Bismuth–ferrocene carboxylates: synthesis and structure

Abstract

The reaction of ferrocenedicarboxylic acid with triphenylbismuth in a 1 : 1 ratio under solvothermal conditions afforded the 1D coordination polymer [Bi₂(μ₂-η²-OOCFcCOO-μ₂-η²)(η²-OOCFcCOO-η²)(μ₂-η²-OOCFcCOO-η²)]_n (1). In this polymer two types of bismuth centers (hepta- and octacoordinate) are present and are interconnected by the bridging coordination of ferrocene dicarboxylate ligands. The reaction of ferrocenecarboxylic acid with triphenylbismuth in a 1 : 3 ratio, in toluene, under refluxing conditions, afforded the 1D coordination polymer [Bi(μ₂-η²-FcCOO)(η²-FcCOO)₂]_n (2). In the solid state, 2 exists as a helical polymer, where the inner bismuth chain is enclosed by an external sheath of ferrocene carboxylate ligands. In solution, however, 2 decomposes into the monomeric repeat unit [Bi(FcCOO)₃] which is indicated by ESI-MS as well as cyclic voltammetric studies. Thus, a single, quasi-reversible redox event is seen for 2 in solution. The reaction of triphenylbismuth with ferrocenecarboxylic acid in a 1 : 1 stoichiometry afforded the molecular dimer [Bi₂(μ₂-η²-FcCOO)₂(η²-FcCOO)₄(H₂O)₄]·(2FcCOOH) (3). Compounds 1–3 reveal rich supramolecular architectures in the solid state as a result of the presence of C–H⋯O, C–H⋯π and π⋯π interactions.