Synthesis and crystal structures of ion-pairs based on anionic iron-dithiolenes and alkylammonium as countercation

Abstract

Reactions between [Fe2(CO)6(μ-SC6H2X2S)] (X = Cl or H) or FeCl3·6H2O with HSC6H2X2SH and either ONMe3 or NaOH/Et4NBr give rise to a series of iron dithiolene ion-pairs of formula (RN)2[Fe2(SC6H2X2S)4] [X = Cl or H; R=(CH3)3H or (CH3CH2)4], or {(CH3CH2)4N}2[Fe(SC6H2Cl2S)3]. The crystal structures of these iron dithiolates show very intricate crystal structure involving electrostatic interactions and a variety of complex H-bonds, Cl⋯Cl and aromatic interactions. The use of tetraethylammonium (4-5) instead of trimethylammonium (1-3) counterions imply less strong supramolecular interactions and compounds more prone to polymorphism as it is the case of 5a and 5b