Lewis-base Adducts of Lead（II） Compounds：Synthesis, Structure and Quantum Chemistry Calculation of Mononuclear Pb（phen）（SCN）2

The lead thiocyanate adduct Pb(phen)(SCN)2 (phen = 1,10-phenanthroline) has been prepared by a direct synthetic method and structurally characterized. It presents a mononuclear structure and crystallizes in monoclinic, space group C2/c with a = 17.505(4), b = 13.383(3), c = 6.7916(14) (A), β = 112.25(3)o, V = 1472.6(6) (A)3, Z = 4, Dc = 2.271 g/cm3, μ(MoKα) = 11.737 mm-1, F(000) = 936, C14H8N4PbS2, Mr = 503.58, the final R = 0.0446 and wR = 0.1034 for 1601 observed reflections with I > 2σ(I). Structure analysis showed that the lead atom presents an unusual four- coordination geometry with a large vacancy, possibly indicating the stereochemical activity of 6s2 lone pair electrons.