coupling constants in Hertz. IR spectra were recorded by using a PerkinElmer 1600 FTIR spectrometer as Nujol mulls between NaC1 windows. All chemicals were purchased from Sigma¨ Aldrich and Alfa Aesar were used without further purification. C6D6 were purchased from Cambridge Isotope Laboratories, and were dried over CaH2 before use.
[CP(IPr) Ru(NCCH3)2]BArF
Figure 6. 1H NMR (600 MHz, 22°C, NCCD3) of [Cp(IPr)Ru(NCCH3)2]BArF
Figure 7. 13C{1H} NMR spectrum (151 MHz, 22°C, NCCD3) of [Cp(IPr)Ru(NCCH3)2]BArF

Figure 8. 11B{1H} NMR spectrum (151 MHz, NCCD3) of [Cp(IPr)Ru(NCCH3)2]BArF

VIII-2. Stacked NMR spectra of catalytic samples using [Cp(IPr=S)Ru][PF6]
3-CH3C{O)C6H4CN
3-aminoacetophenone Acridine 4-[CH3C(=O)]C6H4CN
4-[HC(=O)]C6H4CN
4-St(C=O)NHC6H4CN
4-MeO-C6H4CN
Ethyl methacrylate Sulfonylbenzonitrile
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112661653A (en) * 2020-12-28 2021-04-16 四川大学 Method for preparing amine by catalytic reduction of nitro compound by cyclic (alkyl) (amino) carbene chromium complex
CN112661653B (en) * 2020-12-28 2023-05-26 四川大学 Method for preparing amine by catalytic reduction of nitro compound by using cyclic (alkyl) (amino) carbene chromium complex

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