Alkaline-earth metal complexes of thiol-pendant crown ethers as turnover catalysts of ester cleavage

P Breccia, R Cacciapaglia, L Mandolini…

Index: Breccia, Perla; Cacciapaglia, Roberta; Mandolini, Luigi; Scorsini, Carla Journal of the Chemical Society. Perkin Transactions 2, 1998 , # 5 p. 1257 - 1261

Full Text: HTML

Citation Number: 9

Abstract

Methanolysis of pNPOAc under moderately alkaline conditions is catalysed by the alkaline- earth metal ion (Ca, Sr, Ba) complexes of 2-(mercaptomethyl)-18-crown-6 according to biphasic kinetics in which an initial burst of pNPOH release is followed by a zeroth-order phase. Two competing catalytic mechanisms contribute to the overall process,(i) a double displacement mechanism in which the complexed metal ion enables the SH group of the ...