Counter-anions-tuned crystal structure and intermolecular interactions of a series of iron (II) complexes derived from 4,4′-dimethyl-2,2′-bipyridine.

A series of Fe(II) complexes with (ClO4)−(SeCN)−, (ClO4)−(SCN)−, (Fe2OCl6)2−, and 2(BF4)−counter-anions for complexes1–4, derived from dmbpy (4,4′-dimethyl-2,2′-bipyridine), were prepared. The single-crystal studies and the Hirshfeld surfaces analysis revealed that the (Fe2OCl6)2−anion results more distortional octahedral geometry of the cation than other anions. In particular, the (ClO4)−(SCN)−and (Fe2OCl6)2−anions lead to complexes2and3stabilized via C-H···π interactions and π···π interactions, which were not found in the other two complexes. However, the double-chain structure of complex4was formed by C-H···F and C-H···C hydrogen bonds interactions. Due to the influence of different anions, magnetic susceptibility measurements showed that complex1was in high-spin (HS) state and complex2was in low-spin (LS) state. [ABSTRACT FROM PUBLISHER]