Cyanide-Bridged Arrays of 2, 3 and 4 Metal Atoms Based on Salene–Iron Complexes – Syntheses, Structures and Metal–Metal Interactions

Salene–FeIII complexes of the types LFeCl and [LFe(CN)2]− were treated with organometallic reagents to introduce the cyanide-linked units (CO)5Cr, (CO)5Mo, (CO)5W, Cp(CO)2Fe, Cp(dppe)Fe, and Cp(PPh3)2Ru. IR spectra and structure determinations revealed that all resulting complexes contained M–CN units with N coordination to the salene–Fe units. They were either dinuclear M–CN–Fe(salene), trinuclear M–CN–Fe(salene)–NC–M, or tetranuclear M–CN–Fe(salene)–Fe(salene)–NC–M species. Cyclic voltammetry showed that there are significant electronic interactions between the two outer organometallic units in the trinuclear complexes. UV/Vis spectra indicated a metal–metal charge transfer from the outer Cp(dppe)Fe groups to the central FeIII. The magnetic moments at room temperature of the tri- and tetranuclear complexes are slightly lower than those calculated for isolated high-spin FeIII species.