CN113461741B

CN113461741B - Saldmpn type nickel (II) halide complex as well as preparation method and application thereof

Info

Publication number: CN113461741B
Application number: CN202110615676.1A
Authority: CN
Inventors: 李天宇; 吴琼; 王宝玲; 黄梅芬; 焦亮; 马寻; 徐新迪
Original assignee: Kunming University
Current assignee: Kunming University
Priority date: 2021-06-02
Filing date: 2021-06-02
Publication date: 2022-07-01
Anticipated expiration: 2041-06-02
Also published as: CN113461741A

Abstract

The invention discloses a Saldmpn type nickel (II) halide complex, a preparation method and application thereof, wherein the complex belongs to a monoclinic system, P2₁A/n space group, the asymmetric unit of which is composed of three neutral Ni^II(3, 5-Cl-salempn) is connected by multiple weak interactions involving halogen bonds, each Ni^IIThe (3,5-Cl-salmen) unit contains a Ni (II) center and a 3,5-Cl-salmen Saldmpn type ligand. The complex is used as a pH sensor based on a smartphone imaging system and is used for constructing a molecular logic gate. The complex provides a research model and data for the electronic structure of the transition metal Schiff base complex and the regulation and control function of halogen bonds, and the constructed inhibitory molecular logic gate has the characteristics of small pH value regulation range, high sensitivity, good signal discrimination, easy operation and the like compared with the known logic gate.

Description

Saldmpn type nickel (II) halide complex and preparation method and application thereof

Technical Field

The invention belongs to the technical field of chemical material synthesis, and particularly relates to a nickel (II) halide complex, and a preparation method and application thereof.

Background

Non-covalent bonds refer to interactions weaker than covalent bonds, and although their strengths are weak, they have been widely used in many fields such as molecular recognition, chiral resolution, crystal engineering, magnetic materials and supramolecular assembly, and the research of non-covalent bond interactions has become a hot spot in academia in recent years. Common non-covalent bonds are hydrogen bonding, ion-dipole and dipole-dipole interactions, hydrophobic interactions, and van der waals attraction, among others. Among them, hydrogen bonding is the most common and strongest intermolecular force in the fields of crystallography and materials science, and has been widely used and calculated with respect to hydrogen bonding. The composition of the hydrogen bond is simple, but the precise regulation and control are difficult, so that the search for a novel non-covalent bond capable of replacing the hydrogen bond is particularly important, and the research becomes a hotspot of the chemical research of the materials.

Halogen bonding is a non-covalent bond interaction similar to a hydrogen bond, where the atom serving as the sigma hole is a halogen atom rather than a hydrogen atom. It has been widely used in many fields such as bioactive systems, catalysis, and drug design. Halogen bonds have also found wide application in the field of crystal engineering over the past few decades and have been used in the synthesis of various new materials. The interaction of halogen bonds is directional compared to hydrogen bonds, and the angle is close to a flat angle, so halogen bonds are more important than hydrogen bonds in crystal engineering. The use of halogen bonds to construct materials with specified structures or properties is thus attractive to many researchers. However, due to the limited computing power and the lack of ideal experimental models, the research on halogen bonds has reached a bottleneck, and only a few researchers are concerned about and insist on the regulation of halogen bonds in metal complexes, and the research is still in the preliminary stage.

The Schiff base material has the unique advantages of ferromagnetism, catalysis, conductivity, low cost and the like, and the design and synthesis of the novel Schiff base complex have great significance for the research and development of the Schiff base complex. The synthesis and use of schiff base compounds has advanced substantially over the last several decades. At present, many studies on Schiff base complexes are carried out, but most of reported halogenated Schiff base complexes rely on organic functional groups to modify ligands, the halogen bond has weak effect and small influence on the structure and the property, the structure of the supermolecule aggregate formed by halogen bond induction is relatively less reported, and the research on the influence of halogen atoms on the fluorescence property of the supermolecule complexes is still in a blank stage.

Therefore, it is necessary to design a supramolecular assembly of a halogenated schiff base complex in which a synthetic halogen bond participates and to give an insight into the influence of its structure on the fluorescence properties.

Disclosure of Invention

In view of the above problems, a first object of the present invention is to provide a Saldmpn-type nickel (II) halide complex, a second object of the present invention is to provide a process for producing the complex, and a third object of the present invention is to provide uses of the complex.

The first object of the present invention is achieved by a Saldmpn-type nickel (II) halide complex of the formula { [ Ni ]^II(3,5-Cl-saldmpn)]₃(1) wherein 3, 5-Cl-salempn = N, N '-bis (3, 5-dichlorosalicylaldehyde) -N, N' -bis (3-aminopropyl) methylamine is monoclinic, P2₁A/n space group, the asymmetric unit of which is composed of three neutral Ni^II(3, 5-Cl-salempn) is connected by multiple weak interactions involving halogen bonds, each Ni^IIThe (3,5-Cl-salmen) unit comprises one Ni (II) center and one 3,5-Cl-salmen Saldmpn type ligand, and the coordination environments of the three Ni centers are different, wherein the geometrical configurations of Ni1 and Ni2 are close to a trigonal bipyramid, the geometrical configuration of Ni3 belongs to a regular tetrahedron, and the calculation shows that tau 1=0.534, tau 2= 0.619, and tau 3= 0.333.

The second object of the present invention is achieved by a process for producing a Saldmpn-type nickel (II) halide complex, comprising the steps of:

1) dissolving 3, 5-dichlorosalicylaldehyde and N, N' -bis (3-aminopropyl) methylamine in methanol and stirring for 2 hours;

2) adding nickel (II) nitrate, stirring for 1.5 hours, and filtering to obtain filtrate;

3) slowly volatilizing the filtrate at room temperature to obtain massive brown crystals, washing the crystals for multiple times by using a polar solvent, filtering, and finally drying to obtain the complex.

The third purpose of the invention is to provide a molecular logic gate constructed by the complex.

The invention has the beneficial effects that:

1. the invention provides a novel Saldmpn type nickel (II) halide complex, which is structurally characterized by FT-IR, UV-Vis, elemental analysis and single crystal X-ray diffraction, and search results of a Cambridge crystal database show that the complex is a supramolecular aggregate based on salempn and constructed by the same unit, so that the complex provides a research model and data for the regulation and control of the electronic structure and halogen bond of a front transition metal Schiff base complex, and has important significance for designing and synthesizing a novel Schiff base metal complex, expanding the application of the Schiff base metal complex and developing Schiff base chemistry.

2. The preparation method of the complex is simple, the reaction can be carried out at room temperature, the test conditions are clear and definite in structure, the separation and purification are convenient, and the yield is up to 36.5%.

3. The supermolecule tripolymer assembly of the complex shows extremely high sensitivity to the change of acid-base environment, when the pH value is increased from 5 to 6, the fluorescence intensity is obviously enhanced by 15 times, and the fluorescence intensity with good stability can be kept for more than 48 hours; in addition, as a potential logic gate unit, the reversible property shows that the complex has the fluorescent property of 'on/off' by controlling the pH value, so that the complex can be used for constructing a molecular logic gate, and compared with the known logic gate, the constructed inhibit type molecular logic gate has the characteristics of small pH value adjusting range, high sensitivity, good signal discrimination, easiness in operation and the like.

4. The luminescence property test of the complex of the invention shows that the fluorescence intensity of the trimer of the complex is very weak, but when the pH is regulated to be pH =6, the fluorescence intensity is obviously increased by 15 times. By comparison with the luminescence properties of the ligands, it is concluded that the fluorescence enhancement is due to decomposition of the trimer into the complex monomer at pH = 6.

Drawings

FIG. 1 is an ultraviolet-visible spectrum of a Saldmpn type nickel (II) halide complex of example 1;

FIG. 2 shows H in example 1₂Ethanol solution of chi-L (50uM)In which Ni is dropped²⁺Ultraviolet-visible spectrum of ions;

FIG. 3 is the association constant of the Saldmpn-type nickel (II) halide complex of example 1;

FIG. 4 shows the χ -L in example 1^2-To Ni²⁺The detection limit of (2);

FIG. 5 is an absorption spectrum of a Saldmpn type nickel (II) halide complex in example 1, wherein a is Ni addition at room temperature²⁺And titrating a halogenated Schiff base ligand (H) under excitation of lambda =360nm₂-fluorescence spectrum of χ -L) (400 μ M) [ Ni²⁺]=0, 40,80,120,160,200,240,280,320,360,400,440,480,520 μ M); b is the maximum fluorescence intensity and (Ni)²⁺/H₂- χ -L) concentration profile;

FIG. 6 is an absorption spectrum of a Saldmpn type non-nickel (II) halide complex in example 1, wherein a is Ni addition at room temperature²⁺And titrating non-halogenated Schiff base ligand (H) under excitation of lambda =360nm₂L) (400. mu.M) fluorescence Spectroscopy, [ Ni ]²⁺]=0, 40,80,120,160,200,240,280,320,360,400,440,480,520 μ M); b is the maximum fluorescence intensity and (Ni)²⁺/H₂L) concentration dependence;

FIG. 7 is a molecular structure diagram of a mononuclear compound of a Saldmpn type nickel (II) halide complex in example 1;

FIG. 8 is a diagram showing the coordination environment of Ni in three Saldmpn type nickel (II) halide complexes of example 1;

FIG. 9 shows fluorescence spectra of [ Ni-chi-L ] in solutions of different pH values in example 1;

FIG. 10 is a graph showing a comparison of fluorescence intensity of a trimer of the Saldmpn-type nickel (II) halide complex and a halogenated Schiff base ligand at pH =10 in example 1;

FIG. 11 shows [ Ni-chi-L ] in example 1]In a pH6 environment, [ H ]₂-χ-L ]、[H₂-L ]、[Ni-χ-L ]And [ Ni-L]And plot of integrated fluorescence intensity in quinine sulfate (reference dye) as a function of absorbance at 360 nm; FIG. 11 (b) is 1.4X 10⁵The following amplification lines;

FIG. 12 shows the different complexes Saldmpn of example 1^2-(Mn²⁺、Fe³⁺、Co²⁺、Ni²⁺、Cu²⁺、Ag⁺、Al³⁺、Bi³⁺、Ca²⁺、Cr²⁺、K⁺、Li⁺、Mg²⁺、Na⁺、Sr²⁺、Zn²⁺) Graph of fold change in fluorescence intensity from pH5 to pH6 in ethanol solution;

fig. 13 is a photograph taken with a smartphone imaging system of example 1 (a); (b) a graph of pH as a function of the brightness values of the red, green and blue channels; (c) a blue channel map;

FIG. 14 shows Saldmpn-type nickel (II) halide complexes (400. mu.M) at pH =5 and 6 (. lamda.M) in example 1_ex=360 nm);

FIG. 15 shows Saldmpn-type nickel (II) halide complexes (400. mu.M) in ethanol solution at pH =5 and 6 (lambda.) (in example 1)_ex=360nm) as a function of time;

FIG. 16 shows the Saldmpn type nickel (II) halide complex as H in example 1⁺And OH^-Is a circuit diagram of a nor gate of an input signal.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to be limiting in any way, and any modifications or alterations based on the teachings of the present invention are intended to fall within the scope of the present invention.

The invention relates to a Saldmpn type nickel (II) halide complex, the molecular formula of which is { [ Ni ]^II(3,5-Cl- saldmpn)]}₃(1) Wherein 3, 5-Cl-salempn = N, N '-bis (3, 5-dichlorosalicylaldehyde) -N, N' -bis (3-aminopropyl) methylamine is monoclinic, P2₁A/n space group, the asymmetric unit of which is composed of three neutral Ni^II(3, 5-Cl-salempn) is connected by multiple weak interactions involving halogen bonds, each Ni^IIOne Ni (II) center and one 3,5-Cl-salmen Saldmpn type ligand are present in the (3,5-Cl-salmen) asymmetric unit.

The asymmetric unit is composed of three crystallographically independent neutral Ni^II(3,5-Cl-salmen), the geometrical configuration of Ni1, Ni2 is close to that of a triangular bipyramid, the geometrical configuration of Ni3 is a regular tetrahedron, wherein τ 1=0.534, τ 2= 0.619, τ 3= 0.333.

The pH values for the formation and separation of the supramolecular trimer of the complex are 5 and 6, respectively.

The preparation method of the Saldmpn type nickel (II) halide complex comprises the following steps:

1) dissolving 3, 5-dichlorosalicylaldehyde and N, N' -bis (3-aminopropyl) methylamine in methanol, and stirring for 1.5-2.5 hours;

2) adding nickel (II) nitrate, stirring for 1-2 hours, and filtering to obtain filtrate;

3) slowly volatilizing the filtrate at room temperature to obtain massive brown crystals, washing the crystals for multiple times by using a polar solvent, filtering, and finally drying to obtain the target complex.

The molar ratio of the 3, 5-dichlorosalicylaldehyde, the N, N' -bis (3-aminopropyl) methylamine and the nickel nitrate (II) is 2: 1-1.1: 1.4-1.5.

In the step 1, the volume ratio of the N, N' -bis (3-aminopropyl) methylamine to the methanol is 1: 4000-5000.

In the step 3, the polar solvent is methanol.

In the step 3, the volatilization time is 7 days.

The complex disclosed by the invention is used as a logic gate unit for establishing a suppression type logic device.

Based on that the fluorescence intensity of the complex is different by more than 15 times under the conditions of pH =5 and 6 under the condition of 400 mu M, the complex can be used for constructing a molecular inhibit logic gate. The construction method of the molecular inhibit logic gate comprises the following specific steps: by weak H⁺And OH^-For input signals, the complex is used as a molecular logic sensing platform, and changes of fluorescence intensity at 521nm are used as output signals to represent '0' and '1' for construction.

The complex disclosed by the invention can be used as a pH sensor based on a smartphone imaging system.

Another use of the complexes of the invention is as pH probes. Based on the fact that the difference of the fluorescence intensity of the complex reaches more than 15 times under the conditions that the pH =5 and 6 under the condition that the concentration of the complex is 400 mu M, the complex can also be used for detecting abnormal cells in vivo, and because the pH value range of normal somatic cells is 6.5-7.5, the separation pH value of the complex can be increased to 6.5 through adjustment of ligands or metal ions, and whether the cells are abnormal cells or not is judged according to the change of the fluorescence intensity.

The present invention is further illustrated by the following examples.

Example 1

0.019g (0.1 mmol) of 3, 5-dichlorosalicylaldehyde and 8.1ul (0.05 mmol) of N, N' -bis (3-aminopropyl) methylamine are stirred in a mixture of 20 mL of methanol at room temperature for 2 hours, after which 0.022g (0.072 mmol) of nickel (II) nitrate is added, the resulting light brown mixture is stirred for a further 1.5 hours and filtered to give a filtrate. The filtrate was slowly evaporated over 7 days to give brown crystals in the form of lumps. Filtering the massive brown crystals, washing the massive brown crystals with methanol for multiple times, and drying the massive brown crystals in the open at room temperature to obtain { [ Ni ]^II(3,5-Cl-saldmpn)]₃} (1), yield 36.5%.

Example 2

0.010g (0.05 mmol) of 3, 5-dichlorosalicylaldehyde and 4 ul (0.025 mmol) of N, N' -bis (3-aminopropyl) methylamine in a mixture of 20 mL of methanol are stirred at room temperature for 1.5 hours, after which 0.011g (0.036 mmol) of nickel (II) nitrate is added, the resulting light brown mixture is stirred for a further 1 hour and filtered to give a filtrate. The filtrate was slowly evaporated over 6 days to give brown crystals in the form of lumps. Filtering the massive brown crystals, washing the massive brown crystals with methanol for multiple times, and drying the massive brown crystals in the open at room temperature to obtain { [ Ni ]^II(3,5-Cl-saldmpn)]₃} (1), yield 34%.

Example 3

0.010g (0.05 mmol) of 3, 5-dichlorosalicylaldehyde and 4 ul (0.025 mmol) of N, N' -bis (3-aminopropyl) methylamine in a mixture of 20 mL of methanol are stirred at room temperature for 2 hours, after which 0.011g (0.036 mmol) of nickel (II) nitrate is added, the resulting light brown mixture is stirred for a further 1.5 hours and filtered to give a filtrate. The filtrate was slowly evaporated over 8 days to give brown crystals in the form of lumps. Filtering the massive brown crystals, washing the massive brown crystals with methanol for multiple times, and drying the massive brown crystals in the open at room temperature to obtain { [ Ni ]^II(3,5-Cl-saldmpn)]₃} (1) The yield was 34%.

Example 4

Different responses of the complex prepared in example 1 to pH were used to construct an INHIBIT molecular logic gate as follows: with H⁺(concentration 1X 10)^-3mol/L) and OH^-(concentration 1X 10)^-3mol/L) as an input item and the fluorescence intensity change of the complex as an output item to construct an INHIBIT molecular logic gate.

The method specifically comprises the following steps: h is to be⁺Ethanol solution (concentration 4X 10) added to the complex^-4mol/L), the system exhibits low fluorescence intensity (I)_ob=1×10⁴) And the output result is '0'; will H⁺Ethanol solution (concentration 4X 10) added to the complex^-4mol/L), the system emits relatively high fluorescence (I)_ob=1×10⁵) The output result is "1".

The properties of the complexes obtained in examples 1-3 were similar, and the following { [ Ni ] was obtained only in example 1^II(3,5-Cl-saldmpn)]₃For example, the structure and properties of (1) were analyzed.

First, structural characterization

C₆₃H₆₃Ni₃Cl₁₂N₉O₆Elemental analysis (Mr = 1643.66): theoretical value: c, 46.03; h, 3.86; n, 7.67; test values: 46.3 percent of C, 4.1 percent of H and 7.6 percent of N.

Uv-vis spectroscopy (fig. 1) data (ethanol as solvent): measurement of H in ethanol solution (50uM) at room temperature₂The UV-Vis absorption spectra of L and complex 1 are shown in FIG. 1. As can be seen from FIG. 1, the absorption peak of the Ni (II) complex is clearly different from that of the ligand H before coordination₂L。H₂The UV-Vis spectrum of L has distinct absorption peaks at 278 and 412nm, the absorption peak at 278nm is considered to be a π - π transition, while the absorption peak at 412nm is due to a C = N N- π transition. After Ni2+ coordination, the absorption peaks at 278 and 412nm disappear, a weak wide absorption peak appears at 334nm, and the new absorption peak can be assigned to have N₃O₂L ⟶ M charge transfer (LMCT) transition of the transition metal complex of the coordination sphere.

Ligand H is reacted with ethanol₂The concentration of L was fixed at 50 uM. Each addition of Ni to a dilute ligand solution (3 mL)²⁺Ions. When Ni is present²⁺/L^2-End point of titration was reached at = 1/1. In UV-vis titration experiments with Ni (II) complexes²⁺The increase in ion concentration increases the absorbance of the solution at-255 nm and-334 nm, while the absorbance at-278 nm and-412 nm decreases (figure 2). When Ni is added²⁺At 1 equivalent, the absorption reached the highest value. The UV-vis spectral titration shows that the metal ion (Ni) in the compound 1²⁺) With ligands (H)₂L) is 1: 1. the enhancement of the absorption peak at 334nm is due to the coordination of the metal ion with the ligand.

Since the binding of the ligand to the metal is as follows 1: 1, thus by 1/(A-A)₀) And 1/[ Ni ]²⁺]A linear fit is performed, by equation (1):

the association constant K = 2.5 × 10 was calculated³ M^-1(FIG. 3). The detection limit was calculated to be 17 μ M (fig. 4) using the simple formula LOD =3 σ/M, where "σ" is the standard deviation of the blank measurement and "M" is the slope of the linear calibration curve.

Fluorescence titration spectra (fig. 5) data (ethanol as solvent): first, ligand H is reacted with ethanol₂L was set at 400uM, and then Ni was added to the diluted ligand solution (3 mL) successively²⁺Ions. When Ni is present²⁺/L^2-=1/1, endpoint for titration was reached. Ligand H with increasing Ni (II) ion concentration₂The fluorescence spectrum of L shows a decreasing emission intensity of the solution. When the added Ni (II) ion reaches 1.0 equivalent, the fluorescence intensity of the solution is almost unchanged, and the same conclusion as that of the UV-vis titration experiment is reached. At the same time, non-halogenated ligand H is carried out₂L' in Ni²⁺By comparing the titration experiments with ions (FIG. 6), it is clear that the fluorescence change of the non-halogenated titration is smoother, while the halogenated fluorescence titration is in Ni²⁺/H₂L = 0.11-0.22 has a large mutation, indicating that the formation of the mononuclear complex in solution is accompanied by the formation of the trimer during this process, indicating that the Cl atom plays an important role in the formation of the trimer.

The crystal structure of the obtained product was determined: the best quality bulk crystal with dimensions of 0.10 x 0.18 x 0.36 cubic millimeters was selected and mounted on a CCD area detector diffractometer. Single crystal datasets were collected on a MoK alpha radiation (λ = 0.71073 a) and an Xcalibur Eos auto-diffractometer at 293(2) K. Integration and correction of Lorentz and polarization effect intensity was performed in cryslaispro software. The central nickel atom was determined by direct method and the remaining atoms were revealed sequentially by fourier synthesis. The full matrix method is used for F through an Olex2 software package²And (5) thinning. All non-H atoms are anisotropically refined in the final refinement. The position of the H atom being determined by calculation, -CH₂The C-H bond of the group is fixed at 0.99A in length and the C-H bond of the methyl group is fixed at 0.98A and allowed to rotate around the C-C bond, the aromatic C-H distance being 0.95A. Will be-CH₂-and-CH₃Of a hydrogen atom of_isoThe value is set to 1.5U_eq(C) U of another hydrogen atom_isoThe value is set to 1.2U_eq(C)。

TABLE 1 crystallographic data and Structure refinement parameters for the inventive example 1 complexes

Empirical formula	C₆₃H₆₃Ni₃Cl₁₂N₉O₆
		Formula weight	1643.66
Temperature/K	150(2)
		Crystal system	monoclinic
Space group	P2₁/n
		a/Å	10.5453(2)
b/Å	36.2658(9)
		c/Å	18.2268(5)
α/°	90
		β/°	100.6040(10)
γ/°	90
		Volume/Å³	6851.5(3)
Z	4
		ρ_calcg/cm³	1.526
μ/mm^-1	1.339
		F(000)	3097.0
Crystal size/mm³	0.10 ×0.18 × 0.36
		Radiation	MoKα (λ = 0.71073)
2Θ range for data collection/°	4.064 to 52.758
		Index ranges	-13 ≤ h ≤ 13, -45 ≤ k ≤ 45, -22 ≤ l ≤ 22
Reflections collected	97212
		Independent reflections	14008 [R_int = 0.0535, R_sigma = 0.0294]
Data/restraints/parameters	14008/0/841
		Goodness-of-fit on F²	1.042
Final R indexes [I>=2σ (I)]	R1 = 0.0549, wR2 = 0.1494
		Final R indexes [all data]	R1 = 0.0698, wR2 = 0.1620
Largest diff. peak/hole / e Å^-3	2.40/-1.19

The crystal structure of the single nucleus of the complex is shown in figure 7, and the crystal structure of the trimer is shown in figure 8. In monoclinic space group P2₁It is parsed and refined in/n, with the following unit pixel parameters: a = 10.5453(2), b = 36.2658(9) a, c = 18.2268(5) a, α = 90 °, β = 100.6040(10) ° γ = 90 °, unit cell having four formula units at 150K (Z = 4). The crystallographic data of the complex and the structural resolution and refinement details are shown in table 1.

Compound 1 is composed of three Ni^IIThe (3, 5-Cl-salmpn) units are connected by halogen bonds (Cl (4) · · Cl (9) = 3.289(1) A, Cl (5) · · Cl (7) = 3.879 (1)) C-H · H (C (13) -H (13) · · H (1MB) = 2.315 (0)), C-H · C (1M) -H (1MA) · · C (7) = 2.765 (1)), C (25) -H (25A) · · C (8) = 2.818 (0)), C (25) -H (25A) · · C (1L) = 2.853(0)) and C · O (25) · · O (4) = 3.076(1)), each of which is connected by a triangular bond, wherein each of the bonds exhibits a triangular arrangement^IIOne Ni (II) center and one 3, 5-Cl-salempn Saldmpn type ligand are present in the (3, 5-Cl-salempn) asymmetric unit. Each Ni^IIThe (3, 5-Cl-salempn) asymmetric unit, in which the Ni (II) atom is located in the center of the complex, cooperates with two oxygen atoms and three nitrogen atoms, exhibits overall a distorted triangular bipyramid geometry (τ = 0.619), with the Ni (N) bond being slightly longer than the Ni (1) O bond (Ni (1) N (8), Ni (1) N (14), Ni (1) N (16), Ni (1) O (3) and Ni (1) O (4) of 2.013(4), 2.087(4), 2.011(4), 1.978(3) and 1.975(3), respectively). As can be seen, trimer { [ Ni ]^II(3,5-Cl-saldmpn)]₃Three mononuclear Ni in^II(3, 5-Cl-salempn) are respectively located at [ 020]Z = 3/14, z = 5/14, z =1/2 positions in the plane.

The inventive complexes have bond lengths and bond angles in the normal range, a C-N bond length in the range of 1.271(6) -1.506(9), a C-O bond length in the range of 1.287(5) -1.296(5), a C-Cl bond length in the range of 1.729(5) -1.755(4), and a C-C bond length varying in the range of 1.362(7) -1.604 (12). The angular variation range of C-C-C is 114.0(4) -124.4(4) ° O-Ni-O is 142.18(13) -155.06(14) ° O-Ni-N is 88.59(14) -113.07(14) ° O-Ni-N is 88.74(17) -92.78(17) ° cis-N-Ni-N is 175.14(16) -179.32(15) ° trans-N is between 175.14(16) -179.32(15) ° trans-N.

Two adjacent tripolymers are connected through a halogen bond (Cl (1) · · Cl (8) = 3.319(1) A) to form a one-dimensional chain structure. The one-dimensional chain structure with the tripolymers as units is not arranged linearly, but is arranged in a vertically staggered manner with two adjacent tripolymers in opposite directions to form a special spiral chain structure induced by halogen bonds. Meanwhile, adjacent two spiral chains are connected together through C-H · · Cl (C (27) -H (27A) · · Cl (12) = 2.773(1) A, and C (20) -H (20A) · · Cl (16) = 2.884(1) A) to form a 2D layer. Furthermore, these 2D layered structures are connected together by C-H.Cl and C-H.C contacts to form a three-dimensional supramolecular network. The detailed intermolecular hydrogen bond and halogen bond geometries are listed in tables 2 and 3, respectively (all intermolecular/intramolecular interactions based on crystal structure were calculated using the PLATON program).

TABLE 2 geometric information of the hydrogen bonding of the complexes

D-H···A	D-H, Å	H···A, Å	D···A	D-H···A, deg
					C(1M)ⁱⁱ-H(1MA)ⁱⁱ···C(7)	0.990	2.765	3.572	139.08
C(13)ⁱ-H(13)ⁱ···H(1MB)ⁱⁱ	0.950	2.315	3.219	158.83
					H(25A)ⁱⁱ-C(25)ⁱⁱ···O(4)	0.980	3.076	2.891	69.99
C(25)ⁱⁱ-H(25A)ⁱⁱ···C(8)	0.980	2.818	3.378	117.04
					C(25)ⁱⁱ-H(25A)ⁱⁱ···C(1L)	0.980	2.853	3.616	135.39

Symmetrycode: (i) 1-x,-y,-z ; (ii) 1-x,-y,1-z; (iii) 2-x,1-y,1-z

Geometric structural information of halogen bond of epi 3 complex

D-X···A	D-X, Å	X···A, Å	D-X···A, deg
				C(34)-Cl(7)···Cl(5)ⁱ	1.744	3.879	102.67
C(34)ⁱⁱ-Cl(9)ⁱⁱ···Cl(4)ⁱ	1.739	3.289	114.18

Symmetrycode: (i) 1-x,-y,-z ;

In conclusion, the complex of the present invention is composed of a special supramolecular trimer structure, and the halogen Cl atom plays an important role in the formation of the trimer.

Secondly, testing the pH stability and the luminescence property of the Saldmpn type Ni (II) complex:

the Saldmpn type Ni (II) complex has unique fluorescence property, so that the Saldmpn type Ni (II) complex has potential application prospect in the fields of chemical sensors and photochemistry. Different Saldmpn type complexes have different pH stabilities, and the stable pH range of the complex is detected by the invention.

1. The complex was added to ethanol solutions of different pH and the fluorescence intensity and emission peak position were recorded and compared as shown in fig. 9.

In an environment of pH =5, the fluorescence intensity of the complex (400 μ M) was weak (I)_ob=1×10⁴) And when the pH value is increased by one unit to pH =6, the fluorescence intensity of the complex is very strong, and I is achieved_ob=1×10⁵A 10-fold significant increase compared to pH =5, and as the pH continues to rise, there is no significant change in the fluorescence intensity of the complex, an unusual phenomenon. Thus, the complex was compared to H in a pH =6 environment₂The fluorescence intensity of L is shown in FIG. 10. It can be said that the reason why the fluorescence intensity of compound 1 changes so much from pH =5 to pH =6 is because the trimer is present in OH^-Rapidly decompose to L under ambient conditions^2-And Ni²⁺It can be said that the trimer is extremely sensitive to pH, and when pH is decreased from pH =6 to pH =5, the fluorescence intensity decreases, L^2-And Ni²⁺Rapidly recombining into trimers. The method can adjust the fluorescence intensity in a mild and weakly acidic environment, and keep the structure unchanged under different fluorescence behaviors.

2. To verify the pH>5 hours strong fluorescence, measured by relative method₂-χ-L，Ni-L，H₂-quantum yield of L. As shown in FIG. 11, [ Ni-chi-L ] was observed at pH6]The quantum yield (8.64%) of the product is obviously higher than that of the ligand H₂The quantum yield of χ -L (1.58%), indicates that the abnormal change in fluorescence intensity results from the conversion of trimer to monomer, rather than the formation of free ligand. At the same time, we have found the non-halogenated isomer [ Ni-L ]](Ni-L:0.048%) was also lower than 1 (FIG. 11b), indicating that substitution of chlorine atoms in the Saldmpn-type ligand generally enhanced the fluorescence quantum yield of the Saldmpn-type complex, consistent with theoretical calculations.

3. To explore the differences in enhancement of different metals by halogenated Schiff base ligands over the pH range of 5-6, we compared a series of salempn-based ligands^2-(Mn²⁺、Fe³⁺、Ni²⁺、Cu²⁺、Ag⁺、Al³⁺、Bi³⁺、Ca²⁺、Cr³⁺、K⁺、Li⁺、Mg²⁺、Na⁺、Zn²⁺、Sr²⁺) The fold change of the complex of (a). As shown in FIG. 12, it can be seen that although the Saldmpn type complex showed the same enhancement tendency in the change of pH5-6, the fold change of fluorescence intensity of the Ni complex was significantly higher than that of the other metal complexes, indicating that [ Ni-chi-L ]]₃The highest sensitivity and discrimination for pH5-6 makes it an ideal candidate for a pH probe in this range.

4. In order to explore the rapid, simple and convenient real-time colorimetric pH sensing through [ Ni-chi-L ], image research based on a mobile phone imaging system is developed, and because the equipment is portable, the experimental procedure can be greatly simplified, and the detection cost is reduced. To this end, 400. mu.L [ Ni-chi-L ] was added to sample solutions of different pH and the samples were placed in fixed positions in the viewing chamber with a 20W white LED as the light source (FIG. 13 a). The RGB values are extracted by the color analysis app on the phone and plotted as RGB-pH values (fig. 13 b). As the pH increases, the color gradually changes from colorless to yellow, resulting in a significant decrease in the complementary color blue to yellow, so that the pH can be calculated quantitatively.

Slope fitting is performed on the blue channel (red line in fig. 13 c), and a fitting formula can be used to obtain the blue channel value through the imaging system to accurately calculate the pH of the unknown solution.

Thirdly, detecting the reversibility and stability of the Saldmpn type Ni (II) complex

1. Reversible detection of trimer: alternatively add 1X 10 to ethanol solution of compound (400uM)^－8umol/ml NaOH and HCl aqueous solution, pH environment between 5-6, the resulting spectrum is shown in FIG. 14.

As a result: there was no significant change in fluorescence intensity after 6 cycles (FIG. 14); more than 90% of the initial signal intensity was maintained after 30 cycles.

2. And (3) detecting the stability of the tripolymer: samples of the conjugate containing pH =5 and 6 were placed in a cuvette and exposed to a daylight environment, and the fluorescence intensity of samples of the conjugate at pH =5 and 6 was measured every 4 or 8 hours.

As a result: as shown in fig. 15, the obtained fluorescence intensity remained stable for more than two days, indicating that the complexes and ligands of the two forms were stable in the pH =5 and 6 environments, respectively, for more than 48 hours without intensity change.

As a result, the fluorescence intensity of the complex was very weak (I)_ob=1×10⁴) However, when the pH was increased to pH =6, the fluorescence intensity significantly increased by 10-fold (I)_ob=1×10⁵). By reaction with ligand H₂Comparison of L, due to trimer at pH>Decomposition to L in the Environment of 6^2-And Ni²⁺The result is. Stability tests show that the fluorescence intensity of the complex is stabilized for more than 48h, so that the potential logic gate unit has good reversibility (FIG. 16 is a potential logic gate circuit).

Claims

1. The application of a Saldmpn type nickel (II) halide complex serving as a pH sensor based on a smartphone imaging system, wherein the molecular formula of the complex is { [ Ni ]^II(3,5-Cl- saldmpn)]}₃(1) Wherein 3, 5-Cl-salempn = N, N '-bis (3, 5-dichlorosalicylaldehyde) -N, N' -bis (3-aminopropyl) methylamine is monoclinic, P2₁A/n space group, the asymmetric unit of which is composed of three neutral Ni^II(3, 5-Cl-salempn) is formed by connecting multiple weak interactions in which halogen bonds participate, and each Ni^IIThe (3,5-Cl-salmen) asymmetric unit has a Ni (II) center and a 3,5-Cl-salmenSaldmpn type ligand; the asymmetric unit is composed of three crystallographically independent neutral Ni^II(3,5-Cl-salmen), the geometry of Ni1, Ni2 is close to that of a trigonal bipyramid, the geometry of Ni3 is of a regular tetrahedron, where τ 1=0.534, τ 2= 0.619, τ 3= 0.333; the pH values for the formation and separation of the supramolecular trimer of the complex are 5 and 6, respectively.

2. Use of a Saldmpn-type nickel (II) halide complex of the formula { [ Ni ] as a logic gate unit for the creation of a suppressor logic device^II(3,5-Cl- saldmpn)]}₃(1) Wherein 3, 5-Cl-salempn = N, N '-bis (3, 5-dichlorosalicylaldehyde) -N, N' -bis (3-aminopropyl) methylamine is monoclinic, P2₁A/n space group, the asymmetric unit of which is composed of three neutral Ni^II(3, 5-Cl-salempn) is connected by multiple weak interactions involving halogen bonds, each Ni^II(3,5-Cl-salmen) asymmetric unit with a Ni (II) center and a 3,5-Cl-salmenSaldmpn type ligand; the asymmetric unit is composed of three crystallographically independent neutral Ni^II(3,5-Cl-salmen), the geometry of Ni1, Ni2 is close to that of a trigonal bipyramid, the geometry of Ni3 is of a regular tetrahedron, where τ 1=0.534, τ 2= 0.619, τ 3= 0.333; the pH values for the formation and separation of the supramolecular trimer of the complex are 5 and 6, respectively.

3. Use according to claim 2, for the construction of molecular inhibit logic gates based on the fact that the complexes differ by more than 15 times in their fluorescence intensity at concentrations of 400 μ M, pH =5 and 6, by weak H⁺And OH^-For input signals, the complex is used as a molecular logic sensing platform, and changes of fluorescence intensity at 521nm are used as output signals to represent '0' and '1' for construction.