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 -PtL 2 X 2, Cp(dppe)FeX, Cp(PPh 3 ) 2 RuX (with X = Hal or CN), Pt(CN) 4 2 -, and Fe(CN) 6 3 - . 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.