Study On Synthesis,Electlfochemistry And In-situ FTIR Spectroelectrochemistry Of Bisferrocenyl Derivatives

Ferrocenyl derivatives is a new type of organic metal compounds. Due to its unique nature in electronchemistry, optical and electromagnetic, it is of great value in studying the basic theory of optical materials, molecular devices, molecular wires and bio-sensor. Besides, it also has extensive application prospect in the aspects mentioned above. Firstly, the recent research in designing, synthesis and application of bisferrocenyl derivatives was summarized. Secondly, two series of bisferrocenyl derivatives were synthesized and characterized by FTIR,1H NMR, MS. Finally, electrochemical properties were studied by CV and DPV, electrochemical properties and in situ infrared spectroelectrochemistry information were investigated by combining the in situ FTIR and the relationship between the constructure of bridged bisferrocenyl derivatives and the electron transfer mechanism were explored by means of DCVAs, numerical simulation of electrochemical processes and DFC, which supplied theoretical and experimental basis for designing and synthesizing new types of functional molecular materials.1. Two series of bridged bisferrocenyl derivatives were synthesized by means of esterification reaction and condensation reaction. One series was single carbon bridged bisferrocenyl derivatives and the other was bridged benzene bisferrocenyl derivatives. These compounds were characterized by means of FTIR, MS and NMR. The UV-Vis and Raman spectrum of these compounds were also studied.2. The crystal research of single carbon bridged bisferrocenyl derivatives (1-5). Five types of single carbon bridged bisferrocenyl derivatives were obtained from the experiment. Through the single-crytal structure analysis, we found that the bond angle of Fc-C-Fc of single carbon bridged bisferrocenyl derivatives (1-5) varied with the contribution of the donor-acceptor groups of substitutes on benzene. The shorter the distance between the two Fc group was, the smaller the dihedral angles of Cp-ring plane of two-Fc were, the stronger the electron communication was. In addition, we studied the electronic distribution, orbital energy and molecular transition of these five compounds using TD-DFT. The result showed that HOMO and HOMO-1mainly concentrated in Fc groups, while LUMO mainly concentrated in benzene.3. Electrochemical properties and electron transfer mechanism were invested by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The result shows the single carbon bridged bisferrocenyl derivatives(1-8) clearly exhibit two pairs of reversible redox peaks. The oxidation potential value of compound7was more positive than others, which was mainly due to the electron withdrawing effect of the carbonyl group is stronger than its conjugation. Compounds1-5were contrasted and the result showed the potential shift of these compounds relied on the electron withdrawing effect of substitutes on benzene of single carbon bisferrocenyl derivatives. The stronger the electron withdrawing effect was, the more positive the shift was. There was considerably more positive of compound3, due to the p-trifluoromethyl of benzene. For the other series of bisferrocenyl carboxylate benzene, the potential shift of them depended on the electron withdrawing effect of the bridged groups. The ester group caused the electron cloud density to reduce and made the oxidation more difficult. The potential shift of1,4-bis(2-ferrocene carboxylate)-2’-methylbenzene was more negative than other compounds, which showed that the methyl group of benzene not only caused the asymmetric of these compounds, but also caused the negative shift due to the impact of steric hindrance.4. The electrochemical redox process of the bisferrocenyl derivatives in CH2CI2was studied by means of in situ rapid scan FTIR spectroelectrochemistry. Firstly we studied the single carbon bisferrocenyl derivatives (1-8) by using in situ rapid scan FTIR spectroelectrochemistry. Although we didn’t find the variation of intermediates, the result showed that their electron transfer mechanism were two consecutive one-electron steps. Secondly, we studied the bisferrocenyl bridged benzene derivatives (9-12) by using in situ rapid scan FTIR spectroelectrochemistry and the result showed that in this process, no intermediate was found in other compounds except that in compound9and12the appearance and disappearance of the intermediates during oxidation and reduction process could be easily observed. In combination with in situ rapid scan FTIR spectroelectrochemistry, the oxidation and reduction was conducted by means of DCVA and concerning electrochemical process was obtained. The result shows that compound9and12were two consecutive one-electron steps. On the basis of the research above, it could be concluded that the electron transfer mechanism of these compounds9-12were two consecutive one-electron steps.5. Numerical simulation of electrochemical processes can provide very important information about some important references of electrochemical reaction. We simulated the electrochemical behavior of the eight kinds of single-carbon bridge bisferrocenyl derivatives. Through the simulation, we found that the electron transfer mechanism of these compounds exhibited a two-step process, during which the main impact included the kinetics constant and resistors.