Two-Dimensional Holo- and Hemidirected Lead(II) Coordination Polymers: Synthetic, Spectroscopic, Thermal, and Structural Studies of [Pb(μ-SCN)2(μ-ebp)1.5]n and {[Pb(μ-OAc)(μ-ebp)](ClO4)}n (ebp=4,4′-[(1E)-Ethane-1,2-diyl]bis[pyridine]; OAc=Acetato)

Abstract

Two new coordination polymers of Pb11 complexes with bridging 4,4′-[(1E)-ethane-1,2-diyl]bis[pyridine] (ebp), thiocyanato, and acetato ligands, [Pb(μ-SCN)<inf>2</inf>(μ-ebp)<inf>1.5</inf>]<inf>n</inf> (1) and {[Pb(μ-OAc)(μ-ebp)](ClO<inf>4</inf>)}<inf>n</inf> (2), were synthesized and characterized by elemental analysis, FT-IR, 1H- and 13C-NMR, thermal analysis, and single-crystal X-ray diffraction. In 1, the Pb2+ ions are doubly bridged by both the ebp and the SCN - ligands into a two-dimensional polymeric network. The seven-coordinate geometry around the Pb2+ ion in 1 is a distorted monocapped trigonal prism, in which the Pb2+ ions have a less-common holodirected geometry. In 2, the Pb2+ ions are bridged by AcO - ligands forming linear chains, which are also further bridged by the neutral ebp ligands into a two-dimensional polymeric framework. The Pb 2+ ions have a five-coordinate geometry with two N-atoms from two ebp ligands and three O-atoms of AcO-. Although ClO<inf>4</inf> acts as a counter-ion, it also makes weak interactions with the Pb2+ center. The arrangement of the ligands in 2 exhibits hemidirected geometry, and the coordination gap around the Pb2+ ion is possibly occupied by a configurationally active lone pair of electrons. © 2005 Verlag Helvetica Chimica Acta AG.