Synthesis of ortho-diferrocenylbenzene with cobalt clusters as reaction precursors: Crystal structure and electrochemical properties

Five new ortho-diferrocenylbenzene derivatives, 1,2-diferrocenyl-4,5-dimethylbenzene (2), 1,2-diferrocenyl-4,5-diphenylbenzene (3), 1,2-diferrocenyl-4,5-ditrimethylsilylbenzene (4), 1,2-diferrocenyl-3,4,5,6-tetramethylbenzene(5), and 1,2-diferrocenyl-3,4,5,6-tetraphenyl -benzene (6), were synthesized through the cycloaddition reactions of alkynes with the cobalt cluster Co-2(CO)(6)(mu(2)-alkyne) as reaction precursors, and characterized by elemental analysis, FT-IR, NMR, and MS. The molecular structures of compounds (2-6) were identified using single-crystal X-ray diffraction, and the electron interactions between two ferrocenyl units of each of the five compounds were investigated using cyclic voltammetric techniques. The results of electrochemical experiment indicated that the charge density of the aryl bridge is the key factor that influences electron communications between two ferrocenyl units. (C) 2012 Elsevier Ltd. All rights reserved.