Preparation and characterisation of linear mixed-metal trinuclear carboxylate complexes of general formula [M2M′(O2CR)6(C9H7N)2]; crystal structure of [Zn2Ba(O2CCMe3)6(C9H7N)2]

Abstract

The complexes [Co₂M(O₂CCHCHMe)₆(C₉H₇N)₂] where M = Zn or Mn, C₉H₇N = quinoline, [Zn₂Co(O₂CPh)₆(C₉H₇N)₂], [Zn₂M(O₂CMe)₆(C₉H₇N)₂] where M = Zn or Mn, and [Zn₂Ba(O₂CCMe₃)₆(C₉H₇N)₂] have been prepared by the stoicheiometric additon of metal carboxylate salts to an ethanolic solution of quinoline. Solid-state u.v.–visible, i.r. and magnetic measurements are all consistent with the presence of linear arrays of three metal ions bonded by bridging carboxylates and terminal quinoline ligands. An X-ray crystallographic investigation of the barium complex show that all of the carboxylates are of the syn–syn bridging type across Ba ⋯ Zn separations of 4.13(1) and 4.22(1)Å.