Linear and Bent M(μ-CN)Pt(μ-CN)M Chains: Probes for Remote Metal−Metal Interactions

Cyanide-bridged trinuclear complexes containing square-planar platinum at the center were synthesized and
identified by structure determinations. Their chemical building blocks were cis- and trans-PtL2X2, Cp(dppe)FeX,
Cp(PPh3)2RuX (with X = Hal or CN), Pt(CN)42-, and Fe(CN)63-. Several of the intermediate dinuclear complexes
were isolated and used for reference purposes. The molecular structures, the ν(CN) IR data, the cyclic
voltammograms, and the UV−vis−near-IR spectra were used to probe the effects of the geometry at platinum
(cis vs trans), of cyanide−isocyanide isomerism (Pt(CN)2 vs Pt(NC)2), of the nature and ligation of the terminal
metals (Fe vs Ru), and of one- or two-electron oxidation. The redox properties and the observed intervalence
transfers indicate that there is electronic communication between the outer metal atoms along the linear M−CN
chains containing trans-configured platinum, but not along the bent chains containing cis-configured platinum.