Communication between Remote Moieties in Linear Ru–Ru–Ru Trimetallic Cyanide-Bridged Complexes

In this article, we report the structural, spectroscopic, and electrochemical properties of the cyanide-bridged complex salts trans-[(NC)­RuII(L)4(μ-CN)­RuII(py)4Cl]­PF6 and trans-[RuII(L)4{(μ-CN)­RuII(py)4Cl}2]­(PF6)2 (L = pyridine or 4-methoxypyridine). The mixed-valence forms of these compounds show a variety of metal-to-metal charge-transfer bands, including one arising from charge transfer between the remote ruthenium units. The latter is more intense when L = 4-methoxypyridine and points to the role of the bridging ruthenium unit in promoting mixing between the dπ orbitals of the terminal fragments.