CN114854037B - Cobalt (II) complex with semiconductor property and preparation method thereof - Google Patents

Abstract

The invention discloses a cobalt (II) complex with semiconductor properties and a preparation method. The chemical formula of the complex is [Co(C ₁₈ H ₁₂ S ₂ N ₂ )(C ₉ H ₄ O ₆ )(H ₂ O) ₂ ] _{n .} Thiophene is the main ligand, 1,2,4-benzenetricarboxylic acid is the auxiliary ligand, Co ²⁺ is the metal ion, and it is prepared under solvothermal conditions. Experimental results show that the cobalt (II) complex has semiconducting properties at room temperature. The preparation method of the invention is simple, low in cost, high in yield, high in purity and good in reproducibility, and has potential application value in the semiconductor field.

Description

A cobalt (II) complex with semiconductor properties and preparation method thereof

Technical Field

The invention relates to the field of metal complexes, and in particular to a cobalt (II) complex with semiconductor properties and a preparation method thereof.

Background Art

Metal coordination polymers, referred to as metal complexes, are a type of solid crystalline materials assembled by organic ligands and metal ions or metal cluster units through coordination bonds. They have the characteristics of high porosity, low density, large specific surface area, regular pores, adjustable and modifiable pore size, and topological structure diversity and tailorability. They are another important new type of porous material besides zeolites and carbon nanotubes. In recent years, they have been widely used in gas storage and separation, catalysis, fluorescence, magnetism, small molecule recognition, and energy storage. Compared with the above traditional properties, the research on the optoelectronic properties of metal complexes is not very sufficient. Conjugated thiophene compounds are a very important and useful class of compounds in the preparation of electronic and optical materials because of their good electron transfer ability and rigid structure. However, judging from the reported metal complexes, metal complexes with conjugated thiophene compounds as ligands have been reported very few so far. Therefore, using conjugated thiophene compounds as ligands to prepare metal complexes with semiconductor properties can not only provide more metal complexes with novel structures in the field of coordination chemistry, but also expand the research scope of semiconductor functional materials. Therefore, designing and synthesizing metal complexes with stable structures, simple synthesis and semiconductor properties is an important research content of coordination chemistry and functional materials.

Summary of the invention

The object of the present invention is to provide a cobalt (II) complex having semiconductor properties.

Another object of the present invention is to provide a method for preparing the above-mentioned cobalt (II) complex having semiconductor properties, which has simple steps.

To achieve the above purpose, the technical solution adopted by the present invention is as follows:

In a first aspect, the present invention provides a cobalt (II) complex with semiconductor properties, wherein the complex is prepared by a solvothermal method using Co ²⁺ as a metal ion, 5,5'-bipyridylbithiophene (bpbp) as a main ligand, and 1,2,4-benzenetricarboxylic acid (H ₃ bta) as an auxiliary ligand; the chemical formula of the cobalt (II) complex is shown in Formula 1:

In a second aspect, the present invention also provides a method for preparing the above-mentioned cobalt (II) complex having semiconductor properties, comprising the following steps:

S1. Mixing ligand 5,5'-bipyridylbithiophene (bpbp), 1,2,4-benzenetricarboxylic acid (H ₃ bta) and metal cobalt salt at a molar ratio of (1-1.5):(1-1.5):1 at room temperature to obtain a mixture;

S2. adding an organic solvent to the mixture obtained in step S1 to obtain a suspension I, and ultrasonically dispersing the suspension I;

S3. Add deionized water to the suspension Ⅰ treated in step S2 to obtain a suspension Ⅱ;

S4. The suspension treated in step S3 is heated to react at 80°C-100°C;

S5. After the reaction is completed, the mixture is naturally cooled to room temperature and filtered to obtain the cobalt (II) complex.

Preferably, the metal cobalt salt in step S1 is selected from one or more of cobalt nitrate, acetate, carbonate, perchlorate or chloride.

More preferably, the metal cobalt salt in step S1 is selected from one or more of cobalt nitrate, acetate and chloride.

Preferably, the organic solvent in step S2 is selected from one or more of methanol, N,N'-dimethylformamide or N,N'-dimethylacetamide.

Preferably, in step S2, the ultrasonic power is 300 W, and the ultrasonic time is 15 to 30 minutes.

Preferably, the volume ratio of the deionized water in step S3 to the organic solvent in step S2 is 1:(1-4).

Preferably, the reaction time of the heating reaction in step S4 is 2 to 4 days.

Compared with the prior art, the present invention has the following beneficial effects:

1. The preparation method provided by the present invention is simple, low in cost, high in yield, high in purity and good in reproducibility;

2. The cobalt (II) complex obtained by the present invention has good semiconductor properties and can be applied in the semiconductor field.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a diagram of the coordination environment of the cobalt (II) complex prepared by the present invention;

FIG2 is a one-dimensional chain structure diagram of the cobalt (II) complex prepared by the present invention;

FIG3 is an XRD powder diffraction pattern of the cobalt (II) complex prepared by the present invention;

FIG4 is a solid UV-visible absorption spectrum of the cobalt (II) complex prepared by the present invention;

FIG5 is a Kubelka-Munk function diagram of the cobalt (II) complex prepared by the present invention.

DETAILED DESCRIPTION

The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1: Synthesis of Cobalt (II) Complex

1mmol Co(NO ₃ ) ₂ ·6H ₂ O, 1mmol 5,5'-bipyridylbithiophene (bpbp), and 1mmol 1,2,4-benzenetricarboxylic acid (H ₃ bta) were dispersed in 3mL N,N'-dimethylacetamide and mixed. The mixture was ultrasonically dispersed at room temperature for 15 minutes. Then, 3mL of deionized water was added to the mixture, and the mixture was transferred to a 15mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The reaction was carried out at 85°C for 3 days. After the reactor was naturally cooled to room temperature, a pink cobalt (II) complex was obtained by filtration with a yield of 56%. The chemical formula of the complex is [Co(C ₁₈ H ₁₂ S ₂ N ₂ )(C ₉ H ₄ O ₆ )(H ₂ O) ₂ ] _n , elemental analysis: C, 51.96; H, 3.26; N, 4.55%, C ₂₇ H ₁₉ CoN ₂ O ₈ S ₂ theoretical value: C, 52.01; H, 3.23; N, 4.49%. Infrared absorption spectrum data (KBr, cm ^-1 ): 3414 (w), 1682 (s), 1609 (vs), 1486 (w), 1441 (w), 1380 (s), 1280 (w), 1230 (m), 1066 (w), 1019 (w), 910 (w), 824 (w), 796 (m), 704 (w), 614 (w).

Structural characterization of cobalt(II) complexes:

(1) X-ray single crystal diffraction

Single crystals of suitable size were selected under a microscope and X-ray single crystal diffraction experiments were carried out at room temperature. X-ray single crystal diffraction data were measured on a Bruker Smart Apex II CCD diffractometer, using graphite monochromatized Mo Kα (λ=0.071073nm) radiation as the light source. The collected data were subjected to absorption correction by SADABS, and the crystal structure was solved by the direct method using the SHELXTL program. The coordinates of non-hydrogen atoms were successively determined in subsequent rounds of difference Fourier synthesis, and the coordinates and anisotropy parameters of all non-hydrogen atoms were refined by the least squares method based on ^F2 . All hydrogen atoms on carbon were obtained according to theoretical hydrogenation. The crystallographic data of the complex are shown in the following table.

Table 1 Crystallographic data of the complexes

^a R ₁ ＝Σ||F ₀ |–|F _c ||/Σ|F ₀ |, ^b wR ₂ ＝Σ[w(F ₀ ² –F _c ² ) ² ]/Σ[w(F ₀ ² ) ² ] ^1/2 ;where w＝1/[σ ² (F _o ² )+(aP) ² +bP],P＝(F _o ² +2F _c ² )/3

α＝80.8910(10)°，β＝97.491(3)°，γ＝88.1410(10)°；

T＝296(2)K，所述钴(II)配合物的晶体结构中最小不对称结构单元含有两个晶体学占有率为0.5的Co(II)离子、一个5,5'-二吡啶联二噻吩(bpbp)配体、一个部分脱质子的1,2,4-苯三甲酸(Hbta^2-)配体和两个配位水分子。其中Co1与两个晶体学对称的5,5'-二吡啶联二噻吩(bpbp)的两个氮原子、两个晶体学对称的部分脱质子的1,2,4-苯三甲酸(Hbta^2-)的四个氧原子配位，Co2与两个晶体学对称的5,5'-二吡啶联二噻吩(bpbp)的两个氮原子、四个晶体学对称的配位水分子配位，形成如图1所示的配位模式，并通过与5,5'-二吡啶联二噻吩(bpbp)桥联作用形成如图2所示的一维链状结构。The chemical formula of the cobalt (II) complex is [Co(C ₁₈ H ₁₂ N ₂ ) ₂ (C ₉ H ₄ O ₆ )(H ₂ O) ₂ ] _n , belongs to the triclinic system, the space group is P-1 (No. 2), and the unit cell parameters are:

α=80.8910(10)°, β=97.491(3)°, γ=88.1410(10)°;

T = 296 (2) K, the smallest asymmetric structural unit in the crystal structure of the cobalt (II) complex contains two Co (II) ions with a crystallographic occupancy of 0.5, a 5,5'-bipyridylbithiophene (bpbp) ligand, a partially deprotonated 1,2,4-benzenetricarboxylic acid (Hbta ^2- ) ligand and two coordinated water molecules. Among them, Co1 is coordinated with two nitrogen atoms of two crystallographically symmetrical 5,5'-bipyridylbithiophene (bpbp) and four oxygen atoms of two crystallographically symmetrical partially deprotonated 1,2,4-benzenetricarboxylic acid (Hbta ^2- ), and Co2 is coordinated with two nitrogen atoms of two crystallographically symmetrical 5,5'-bipyridylbithiophene (bpbp) and four crystallographically symmetrical coordinated water molecules, forming a coordination mode as shown in Figure 1, and forming a one-dimensional chain structure as shown in Figure 2 through bridging with 5,5'-bipyridylbithiophene (bpbp).

(2) X-ray powder diffraction

An appropriate amount of the cobalt (II) complex of the present invention was selected and powder diffraction was measured on a Bruker D8 X-ray diffractometer at room temperature. The test results are shown in FIG3 . The experimental spectrum and the simulated spectrum are well consistent, indicating that the synthesized complex is pure phase.

(3) Solid UV-Vis spectroscopy test

An appropriate amount of the cobalt (II) complex of Example 1 was selected and subjected to solid UV-visible spectroscopy test at room temperature using a Shimadzu UV-3600i Plus. The test results are shown in FIG4 . It can be seen that the cobalt (II) complex has a broad absorption band in the range of 300-600 nm, indicating that the material responds in the visible light range.

The diffuse reflectance data were converted into a Kubelka-Munk function to obtain the band gap value (E _g ) of the cobalt (II) complex of the present invention. As shown in FIG5 , E _g is 1.95 eV, which indicates that the cobalt (II) complex of the present invention can be used as a semiconductor material with potential applications.

Example 2: Synthesis of Cobalt (II) Complex

1mmol Co(CH ₃ COO) ₂ ·4H ₂ O, 1mmol 5,5'-bipyridylbithiophene (bpbp), and 1mmol 1,2,4-benzenetricarboxylic acid (H ₃ bta) were dispersed in 3mL methanol and mixed. The mixture was ultrasonically dispersed at room temperature for 15 minutes. Then, 5mL deionized water was added to the mixture, and the mixture was transferred to a 15mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The reaction was carried out at 100°C for 3 days. After the reactor was naturally cooled to room temperature, a pink cobalt (II) complex was obtained by filtration with a yield of 50%.

Example 3: Synthesis of Cobalt (II) Complex

1mmol CoCl ₂ ·6H ₂ O, 1mmol 5,5'-bipyridylbithiophene (bpbp), and 1mmol 1,2,4-benzenetricarboxylic acid (H ₃ bta) were dispersed in 3mL N,N'-dimethylformamide and mixed. The mixture was dispersed by ultrasonic at room temperature for 15 minutes. Then, 4mL deionized water was added to the mixture, and the mixture was transferred to a 15mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The reaction was carried out at 90°C for 3 days. After the reactor was naturally cooled to room temperature, a pink cobalt (II) complex was obtained by filtration with a yield of 46%.

Claims (6)

1. A cobalt (II) complex having semiconducting properties, characterized in that the complex is prepared by reacting Co ²⁺ Is prepared by a solvothermal method by taking 5,5' -bipyridine dithiophene as a main ligand and 1,2, 4-benzene tricarboxylic acid as an auxiliary ligand; the chemical formula of the cobalt (II) complex is shown as formula 1:

；

1 (1)

The preparation method comprises the following steps:

s1, ligand 5,5' -dipyridyl dithiophene, 1,2, 4-benzene tricarboxylic acid and metal cobalt salt are mixed according to the mol ratio (1-1.5): (1-1.5): 1, mixing to obtain a mixture;

s2, adding an organic solvent N, N' -dimethylacetamide into the mixture obtained in the step S1 to obtain a suspension I, and performing ultrasonic dispersion on the suspension I;

s3, adding deionized water into the suspension I treated in the step S2 to obtain a suspension II;

s4, heating the suspension II treated in the step S3 at the temperature of 80-100 ℃ for reaction;

s5, after the reaction is finished, naturally cooling to room temperature, and filtering to obtain the cobalt (II) complex.

2. A cobalt (II) complex having semiconducting properties according to claim 1, wherein the metallic cobalt salt in step S1 is selected from one or more of the nitrate, acetate, carbonate, perchlorate or chloride salts of cobalt.

3. A cobalt (II) complex having semiconducting properties according to claim 1, wherein the metallic cobalt salt in step S1 is selected from one or more of the nitrate, acetate and chloride of cobalt.

4. The cobalt (II) complex having semiconductor properties according to claim 1, wherein the ultrasonic power in step S2 is 300W and the ultrasonic time is 15 to 30 minutes.

5. The cobalt (II) complex having semiconductor properties according to claim 1, wherein the volume ratio of deionized water in step S3 to the organic solvent in step S2 is 1 (1-4).

6. The cobalt (II) complex having semiconductor properties according to claim 1, wherein the reaction time of the heating reaction in step S4 is 2 to 4 days.

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