Synthesis and structural characterization of osmium cluster complexes containing 2-phenylazopyridine. Crystal structures of [Os3(CO)10(NC5H4-N=N-C6H5)] and [Os3(CO)10(m-H)(NC5H3-N=N(O)-C6H5)]

Abstract

The reaction of [Os3(CO)lo(MeCN)2] with 2-phenylazopyridine (2-PAP) affords [Os3(CO)Io(NCsH+-N=N-C6H5)] (1), [Os3(CO) lo(/z-H) (NC5H3-N=N(O)--C6H5) ] (2) and a violet product 3, which is an isomer of 1. In 1, the 2-PAP moiety acts as the rarely observed six-electron donor. Cluster 2 contains an 'oxidized' 2-PAP moiety bonding in the usual ortho-metallated mode of pyridine. Both clusters 1 and 2 have been fully characterized in solution by conventional spectroscopic methods and in the solid state by single crystal X-ray diffraction analysis. Crystals of 1 are orthorhombic, space group P222, Z=4, with unit cell dimensions a=9.123(1), b= 17.217(2), c = 16.168 (2)/,. Crystals of 2 are triclinic, space group P1, Z = 2, with unit cell dimensions a = 9.308 (2), b = 11.250 (2), c = 12.934( 2 ) A, a=77.23(1), fl=72.26(1), y= 85.21 (1) °.