CN112707938A

CN112707938A - Tetra-substituted bifluorenyliron compound and preparation method thereof

Info

Publication number: CN112707938A
Application number: CN202110014188.5A
Authority: CN
Inventors: 刘钢; 刘书智
Original assignee: Shanghai Jiao Tong University
Current assignee: Shanghai Jiao Tong University
Priority date: 2021-01-06
Filing date: 2021-01-06
Publication date: 2021-04-27

Abstract

The invention belongs to the technical field of organic synthesis, and particularly discloses a tetra-substituted bifluorenyliron compound and a preparation method thereof, wherein the tetra-substituted bifluorenyliron compound is specifically 2,2 ', 7, 7' -tetra-substituted bifluorenyliron, and the tetra-substituent is the same group of nitro, alkyl, aryl, aldehyde group, phenol ether group, alkyl ether group, amino and hydroxyl. The preparation method comprises the following steps: firstly, adding 2, 7-disubstituted fluorene, an alkaline catalyst and anhydrous tetrahydrofuran into a reaction container, fully stirring, and reacting for at least 15-45min in an air atmosphere under ice bath; slowly adding ferrous chloride, and continuously reacting for 4-8h at room temperature; and finally, extracting and purifying by using an organic solvent. The 2,2 ', 7, 7' -tetra-substituted bifluorene iron compound provided by the invention has diversity in structure and function, and simultaneously has higher space symmetry and conjugation, so that the compound has good electrical property and ultraviolet light absorption property.

Description

Tetra-substituted bifluorenyliron compound and preparation method thereof

Technical Field

The invention relates to the technical field of organic synthesis, in particular to a tetra-substituted bifluorenyliron compound and a preparation method thereof.

Background

The ferrocene compound is an important organic compound and has wide application in industries such as industry, agriculture, medicine, aerospace, energy conservation, environmental protection and the like. The ferrocene molecules have polarity, and iron atoms coordinate with two cyclopentadiene to form a sandwich structure with stable space. The ferrocene compound has high thermal stability, can not be decomposed within 400 ℃, also has high chemical stability, and is stable under the conditions of strong acid-base property, oxidation and hydrogenation. In addition, ferrocene compounds have high radiation resistance and are often used as ultraviolet absorbers. However, the traditional ferrocene compound has few substituted sites, is a mono-substituted compound in general, and has few di-substituted and more ferrocene compounds, so the structural diversity and the functional diversity of the ferrocene compound are greatly limited.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a tetra-substituted bifluorenyliron compound and a preparation method thereof.

The technical scheme of the invention is as follows:

a tetra-substituted bifluorenyliron compound has a structural formula as follows:

wherein R is₁、R₂、R₁′、R₂' is the same group of nitryl, alkyl, aryl, aldehyde group, phenol ether group, alkyl ether group, amido group and hydroxyl group.

The preparation method of the tetra-substituted bifluorenyliron compound comprises the following operation steps:

(1) adding 2, 7-disubstituted fluorene, an alkaline catalyst and anhydrous tetrahydrofuran into a dry reaction container, fully stirring, and reacting in an air atmosphere for at least 15-45min under ice bath;

(2) slowly adding ferrous chloride into the mixed system in the step (1), and continuously reacting for 4-8h at room temperature;

(3) and (3) extracting and purifying the product obtained in the step (2) by using an organic solvent.

Preferably, the following components are added in the amount of each 40-100ml of anhydrous tetrahydrofuran: 0.5-3mmol of 2, 7-disubstituted fluorene, 3-8mmol of alkaline catalyst and 0.5-6mmol of ferrous chloride.

Further preferably, the basic catalyst is any one or more of sodium hydride, potassium hydride, lithium aluminum hydride, n-butyllithium, and t-butyllithium.

More preferably, the organic solvent is any one or more of petroleum ether, dichloromethane, chloroform, ethyl acetate, benzene and its homologues.

Compared with the prior art, the 2,2 ', 7, 7' -tetrasubstituted bifluorenyliron synthesized by the method can be modified on a double-layer bifluorenyliron ring, so that a bifluorenyliron double-layer structure has four same or different substituent groups, and the bifluorenyliron compound has diversity in structure and function; because the 2,2 ', 7, 7' -tetra-substituted bifluorene iron has higher space symmetry and conjugation, the substitute has good electrical property and stronger ultraviolet light absorption property.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a general reaction formula for preparing tetra-substituted bifluorenyliron compounds according to the present invention;

FIG. 2 is a plot of cyclic voltammetry for the product 2,2 ', 7, 7' -tetranitrobifluoreneiron of example 1;

FIG. 3 is a graph showing the ultraviolet absorption spectrum of 2,2 ', 7, 7' -tetranitrobifluoreneiron product of example 1;

FIG. 4 is a plot of cyclic voltammetry for the product 2,2 ', 7, 7' -tetraaminobifluoreneiron of example 2;

FIG. 5 is a graph showing an ultraviolet absorption spectrum of 2,2 ', 7, 7' -tetraaminobifluoreneiron which is a product of example 2;

FIG. 6 is a plot of cyclic voltammetry for the product 2,2 ', 7, 7' -tetramethylbifluoreneiron of example 3;

FIG. 7 is a graph showing an ultraviolet absorption spectrum of 2,2 ', 7, 7' -tetramethylbifluoreneiron which is a product of example 3;

FIG. 8 is a plot of cyclic voltammetry for the product 2,2 ', 7, 7' -tetrahydroxybifluoreneiron of example 4;

FIG. 9 is a UV absorption spectrum of 2,2 ', 7, 7' -tetrahydroxybifluoreneiron product of example 4.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

1mmol of 2, 7-dinitrofluorene, 5mmol of sodium hydride and 80ml of tetrahydrofuran are respectively added into a reaction bottle, stirred for 30 minutes in ice bath, then added with 2mmol of ferrous chloride, and stirred for reaction for 6 hours at room temperature. Then, water quenching reaction is added, and the resultant is extracted by ethyl acetate in a separating funnel and dried in vacuum to obtain orange red 2,2 ', 7, 7' -tetranitrobifluorene iron.

Example 2

1.1mmol of 2, 7-diaminofluorene, 5.2mmol of lithium aluminum hydride and 85ml of tetrahydrofuran are respectively added into a reaction bottle, stirred for 15 minutes in ice bath, added with 2.2mmol of ferrous chloride and continuously stirred for reaction for 5 hours at room temperature. And then adding water to quench the reaction, extracting the product by using petroleum ether in a separating funnel, and drying the product in vacuum to obtain orange-red 2,2 ', 7, 7' -tetraamino-bifluorene iron.

Example 3

Respectively adding 0.5mmol of 2, 7-dimethylfluorene, 8mmol of n-butyllithium and 40ml of tetrahydrofuran into a reaction bottle, stirring for 45 minutes in an ice bath, then adding 0.5mmol of ferrous chloride, and continuously stirring for reaction for 4 hours at room temperature. Then, water quenching reaction was added, and the resultant was extracted with dichloromethane in a separatory funnel and dried under vacuum to obtain orange-red 2,2 ', 7, 7' -tetramethylbifluoreneiron.

Example 4

Respectively adding 3mmol of 2, 7-dihydroxyfluorene, 3mmol of tert-butyllithium and 100ml of tetrahydrofuran into a reaction bottle, stirring for 50 minutes in ice bath, then adding 6mmol of ferrous chloride, and continuously stirring for reaction for 8 hours at room temperature. Then, water quenching reaction is added, and the resultant is extracted by benzene in a separating funnel and dried in vacuum to obtain orange red 2,2 ', 7, 7' -tetrahydroxy bifluorene iron.

And performing cyclic voltammetry on the product obtained in the above embodiment, wherein in the test, in a three-electrode system constructed by taking a glassy carbon electrode as a working electrode, Ag/AgCl as a reference electrode and a platinum wire electrode as an auxiliary electrode, an acetonitrile solution of 0.1mol/L tetrabutyl ammonium hexafluorophosphate is used as an electrolyte solution, and nitrogen is introduced to remove oxygen for 30min for the test. 2,2 ', 7, 7' -tetranitrobifluoreneiron of example 1, as shown in FIG. 2: the initial potential is 0V, the highest potential is 2V, the lowest potential is-0.5V, the scanning rate is 0.1V/s, the scanning range is-0.5V- +2V, when scanning from 0 to +2V, 2,2 ', 7, 7' -tetranitrobifluorene iron is oxidized, the oxidation potential is +1.6V, when scanning from +2V to-0.5V, the oxidation product is reduced back to 2,2 ', 7, 7' -tetranitrobifluorene iron, and the reduction potential is + 1.7V. 2,2 ', 7, 7' -tetraaminobifluoreneiron of example 2, as shown in FIG. 4: the initial potential of the cyclic voltammetry test is 0V, the highest potential is +1.75V, the lowest potential is-1.75V, the scanning rate is 0.1V/s, the scanning range is-1.75V to +1.75V, when scanning from 0 to +1.75V, 2,2 ', 7, 7' -tetraaminobifluorene iron is oxidized, the oxidation potential is +0.7V, and when scanning from +1.75 to-1.75V, the oxidation product is reduced back to 2,2 ', 7, 7' -tetraaminobifluorene iron, and the reduction potential is + 0.8V. 2,2 ', 7, 7' -tetramethylbifluorenyliron of example 3, as shown in FIG. 6: the initial potential of the cyclic voltammetry test is 0V, the highest potential is +1.75V, the lowest potential is-1.75V, the scanning rate is 0.1V/s, the scanning range is-1.75V to +1.75V, when scanning from 0 to +1.75V, 2,2 ', 7, 7' -tetramethyl bifluorene iron is oxidized, the oxidation potential is +0.5V, and when scanning from +1.75 to-1.75V, the oxidation product is reduced, and the reduction potential is + 0.6V. 2,2 ', 7, 7' -tetramethylbifluorenyliron of example 4, as shown in FIG. 8: the initial potential of the cyclic voltammetry test is 0V, the highest potential is +1.2V, the lowest potential is-1.2V, the scanning rate is 0.1V/s, the scanning range is-1.2V to +1.2V, when scanning from 0 to +1.2V, 2,2 ', 7, 7' -tetramethyl difluorene iron is oxidized, the oxidation potential is +0.75V, when scanning from +1.2V to-1.2V, the oxidation product is reduced to 2,2 ', 7, 7' -tetramethyl difluorene iron, and the reduction potential is + 0.8V. The 2,2 ', 7, 7' -tetra-substituted bifluorenyliron structure has good space symmetry and conjugation, and four representative compounds of the structure can be subjected to electrochemical oxidation reduction, so that the structure has good electrical properties.

The products of the above examples were tested for uv absorption by dissolving the product in ethyl acetate and testing in a 10mm thick quartz cuvette. 2,2 ', 7, 7' -tetranitrobifluoreneiron of example 1, with a light scanning range of 250nm to 450nm, FIG. 3 shows that it has strong absorption at 350 nm; 2,2 ', 7, 7' -tetraaminobifluorene iron of example 2, the light scanning range is 190nm to 500nm, and fig. 4 shows that it has strong absorption to light at 260nm and 325 nm; 2,2 ', 7, 7' -tetramethylbifluorenyliron of example 3, the light scanning range was 240nm to 450nm, and fig. 7 shows that it has strong absorption at 280nm and 350 nm; 2,2 ', 7, 7' -tetramethylbifluoreneiron of example 4, which had a light scanning range of 300nm to 450nm, was strongly absorbed at 340nm as shown in FIG. 9. The 2,2 ', 7, 7' -tetra-substituted bifluorenyliron structure has good space symmetry and conjugation, and an ultraviolet absorption test shows that the structure has high ultraviolet absorption capacity and can be used as a novel light absorption material.

The invention is not to be considered as limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. a four-substituted iron difluorene compound is characterized in that: structural formula is:

Wherein, R ₁ , R ₂ , R ₁ ′, and R ₂ ′ are the same group of nitro group, alkyl group, aryl group, aldehyde group, phenolic ether group, alkyl ether group, amine group, and hydroxyl group.

2. the preparation method of the four-substituted iron difluorene compound as claimed in claim 1, is characterized in that: comprise the following operation steps:

(1) 2,7-disubstituted fluorene, basic catalyst and anhydrous tetrahydrofuran are added to a dry reaction vessel and fully stirred, and react in an air atmosphere for at least 15-45min under an ice bath;

(2) slowly add ferrous chloride to the mixed system of step (1), and continue to react for 4-8h under room temperature;

(3) Extract and purify the product obtained in step (2) with an organic solvent.

3. the preparation method of the tetra-substituted iron difluorene compound according to claim 2, is characterized in that: in the anhydrous tetrahydrofuran of every 40-100ml, the component of the amount of the following substance is added: 2,7-disubstituted Fluorene 0.5-3 mmol, basic catalyst 3-8 mmol, ferrous chloride 0.5-6 mmol.

4. the preparation method of the tetra-substituted difluorene iron compound according to claim 2, is characterized in that: described basic catalyst is sodium hydride, potassium hydride, lithium aluminum hydride, n-butyl lithium, tert-butyl lithium any one or more of them.

5. the preparation method of the four-substituted iron difluorene compound according to claim 2, is characterized in that: described organic solvent is petroleum ether, dichloromethane, chloroform, ethyl acetate, benzene and the homology of benzene any one or more of them.