Crystal structure of octakis(4-methoxypyridinium) bis(4-methoxypyridine-κN)tetrakis(thiocyanato-κN)ferrate(III) bis[(4-methoxypyridine-κN)pentakis(thiocyanato-κN)ferrate(III)] hexakis(thiocyanato-κN)ferrate(III) with iron in three different octahedral coordination environments

Abstract

The crystal structure of the title salt, (C6H8NO)8[Fe(NCS)4(C6H7NO)2][Fe(NCS)5(C6H7NO)]2[Fe(NCS)6], comprises three negatively charged octahedral FeIIIcomplexes with different coordination environments in which the FeIIIatoms are coordinated by a different number of thiocyanate anions and 4-methoxypyridine ligands. Charge balance is achieved by 4-methoxypyridinium cations. The asymmetric unit consists of three FeIIIcations, one of which is located on a centre of inversion, one on a twofold rotation axis and one in a general position, and ten thiocyanate anions, two 4-methoxypyridine ligands and 4-methoxypyridinium cations (one of which is disordered over two sets of sites). Beside to Coulombic interactions between organic cations and the ferrate(III) anions, weak N—H...S hydrogen-bonding interactions involving the pyridinium N—H groups of the cations and the thiocyanate S atoms of the complex anions are mainly responsible for the cohesion of the crystal structure.