Redox properties of two new ruthenium(III) isocyanide complexes, trans-[NBu4][RuX4(CNTM)(2)](X = Cl or Br, CNTM = p-tolylsulfonylmethylisocyanide)

New ruthenium(III) complexes trans-[NBu4][RuX4(CNTM)(2)] (X = Cl or Br, CNT M = p-tolylsulfonylmethylisocyanide) have been prepared by treating [NBu4]( 2)[RuX6] with the isocyanide ligand CNTM in EtOH-CH2Cl2 solution. In situ I R and UV-Vis spectroelectrochemical studies have shown that reduction of tr ans-[RuX4(CNTM)(2)](-) in acetonitrile and subsequent oxidation yields mer, trans-[RuX3(CNTM)(2)(NCMe)]. Similar studies have shown, interestingly, tha t oxidation of trans-[RuX4(CNTM)(2)](-) and subsequent reduction also yield s the same product. Differences between the redox behaviour of trans-[RuX4( CNTM)(2)](-) and trans-[RuX4((CNBu)-Bu-t)(2)](-) (X = Cl or Br, (CNBu)-Bu-t = tert-butylisocyanide) in the presence of free isocyanide ligand have als o been identified. (C) 2000 Elsevier Science S.A. All rights reserved.