Crystal structures and catalytic activities of Zn(II) compounds containing btp ligands

摘要

The structures of new compounds containing Zn(II) ions and btp (2,6-bis(N'-1,2,4-triazolyl)pyridine) ligands have been determined. With coordinating chloride and bromide anions, Zn(II) produces chains 2 and 3 containing C-H... X(Cl or Br) weak interactions to build crystal structures and they are face-to-face aligned. With non-coordinating ClO4- and PF6- anions, Zn(II) produces monomeric compounds 4 and 5 containing H-bonds between anions and water ligands and face-to-face pi-pi interactions to build crystal structures. The previously reported polymeric compound 1 containing [Zn(NO3)(H2O)(2)(btP)(2)](+) units bridged by btp ligands was found to carry out the catalytic transesterification of a range of esters with methanol at room temperature under mild conditions, whereas it did not catalyze the ring opening of epoxide (easier reaction) with methanol. These results indicate that the polymeric compound I shows selective reactivity. In addition, the catalyst I has shown even better catalytic activity than the corresponding Zn(NO3)(2) salt. (c) 2005 Elsevier B.V. All rights reserved.