Phosphoraneiminato acetate cluster of copper and zinc.: Crystal structures of [Cu4(NPEt3)2(O2CCH3)6] and [Zn4(NPEt3)2(O2CCH3)6]

The anhydrous acetates of copper(II) and zinc react with the silylated phosphaneimine Me3SiNPEt3 in dichloromethane at 20 degrees C forming the mixed phosphoraneiminato acetate clusters [Cu-4(NPEt3)(2)(O2CCH3)(6)] (I), which forms emerald crystals, and colourless [Zn-4(NPEt3)(2).(O2CCH3)(6)] (2). In spite of analogous composition the structures of 1 and 2 are completely different. In the asymmetric unit of I three copper atoms of an almost isosceles triangle are linked via two nitrogen atoms of the NPEt3- groups to form a trigonal bipyramidal aggregate. One of these three copper atoms is chelated by an acetate group, another one is connected with the fourth copper atom via three mu(2)-O2C-CH3 groups. The asymmetric units are associated via a mu(2)-O2C-CH3 group and a mu(3)-OC(O)CH3 group at a time so that infinite chains result. In 2 two zinc atoms are linked via the nitrogen atoms of the two NPEt3- groups to form an almost centrosymmetric four-membered ring. Both nitrogen atoms of the four-membered ring are connected with another zinc atom each. These zinc atoms again are linked with the zinc atoms of the Zn2N2 four-membered ring via two mu(2)-O2C-CH3 groups each and additionally coordinated with a terminal acetate ligand each.