Synthesis, characterization, and catalytic application of a zinc(II) complex bearing a pyrazole-based ligand

The reaction between ZnCl(2) and N,N-bis[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]-1-phenylethylamine (bdmppea) affords [bdmppea)ZnCl(2)], whose structure has been determined by X-ray crystallography. The [(bdmppea)ZnEt(2)] complex in situ prepared by the reaction between (bdmppeal and ZnEt(2) exhibited high activity toward the polymerization reaction of rac-lactide at room temperature. However, its activity decreased sharply with decreasing temperature. Stereospecificity of this catalyst characterized by heterotacticity (P(r)) was determined by homonuclear decoupled NMR spectroscopy, which value was similar to 0.58. (C) 2010 Elsevier Ltd. All rights reserved.