REACTIVITY OF COPPER(II) HYDROXIDES AND COPPER(IP) ALKOXIDES FOR CLEAVING AN ACTIVATED PHOSPHATE DIESTER

Two new copper(II) chloride complexes of N-(2-hydroxyethyl)bis(pyridyl methyl)amine (CuL(2)) and N-(3-hydroxypropyl)bis(pyridylmethyl)amine ( CuL(3)) have been synthesized and characterized. The reactivities of C uL(2) and CuL(3) for cleaving bis(2,4-dinitrophenyl) phosphate (BDNPP) have been compared to that of copper(II) chloride complex of bis(pyri dylmethyl)amine (CuL(1)). The copper complex with the hydroxypropyl gr oup (CuL(3)) cleaves the phosphate diester by transesterification whil e the complex with the hydroxyethyl group (CuL(2)) or the complex with out any pendant alcohol groups (CuL(1)) cleaves it by hydrolysis. Furt hermore, CuL(3) (k = 7.2 x 10(-1) M(-1) s(-1) at 25 degrees C, pH 8.8) is about two orders of magnitude more reactive than CuL(2) (k = 9.5 x 10(-3) M(-1) s(-1)) and CuL(1) (k = 2.0 x 10(-2) M(-1) s(-1)) for cle aving the diester. The differences in the mechanisms and the reactivit ies are explained in terms of the differences in the structures of the three copper complexes. Crystal structures of [(L(1)')-Cu(OP(O)(OCH3) (2))(HOCH3)]Cl and [(L(2)')Cu(Cl)]Cl have been determined as structura l models of CuL(1) and CuL(2), respectively (L(1)' = bis(2-benzimidazo lylmethyl)amine; L(2)' = (2-hydroxyethyl)bis(2-benzimidazolylmethyl)am ine).