Triclinic modification of diaqua-bis-(5-carb-oxy-1H-imidazole-4-carboxyl-ato-κ(2)N(3),O(4))iron(II)

Acta Crystallogr Sect E Struct Rep Online. 2012 Aug 1;68(Pt 8):m1093-4. doi: 10.1107/S1600536812031753. Epub 2012 Jul 21.

Abstract

The title compound, [Fe(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)], is a triclinic modification of a monoclinic form recently reported by Du et al. [Acta Cryst. (2011) ▶, E67, m997]. The Fe(II) ion lies at an inversion center and is coordinated by two N and two O atoms from two 5-carb-oxy-1H-imidazole-4-carboxyl-ate ligands in trans positions, together with two water mol-ecules, completing a slightly distorted octahedral coordination. Inter-molecular N-H⋯O hydrogen bonding between the N-H group of the imidazole ring and the deprotonated carboxyl-ate group builds a chain of 5-carb-oxy-1H-imidazole-4-carboxyl-ate anions along the [101] direction. The water molecules form intermolecular hydrogen bonds to O-C and O=C sites of the carboxylate group in adjacent layers.