Hexaaquazinc(II) dipicrate trihydrate

Acta Crystallogr C. 2007 Sep;63(Pt 9):m423-6. doi: 10.1107/S0108270107035111. Epub 2007 Aug 24.

Abstract

In the crystal structure of the title compound, [Zn(H2O)6](C(6)H(2)N(3)O(7))2.3H2O, the zinc cation complexes and picrate anions are stacked separately, extending along the b axis. No picrate species ligate to the metal cation. This lack of picrate coordination is atypical among metal picrate salts. We speculate that the size of the metal-aqua complex as related to the intermolecular distance of the picrate anions in the pi stack can be a measure of the formation of such separated stacks in the crystal structures of divalent metal complexes with picrate anions. Picrate ions are linked to each other with short intermolecular C...C contacts of 3.223 (6) and 3.194 (6) A in the stack.