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

Supporting information: this article has supporting information at journals.iucr.org/eCrystal structure of octakis(4-methoxypyridinium) bis(4-methoxypyridine-jN)tetrakis(thiocyanatojN)ferrate(III) bis[(4-methoxypyridine-jN)-pentakis(thiocyanato-jN)ferrate(III)] hexakis(thiocyanato-jN)ferrate(III) with iron in three different octahedral coordination environments Aleksej Jochim,* Inke Jess and Christian Näther Institut fü r Anorganische Chemie, Christian-Albrechts-Universität Kiel, Max-Eyth Strasse 2, D-24118 Kiel, Germany. *Correspondence e-mail: ajochim@ac.uni-kiel. de The crystal structure of the title salt, (C 6 H 8 NO) 8 [Fe(NCS) 4 [Fe(NCS) 6 ], comprises three negatively charged octahedral Fe III complexes with different coordination environments in which the Fe III atoms 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 Fe III cations, 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-HÁ Á ÁS 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. Chemical contextRecently, the synthesis of new coordination compounds based on paramagnetic metal cations has become increasingly interesting. In particular, compounds in which the paramagnetic metal cations are linked by small-sized anionic ligands that can mediate magnetic exchange are of special importance. For example, this can be achieved by thio-or selenocyanate anions that are able to coordinate to a central metal cation in different ways (Palion-Gazda et al., 2015;Guillet et al., 2016;Prananto et al., 2017). Most of the reported compounds contain terminally N-bonded thiocyanate ligands, whereas compounds with these ligands in a bridging mode are relatively rare. Nevertheless, the latter can be obtained by thermal decomposition of precursor complexes with terminal anionic ligands, as we have recently shown. With monodentate co-ligands, such as simple pyridine derivatives substituted in the 4-position, we were able to synthesize a number of compounds (predominantly including divalent cobalt or nickel), in which the metal cations are linked by pairs of anionic ligands into chains (Rams et al., 2017a,b;Wö hlert et al., 2012;Werner et al., 2015). In this context, divalent iron compounds are also of interest, but are scarce in comparison to divalent cobalt or nickel compounds because they are more difficult to synthesize in solution due to the poor oxidation Structural commentaryThe asymmetric unit of the title compound comprises three iron(III) cations, of which one is located on ...