Crystallographic characterisation of novel Zn(II) silsesquioxane complexes and their application as initiators for the production of polylactide

Herein, the solid state structures of the products from the reaction of the silsesquioxane trio (iso-C4H9)(7)Si7O12(OH)(3) (1)with two equivalents of ZnMe2 in both THF and toluene are reported. In both cases tetrametallic Zn(II) complexes were isolated, with toluene [(iso-C4H9)(7)Si7O12](2)Zn4Me2 (2) was prepared while performing the reaction in THF the analogous complex [(iso-C4H9)(7)Si7O12](2)Zn4Me2(THF)(2) (3) was formed. Both species have also been characterised via H-1, C-13{H-1} and Si-29{H-1} NMR spectroscopy, which confirm the solid state structures are maintained in solution. Both 2 and 3 show modest activities for the polymerisation of rac-lactide and a heterogeneous catalyst has also been prepared. (C) 2009 Elsevier Ltd. All rights reserved.