COORDINATION CHEMISTRY OF ORGANOMETALLIC POLYDENTATE LIGANDS - STUDIES ON THE SYNTHESES AND PROPERTIES OF FE-M BINUCLEAR COMPLEXES PREPAREDFROM ORGANOMETALLIC TRIDENTATE LIGAND TRANS-FE(CO)(3)(PH(2)PPY)(2) (PH(2)PPY=2-(DIPHENYLPHOSPHINO)PYRIDINE)

The binuclear complexes (CO)(3)Fe(mu-Ph(2)Ppy)(2)MX(n) (Ph(2)Ppy = 2-( diphenylphosphino)pyridine, MX(n) = Mn(SCN)(2), Co(SCN)(2), CoCl2, NiC l2, Mo(CO)(3), Zn(SCN)(2), ZnCl2, Cd(SCN)(2), CdCl2, HgCl2, HgI2, AgCl O4, and SnCl2) were prepared from the new type of organometallic tride ntate ligand, trans-Fe(CO)(3)(Ph(2)Ppy)(2) (1), which contains both a basic metal center and bridging phosphine ligands. The crystal structu re of the benzene solvate of 1 was determined by X-ray diffraction. Th e compound 1 . 1/2C(6)H(6) crystallizes in the monoclinic space group P2(1)/c with a = 17.560(5), b = 12.110(1), c = 18.176(4) Angstrom; bet a = 101.27(2)degrees and Z = 4. The structure was refined to a convent ional R value of 0.077 by using 2670 significant reflections and param eters, The structure of one of the binuclear complexes, namely, (CO)(3 )Fe(mu-Ph(2)Ppy)(2)HgI2 (14), has also been determined by X-ray diffra ction. The compound 14 crystallizes in the monoclinic space group P2(1 )/n, with a = 13.829(2), b = 14.175(2), c = 19.514(3) Angstrom, beta = 120.27(1)degrees, V = 3738(2) Angstrom(3) and Z = 4. The structure wa s refined to a conventional R value of 0.032 by using 3279 significant reflections and parameters. The Fe-Hg distance is 2.678 Angstrom, ind icative of a metal-metal bond. Results of Mossbauer and electron-absor ption spectra suggested the presence of metal to metal interactions in these binuclear complexes.