Crystal structures and catalytic activities of Zn(II) compounds containing 1,3-bis(4-pyridyl)propane

The structures of new compounds containing Zn(II) ions and bpp (1,3-bis(4-pyridyl)propane) ligands have been determined. The coordinating halides (Br- or Cl-) produce one-dimensional compounds 6 and 7, and intra- and inter-chain C-H center dot center dot center dot X (X = Br or 1) interactions play roles for building crystal structures with the flexible bpp ligands. The non-coordinating PF6- anions do not produce hydroxyl bridged zinc cations or polymeric compounds, and produce only a monomeric complex 4 containing four bpp ligands and two water ligands. Previously reported polymeric compounds 1 and 2 containing hydroxyl-bridged zinc cations [Zn2OH] were found to carry out the catalytic transesterification of a range of esters with methanol at room temperature under the mild conditions, whereas the rest of compounds did not catalyze the transesterification reactions at all. In addition, the catalysts 1 and 2 have shown even better catalytic activity than zinc salts Zn(NO3)(2) and Zn(OTf)(2). (c) 2006 Elsevier B.V. All rights reserved.