Center for Functional Nanomaterials Seminar

Several ruthenium compounds and a new material have been developed with the goal of using them for molecular wires. Two different strategies have been employed: Olefin Metathesis for Metal Incorporation (OMMI) and ligand exchange. In this work, OMMI was used towards the preparation of compounds of the form L2Cl2Ru=CH(CH=CH)nCH=RuL2Cl2 (n = 0, 1, and >20). Complexes with n > 20 have been prepared by treating polyacetylene (PA) with the olefin metathesis catalyst (H2IMes)RuCl2(=CHPh)(3-bromopyridine)2 (G2B) to form “metal-incorporated polyacetylene” (MIPA). Many properties of the MIPAs mimicked those of the untreated polyacetylene, including iodine-doped conductivity. Progress towards the synthesis of complexes with n = 0 or 1 has been accomplished using the combination of two previously known strategies for metathesis reactions, namely Olefin Metathesis for Metal Incorporation (OMMI) and Relay Ring-Closing Metathesis (RRCM). Relay Olefin Metathesis for Metal Incorporation (ROMMI) has been used as a proof of principle to prepare a known conjugated diruthenium bisalkylidene complex, [(Cy3P)2Cl2Ru]2(μ-CHCH=CHCH). This method was applied towards the preparation of compounds previously inaccessible by direct OMMI on the CH2 terminated polyene. The synthesis of several other ruthenium compounds using ligand exchange reactions began primarily with (PCy3)2RuCl2(=CHPh) (G1). One class of compounds used two bis(imidazolium) ligands, consisting of two fused imidazolium rings. Attempts have been made to attach this ligand to Ru to form metathesis active, diruthenium complexes. The addition of carbon monooxide to similar Ru complexes will also be discussed.