Communication between Co2(CO)4dppm units via polyferrocenylalkyne linkages

The synthesis and characterization of a family of ethynylbi- and ethynylterferrocenyls, I-Fc(2)C=CR, Fc(2)C=CR, and Fc(2)(C=CR)(2) (R = Fc, SiMe3), I-Fc(3)C=CSiMe3, Fc(3)C=CSiMe3, Fc(3)(C=CSiMe3)(2), and their Co-2(CO)(6) and Co-2(CO)(4)dppm complexes are described. The structure adopted by Fc(2){[Co-2(CO)(4)dppm C2SiMe3]}(2) minimizes the steric interactions between the biferrocene and dppm moieties. Electrochemical studies show that identical redox centers-ferrocenyl termini, Co-2(CO)(4)dppm units, or ferrocenyl groups in the core-communicate independently with each other.