SYNTHESES AND ELECTROCHEMISTRY OF BIMETALLIC COMPLEXES CONTAINING CYCLOHEXANEDIOLATE OR CYCLOPENTANEDIOLATE BRIDGES

The bimetallic complexes [{ML(NO)Cl}(2) (1,x-O2CnH2n-2)] [L = HB(3,5-M e(2)C(3)HN(2))(3); n = 6, x = 2-4, M = Mo; n = 5, x = 3, M = Mo or W], in which parts of cyclohexyl or cyclopentyl groups link two redox-act ive {O-ML(NO)} moieties, have been synthesized and found to exhibit tw o one-electron reduction processes separated by a potential difference , Delta E(f), which increases with decreasing through-bond metal-metal separation. The value Delta E, for [{MoL(NO)Cl}(2)(1,3-O2C6H10)] is o nly slightly less (67 mV) than that of its aryl-bridged counterpart, [ {MoL(NO)Cl}(2)(1,3-O2C6H4)]. However, Delta E(f) for [{MoL(NO)Cl}(2)(1 ,4-O2C6H10)] is ca. 300 mV smaller than for [{MoL(NO)Cl}(2)(1,4-O2C6H4 )] which contains a mesomeric link between the metal centres.