A NOVEL PENTANUCLEAR CO-S RAFT CLUSTER COMPOUND CONSISTING OF FUSED CO-3(MU(3)-S) UNITS - X-RAY CRYSTAL-STRUCTURE OF CO-5(CO)(2)S-3(SC5H4N)(7)

The reaction of Na[Co(CO)(4)] with PyS-(2-mercapto-pyridine) in THF at room temperature gave a dark crystalline product [Co-5(CO)(2)(mu(3)-S )(3)(SC5H4N)(7)] (1). The crystal structure of 1 determined by single crystal X-ray diffraction, revealed a pentanuclear metallic core, Co-5 (mu(3)-S)(3)(mu-S)(4)(mu-C), which can be described as a skeleton comp rising three incomplete cubane-like structural units, two SCo3S3 and a SCo3S2C, in an inversion arrangement sharing two rhombic CoS2Co faces or, in other words, as a raft-type structure consisting of fused Co-3 (mu-S) units. The geometry around each Co atom is a distorted octahedr on and the octahedra are divided into four types according to the diff erent coordination environments. The three Co-Co bond distances of 2.7 2-2.80 Angstrom indicate weak metal-metal interactions. The formal oxi dation states of the five cobalt atoms are one Co-I and four Co-III. T he formation of 1 is discussed and the cyclic voltammetry of 1 has bee n measured. Interestingly, 1 contains three inorganic mu(3)-S atoms no twithstanding the absence of inorganic S-2-source in the synthetic rea ction system, implying a process related to desulfurization of 2-merca ptopyridine in the preparative reaction. (C) 1997 Elsevier Science Ltd .