1,1′-bis(dimethylvinylsilyl)ferrocene as a two-directional core for the construction of homo- and heterometallic systems

The divinyl derivative Fe[(eta(5)-C5H4)(Me2SiCH=CH2)](2) (1), prepared by the low-temperature reaction of 1, 1'-dilithioferrocene.TMEDA with ClSiMe2(CH=CH2), has been used as a readily functionalizable core unit for the synthesis of multimetallic systems. The hydrosilylation reaction of 1 with Cl2MeSiH and Ph2MeSiH provides the tetrafunctional ferrocenes Fe[(eta(5)-C5H4)(SiMe2(CH2)(2)SiMeCl2)](2) (2) and Fe[(eta(5)-C5H4)(SiMe2(CH2)(2)SiMePh2)](2) (5), which after reaction with Fe(eta(5)-C5H4Li)(eta(5)-C5H5) and Cr(CO)(6), respectively, afforded the pentametallic molecules Fe[(eta(5)-C5H4)(SiMe2(CH2)(2)SiMeFc(2))](2) (3) (Fc = (eta(5)-C5H4)Fe(eta(5)-C5H5)) and Fe[(eta(5)-C5H4)(SiMe2(CH2)(2)SiMe{(mu(6)-C6H5)Cr(CO)(3)}(2))](2) (6) Characterization of the synthesized molecules by H-1, C-13, and Si-29 NMR and IR spectroscopy, mass spectrometry, and elemental analysis supports their assigned structures. The electrochemical behavior has been studied. While 3 contains two pairs of outer silicon-bridged ferrocenyl units; in which the iron centers interact with one another, in the related 6 the chromium tricarbonyl groups complexed to arene rings, also joined by a single silicon, are essentially noninteracting.