A hemidirected 1-D coordination polymer [Pb2(H2O)2(HBTC)2] • 3H2O extended in holodirected 3-D by weak Pb-O interactions

A new complex, [Pb-2(H2O)(2)(HBTC)(2)]center dot 3H(2)O (H3BTC = 1,3,5-Benzenetricarboxylic acid) (1), has been synthesized under hydrothermal condition. The single-crystal analysis shows that 1 consists of 1-D double-chains with Pb(II) six-coordinated by three H3BTC and one H2O molecule with the Pb-O bond distances in the range of 2.56-2.76 angstrom. When the Pb-O bonding limit extends from 2.76 to 2.90 angstrom, the potential weak bonds of Pb-0 can be found and the coordination number of Pb will increase from six to nine. As a result, the coordination geometry of Pb(II) transforms from hemidirected to holodirected and an infinite 3-D framework is obtained by the connection of the double-chains. The IR spectrum and the TGA-DTA curve of 1 are also reported in this paper. (C) 2007 Elsevier B.V. All rights reserved.