| Popis: |
The Cu II —diamine complexes, (bipy)CuSO 4 and (tmen)CuSO 4 , catalyze the hydrolysis of p -nitrophenyl diphenyl phosphate (PNDP) adsorbed on a strong-base ion exchange resin. Turnover is observed. The major hydrolysis products are diphenyl phosphate, p -nitrophenyl phenyl phosphate, and the ethanolysis product ethyl diphenyl phosphate (EDPP) which are observed in similar amounts in both the presence and absence of the Cu II —diamine catalysts. The apparent bimolecular rate constants found for the (bipy) CuSO 4 and (tmen)CuSO 4 catalysts are 0.023 and 0.024 M −1 s −1 , respectively. CuSO 4 is inactive as a catalyst. 31 P MAS NMR relaxation measurements of the stable EDPP product reveal that the Cu II —diamine complexes greatly enhance T 1 relaxation, whereas CuSO 4 has only minimal effect. These results are consistent with the complexation of neutral phosphorus esters by the Cu II —diamine catalysts. 31 P T 1 measurements of hydrolytically-stable dimethyl methylphosphonate (DMMP) in water solutions of Cu 2+ , (tmen)Cu 2+ , and Mn 2+ suggest that DMMP exchanges rapidly between inner-sphere and outer-sphere complexes in a nearly identical manner with each of these paramagnetic species. |
