HETEROOCTANUCLEAR CLUSTER COMPLEX-FORMATION WITH PHOSPHINE PARTICIPATION - SYNTHESIS, STRUCTURE, AND MAGNETIC-PROPERTIES OF CO6RU2(MP)(10)(PBU(3)(N))(6) (H(2)MP=2-MERCAPTOPHENOL, PBU(3)(N)=TRI-N-BUTYLPHOSPHINE)

The reaction of CoCl2, RuCl3, Na-2(mp), and PBu(3)(n) (H(2)mp = 2-merc aptophenol, PBu(3)(n) = tri-n-butylphosphine) in ethanol in the molar ratio of 0.75:0.25:1:1 gave the complex Co6Ru2(mp)(10)(PBu(3)(n))(6). The heterooctanuclear complex consists of six cobalt and two ruthenium ions chelated to as well as bridged, by the 2-mercaptophenol ligands in a near-dimeric fashion with two mu(2)-OR groups bridging the two Co 3Ru(mp)(5)(PBu(3)(n))(3) fragments without a crystallographic center o f symmetry. Each fragment is formed by binding two of the Co(mp)(2)(PB u(3)(n)) structural units and one Co(mp) species to a central Ru(III) ion through the S donors of the five mp ligands, while the sixth coord ination site of the octahedral Ru environment is completed by a phosph ine ligand in the axial position. The Co6Ru2 moiety exhibits a zigzag assembly constructed by the mu(2)-O and mu(2)-S bridges of the bidenta te 2-mercaptophenol ligands in a highly asymmetric fashion. The Co ato ms are square pyramidally coordinated with apices that are occupied by the phosphine ligands or an oxygen atom from a mp(2-) ligand. Variabl e-temperature magnetic susceptibilities that were measured in the temp erature range 300-1.6 K reveal that the spin cluster exhibits weak ant iferromagnetic exchange interactions. A quantitative interpretation of the magnetic data was carried out by the irreducible tensor operator approach. Crystal data of the complex are as follows: triclinic space group <P(1)over bar>, a = 14.931(3) Angstrom, b = 23.195(5) Angstrom, c = 24.259(5) Angstrom, alpha = 74.91(3)degrees, beta = 74.83(3)degree s, gamma = 78.80(3)degrees, and Z = 2.