Inorganic Chemistry, Vol.33, No.13, 2743-2747, 1994
Pyridine Coordination-Complexes of the Divalent Ytterbium Chalcogenolates Yb(EPH)2 (E=s, Se, Te)
Chalcogenolate complexes of ytterbium can be prepared via a number of synthetic approaches. The reaction between Yb metal and PhE-EPh (E = S,Se,Te) in liquid ammonia results in the formation of divalent ytterbium chalcogenolates, which can be isolated as the pyridine coordination complexes (pyridine)4Yb(SC6H5)2 (1) (pyridine)4Yb(SeC6H5)2 (2), and (pyridine)5Yb(TeC6H5)2 (3). Reaction of YbCl3 with 3 equiv of NaTePh results in the reduction of the metal and the formation of 3 and diphenyl ditelluride. The thiolate 1 and selenolate 2 can be prepared by reducing the corresponding dichalcogenide with a ytterbium/mercury amalgam in THF. All three ytterbium complexes have been characterized by elemental analysis and by NMR, IR, and UV-visible spectroscopy. The visible spectra were found to be concentration dependent. All three complexes have also been characterized by single-crystal X-ray diffraction and shown to be molecular, with trans phenylchacogenolate ligands. Octahedral 1 crystallizes in the triclinic space group P1BAR, with a = 8.797(3) angstrom, b = 9.412(4) angstrom, c = 9.947(7) angstrom, alpha = 87.07(4)degrees, beta = 66.79(4)degrees, gamma = 75.25(3)degrees, V = 730.9(7) angstrom3, Z = 1, and rho(calc) = 1.608 g/cm3 (Mo Kalpha radiation at -115-degrees-C). Octahedral 2 crystallizes in the space group C2/c, with a = 25.670angstrom(6) angstrom, b = 9.027(4) angstrom, c = 17.680(3) angstrom, beta = 133.62(2)degrees, V = 2966(2) angstrom3, Z = 4, rho(calc) = 1.795 g/cm3 (Mo Kalpha radiation at -120-degrees-C). The pentagonal bipyramid 3 crystallizes in the space group Pbca, with a = 13.695(9) angstrom, b = 16.422(8) angstrom, c = 31.917(7) angstrom, V = 7178(6) angstrom3, Z = 8, rho(calc) = 1.83 g/cm3 (Mo Kalpha radiation at -120-degrees-C). The metal-chalcogenide bond lengths in all three structures can be predicted with the summation of ionic radii.
Keywords:THERMAL-DECOMPOSITION;CRYSTAL-STRUCTURE;THIN-FILMS;SEMICONDUCTORS;BULK;CHALCOGENIDES;PRECURSORS;CD(SPH)2;DEVICES;ZNS