A spin crossover complex with aggregation-enhanced charge transfer properties and its preparation method and application

Abstract

The present invention discloses a spin crossover complex with aggregation-enhanced charge transfer characteristics, a preparation method and an application thereof. The chemical structure of the spin crossover complex is as follows, wherein A is an anion, including SCN‑, SeCN‑, N(CN)2‑, N3‑, etc.; the preparation process is obtained by reacting a ligand containing aggregation-enhanced charge transfer characteristics with a ferrous salt. The ferrous spin crossover complex with aggregation-enhanced charge transfer characteristics described in the present invention changes the ligand field strength by inducing charge transfer inside the ligand, thereby achieving regulation of the spin crossover behavior, providing a new mode of regulating spin crossover. The ferrous spin crossover complex with aggregation-enhanced charge transfer characteristics is simple to synthesize and has stable performance, and has great application prospects in molecular electronic devices such as information storage, molecular switches, and molecular displays. #imgabs0#

Description

Technical Field

[0001] The invention relates to a spin-crossing material and a preparation method and application thereof, and in particular to a spin-crossing complex with aggregation-enhanced charge transfer characteristics and a preparation method and application thereof. Background Art

[0002] The essence of spin crossover is 3D 4 -3d 7 The first transition metal ion of the electronic configuration has two electronic configuration modes in the octahedral coordination field: high spin state and low spin state. Spin crossover materials will not have any kind of fatigue effect, and the spin crossover phenomenon can be repeated as needed without changing the material itself. This excellent property makes spin crossover materials have attractive application prospects in the fields of new information storage devices, molecular switches, sensor devices, detection devices, etc.

[0003] Charge transfer inside the ligand. This transition mainly involves ligands with conjugated systems. These ligands are prone to low-energy π-π* transitions, such as pyridines and phens. When organic zwitterions are used as ligands, the ligands themselves can contain both donor and acceptor sites, and aggregation-enhanced charge transfer will occur. The spin-crossing complexes reported so far are mainly Fe(II) and Fe(III) compounds, and a few appear in Co(II) systems. By inducing charge transfer inside the ligand to change the field strength of the ligand, the electronic state of the ferrous iron will be affected, and then the high and low spins of the ferrous iron will be affected, thereby achieving the regulation of the spin-crossing behavior, providing a new mode of regulating spin-crossing. Summary of the invention

[0004] Purpose of the invention: The present invention aims to provide an effective spin-crossing complex with ligand internal aggregation-enhanced charge transfer characteristics, demonstrating a new mode of regulating spin crossing; another purpose of the present invention is to provide a method for preparing the spin-crossing complex; another purpose of the present invention is to provide an application of the spin-crossing complex in molecular electronic devices.

[0005] Technical solution: The spin cross complex with aggregation-enhanced charge transfer characteristics of the present invention is formed by a ligand with internal charge transfer characteristics coordinated to a ferrous ion. The chemical structure of the spin cross complex is as follows:

[0006]

[0007] Wherein, A is an anion.

[0008] Furthermore, A is SCN-, SeCN-, N(CN)2- or N3-.

[0009] The method for preparing the spin crossover complex with aggregation-enhanced charge transfer characteristics comprises the following steps: reacting a ligand with aggregation-enhanced charge transfer characteristics and a ferrous salt in an alcohol solution:

[0010] (1) Ligand C 38 H 34 N8S synthesis: 1,10-phenanthroline-5,6-dione and 4,7-bis(4-(diethylamino)phenyl)benzo[c][1,2,5]thiadiazole-5,6-diamine were heated to obtain a dark green ligand powder;

[0011] (2) dissolving the above ligand in an alcohol solution to form a green solution a; adding ascorbic acid to the FeA2 alcohol solution to form a colorless solution b; slowly adding solution b dropwise to solution a, reacting in a reactor to obtain a gray-black solution, and centrifugally drying to obtain a gray-black complex powder;

[0012] The reaction formula of the preparation method is as follows:

[0013]

[0014] Furthermore, the alcohol solution in step (2) is methanol or ethanol; the molar ratio of the ligand to the ferrous ion is 2:1; the reaction temperature is 120-140°C, and the reaction time is 8-10h.

[0015] The spin crossover complex with aggregation-enhanced charge transfer characteristics of the present invention can be applied to molecular electronic devices such as information storage, molecular switches, and molecular displays.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The spin-crossing complex is a complex with excellent properties and stable performance, which demonstrates a new mode of regulating spin crossing and can realize spin crossing behavior at room temperature; (2) The preparation method is simple and flexible, and the ligand can be coordinated with a variety of inorganic ferrous substances of the same type; (3) The spin-crossing complex with aggregation-enhanced charge transfer characteristics described in the present invention can be applied to molecular electronic devices such as information storage, molecular switches, and molecular displays. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The spin cross complexes Fe(SCN)2(C 38 H 34 Liquid UV-visible absorption spectrum of N8S)2. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0019] Example 1

[0020] Spin cross-linked complex Fe(SCN)2(C 38 H 34 The preparation method of N8S)2, wherein the selected ferrous salt is Fe(SCN)2, comprises the following steps:

[0021] S1. Dissolve 0.2 mmol of ligand in 20 ml of methanol solution in a beaker to obtain a green solution;

[0022] S2. Dissolve 0.1mmol Fe(ClO4)2·6H2O in 10ml methanol solution in a beaker, dissolve 0.2mmol KSCN in 10ml methanol solution in a beaker, add 0.1g ascorbic acid to prevent oxidation, protect with nitrogen, stir and react for 20min, filter to obtain colorless Fe(SCN)2 solution;

[0023] S3. The solution in step 2 was slowly added dropwise to the solution in step 1, and the reaction was carried out in a reactor at 120°C for 10 hours to obtain a gray-black solution;

[0024] S4. The gray-black solution obtained above was centrifuged and dried to obtain gray-black Fe(SCN)2(C 38 H 34 N8S)2 complex powder.

[0025] The aggregation-induced charge transfer performance was investigated. The specific investigation process is as follows: Fe(SCN)2(C 38 H 34 N8S)2 was dissolved in DMF. Different amounts of water were added to the solution. The UV-visible absorption spectrum changed with the water ratio. Figure 1 As shown, it was observed that after adding water, the aggregation-enhanced charge transfer-induced transition from low-spin to high-spin electronic state was achieved. It can be seen that the spin crossover complex obtained by the method of the present invention is convenient for practical application and can be applied to molecular electronic devices such as information storage, molecular switches, and molecular displays.

[0026] Example 2

[0027] Spin cross-linked complex Fe(SeCN)2(C 38 H 34 The preparation method of N8S)2, wherein the ferrous salt selected is Fe(SeCN)2, comprises the following steps:

[0028] S1. Dissolve 0.2 mmol of ligand in 20 ml of ethanol solution in a beaker to obtain a green solution;

[0029] S2. Dissolve 0.1mmol Fe(ClO4)2·6H2O in 10ml ethanol solution in a beaker, dissolve 0.2mmol KSeCN in 10ml ethanol solution in a beaker, add 0.1g ascorbic acid to prevent oxidation, protect with nitrogen device, stir and react for 20min, filter to obtain Fe(SeCN)2 solution;

[0030] S3. The solution in step 2 was slowly added dropwise to the solution in step 1, and the reaction was carried out in a reactor at 120°C for 10 hours to obtain a gray-black solution;

[0031] S4. The gray-black solution obtained above is centrifuged and dried to obtain a gray-black complex powder.

[0032] Example 3

[0033] Spin cross-linked complex Fe[N(CN)2]2(C 38 H 34 The preparation method of N8S)2, wherein the ferrous salt is Fe[N(CN)2]2, comprises the following steps:

[0034] S1. Dissolve 0.2 mmol of ligand in 20 ml of ethanol solution in a beaker to obtain a green solution;

[0035] S2. Dissolve 0.1mmol Fe(ClO4)2·6H2O in 10ml ethanol solution in a beaker, dissolve 0.2mmol NaN(CN)2 in Fe[N(CN)2]2 in 10ml ethanol solution in a beaker, add 0.1g ascorbic acid to prevent oxidation, protect with nitrogen device, stir and react for 20min, filter to obtain Fe[N(CN)2]2 solution;

[0036] S3. The solution in step 2 was slowly added dropwise to the solution in step 1, and the reaction was carried out in a reactor at 120°C for 8h to obtain a gray-black solution;

[0037] S4. The gray-black solution obtained above is centrifuged and dried to obtain a gray-black complex powder.

[0038] Example 4

[0039] Spin cross-linked complex Fe(N3)2(C 38 H 34 The preparation method of N8S)2, wherein the ferrous salt selected is Fe(N3)2, comprises the following steps:

[0040] S1. Dissolve 0.2 mmol of ligand in 20 ml of methanol solution in a beaker to obtain a green solution;

[0041] S2. Dissolve 0.1mmol Fe(ClO4)2·6H2O in 10ml methanol solution in a beaker, dissolve 0.2mmol NaN3 in 10ml methanol solution in a beaker, add 0.1g ascorbic acid to prevent oxidation, protect with nitrogen device, stir and react for 20min, filter to obtain Fe(N3)2 solution;

[0042] S3. The solution in step 2 was slowly added dropwise to the solution in step 1, and the reaction was carried out in a reactor at 120°C for 8h to obtain a gray-black solution;

[0043] S4. The gray-black solution obtained above is centrifuged and dried to obtain a gray-black complex powder.

Claims

1. A spin crossover complex having aggregation enhanced charge transfer properties, characterized in that: The chemical structure of the spin cross complex is as follows: Among them, A is SCN-.

2. A method for preparing the spin crossover complex with aggregation enhanced charge transfer properties according to claim 1, characterized in that: The method comprises reacting a ligand having aggregation-enhanced charge transfer properties with a ferrous salt in an alcohol solution, and comprises the following steps: (1) Ligand C 38 H 34 N8S synthesis: 1,10-phenanthroline-5,6-dione and 4,7-bis(4-(diethylamino)phenyl)benzo[c][1,2,5]thiadiazole-5,6-diamine were heated to obtain a dark green ligand powder; (2) The above ligand is dissolved in alcohol to form a green solution a; ascorbic acid is added to the FeA2 alcohol solution to form a colorless solution b; solution b is slowly added dropwise to the green solution a, reacted in a reactor to obtain a gray-black solution, and centrifuged and dried to obtain a gray-black complex powder; the reaction formula is as follows: 。 3. The method for preparing a spin crossover complex having aggregation enhanced charge transfer properties according to claim 2, characterized in that: The alcohol solution in step (2) is methanol or ethanol.

4. The method for preparing a spin crossover complex having aggregation enhanced charge transfer properties according to claim 2, characterized in that: The molar ratio of the ligand to the ferrous ion in step (2) is 2:

1.

5. The method for preparing a spin crossover complex having aggregation enhanced charge transfer properties according to claim 2, characterized in that: The reaction temperature in step (2) is 120-140°C and the reaction time is 8-10 h.

6. Use of the spin crossover complex with aggregation enhanced charge transfer properties as claimed in claim 1 in molecular electronic devices.

Images