Inorganic Chemistry 2004-10-18

Well-defined calcium initiators for lactide polymerization.

Malcolm H Chisholm, Judith C Gallucci, Khamphee Phomphrai

Index: Inorg. Chem. 21th ed., 43 , 6717-6725, (2004)

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Abstract

A series of monomeric amide or aryloxide complexes of the form LCaX, where L = CH[CMeNC(6)H(3)-2,6-](2), CH[CMeNC(6)H(4)-2-OMe](2), a bulky tris-pyrazolyl borate, Tp(iPr) or Tp(tBu) or 9-BBN-pz(2) and X = N(SiMe(3))(2) or OC(6)H(3)-2,6-, has been prepared and characterized and investigated in the ring-opening polymerizations of lactide. The compounds (Tp(tBu))CaX in THF are shown to be highly active and stereoselective. The propylene oxide complex (Tp(tBu))Ca(OC(6)H(3)-2,6-).(PO) has been isolated and structurally characterized (single-crystal X-ray) and shown to be inert to the polymerization of PO.