Studies On Synthesis And Electrochemical Property Of Ferrocenyl Indenyl Multisubstituted Benzene Derivatives

Indenyl ring possesses special coordinated behavior and can form a variety of metal complexes. Ferrocenyl group has a strong electrochemical redox effect, which can be used for designing a sort of functional photoelectric materials. Therefore, the design and synthesis of functional compounds and complexes featuring indenyl and ferrocenyl groups will provide model compounds for the development and utilization of new molecular photoelectric materials. In recent years, multiferrocenyl aromatics have attracted rising attention because of their special molecular structures and interesting electrochemical and spectroscopic properties.The synthesis of multisubstituted benzene derivatives has been greatly reported. The main preparation methods for multisubstituted benzene derivatives are Suzuki and Negishi cross-coupling reaction. However, it is difficult to add various ferrocenyl units to a specific position on the benzene ring via Suzuki and Negishi cross-coupling reaction due to multi-step reactions and long reaction time. These disadvantages can be overcome and synthesis of multisubstituted benzene derivatives with different substituted positions on benzene ring achieved by one step [2+2+2] cycloaddition reaction. In this dissertation, some multisubstituted benzene derivatives with ferrocenyl and/or ferrocenylethynyl and indenyl substituted units have been synthesized by [2+2+2] cycloaddition reaction.The main works in the dissertation are as follows:1.（2-Trimethylsilylethynyl）indene（IndC≡CSiMe₃）, 2-Indenylacetylene（IndC≡CH）, ethynylferrocene（FcC≡CH） and 1,4-bis（ferrocenyl）butadiyne（Fc-C≡C-C≡C-Fc） were synthesized according to the literatures. The new catalyst cobalt cluster Co₂（CO）₆（μ₂-η²-C₉H₇-C≡CSiMe₃）（1） and Co₂（CO）₆（μ₂-η²-C₉H₇-C≡CH）（2） were prepared.2. Three new sterically crowded indenyl ferrocenyl ferrocenylethynyl multisubstituted benzene isomers 1- trimethylsilyl- 2- indenyl- 4,5- diferrocenyl- 3,6-diferrocenylethynylbenzene [1-SiMe₃-2-Ind-4,5-（Fc）2-3,6-（FcC₂）₂]C₆（3） and 1-trimethylsilyl- 2- indenyl- 4,6- diferrocenyl-3,5-diferrocenylethynylbenzene [1-SiMe₃-2-Ind-4,6-（Fc）2-3,5-（FcC₂）₂]C₆（4） and 1- trimethylsilyl- 2- indenyl- 3,5-diferrocenyl- 4,6- diferrocenylethynylbenzene [1-SiMe₃-2-Ind-3,5-（Fc）2-4,6-（FcC₂）₂]C₆（5） were synthesized by [2+2+2] cycloaddition reactions of 1,4-bis（ferrocenyl）butadiyne using cobalt cluster 1 as catalyst precursor. The cyclotrimerization byproduct [（Fc）₃（FcC₂）₃]C₆ of 1,4-bis（ferrocenyl）butadiyne has been detected by LC-MS. The acetylene ligand in cobalt cluster 1 is involved in the cycloaddition reaction and the framework of cobalt cluster in 1 play a role of catalyst.3. Two new indenyl ferrocenyl multisubstituted benzene isomers 1-trimethylsilyl-2-indenyl-3,5-diferrocenylbenzene [Ind（Fc）₂SiMe₃]C₆H₂（6） and 1-trimethylsilyl-2-indenyl-4,6-diferrocenylbenzene [Ind（Fc）₂SiMe₃]C₆H₂（7） was synthesized by [2+2+2] cycloaddition reactions of ethynylferrocene using cobalt cluster 1 as catalyst precursor. Meanwhile, the cyclotrimerization byproduct 1,2,4-triferrocenylbenzene（Fc）₃C₆H₃ of ethynylferrocene was seperated. The acetylene ligand in cobalt cluster 1 is involved in the cycloaddition reaction and the framework of cobalt cluster in 1 play a role of catalyst.4. The new indenyl ferrocenyl multisubstituted benzene derivatives 8 and 9 was synthesized by [2+2+2] cycloaddition reactions of ethynylferrocene using cobalt cluster 2 as catalyst precursor using toluene as solvent. The one of the compound is 1-indenyl-2,4-diferrocenylbenzene which is confirmed by NMR spectrum analysis. The other compound could be is 1-indenyl-3,5-diferrocenylbenzene. Meanwhile, the cyclotrimerization byproduct 1,2,4-triferrocenylbenzene（Fc）₃C₆H₃ of ethynylferrocene was seperated. The acetylene ligand in cobalt cluster 2 is involved in the cycloaddition reaction and the framework of cobalt cluster in 2 play a role of catalyst.5. All compounds 1-9 were characterized by FTIR, NMR, MS, UV, MP and element analysis. The crystal structures of compounds 1, 3, 4, 6 were determined by X-ray single crystal diffraction technique for the first time.6. The electrochemical property of compounds 3-6 was studied via cyclic voltammetry and square wave voltammetry. The results indicate that three or two reversible redox peaks of ferrocenyl moieties occurred in compounds 3-5 or compound 6, respectively. There was electronic communication between two ferrocenyl groups directly connected to benzene ring, and there was not electronic interaction between two ferrocenyl groups bridged ethynyl units in the compounds 3-5, which only one reversible redox peaks occured. The electronic communication between two ferrocenyl groups in compound 3 is stronger than that in compounds 4 and 5. The electronic interaction between two ferrocenyl groups in compound 6 is weakest.7. The relation of substituted positions to electrochemical properties in isomers of multisubstituted benzene derivatives was found, and the molecular structure of isomer 5 was deduced according to the electrochemical property difference between the compounds 4 and 5.