Syntheses, stereochemistry, reactivity, and some properties of sulfur-bridged cobalt(III)–cadmium(II) polynuclear complexes derived from mononuclear cobalt(III) complex with d-penicillaminate

A reaction of the octahedral bidentate metalloligand, trans(N)-[Co(d-pen)2]− (d-pen=d-penicillaminate) with Cd(NO3)2 or Cd(ClO4)2 gave a novel S-bridged trinuclear complex, [Cd(H2O){Co(d-pen)2}2] (1). In this complex molecule, the central Cd atom is surrounded by four S atoms from two [Co(d-pen)2]− units and one O atom of a H2O molecule to form a distorted five-coordinated geometry. Each of two terminal [Co(d-pen)2]− units takes an approximately octahedral geometry and has a similar trans(N) geometry to that of the starting material. On the other hand, the reaction of trans(N)-[Co(d-pen)2]− with CdCl2 in the molar ratio of 1:1 gave an S-bridged dinuclear complex, [CdCl{Co(d-pen)2}(H2O)m]·nH2O (m+n=4) (2). The reactivity of trans(N)-[Co(d-pen)2]− toward CdCl2 is significantly influenced by the ratio of two components, and the formation of a similar trinuclear species to 1 is also suggested under the condition with excess amount of trans(N)-[Co(d-pen)2]−. Some spectrochemical properties of these complexes are also discussed in relation to their structures.