Effects of Big Planar Anions on the Spin Transition of a Mononuclear Manganese(III) Complex with a Hexadentate Schiff‐Base Ligand

Abstract

AbstractTwo new ion‐pair complexes [Mn(3‐MeO‐sal‐N‐1,5,8,12)][Ni(dmit)2] (1) and [Mn(3‐MeO‐sal‐N‐1,5,8,12)][Pt(mnt)2]·2CH3CN (2), based on the known six‐coordinate mononuclear Schiff‐base manganese(III) spin‐crossover complex [Mn(3‐MeO‐sal‐N‐1,5,8,12)]NO3, have been synthesized and structurally characterized. Their crystal structures indicate that increasing the size of the anion from NO3– to [Pt(mnt)2]– and [Ni(dmit)2]– leads to the dimerization of the cations and formation of alternating cation–anion stacks with loss of the most effective cation–anion interactions; only weak short contacts exist between the cations and anions. Magnetic measurements and variable‐temperature single‐crystal X‐ray crystallography analysis provided firm evidence for spin‐crossover (SCO) effects in 1. The magnetic susceptibility of compound 2 is typical of a simple paramagnet, and the manganese(III) complex cations remain in the high‐spin state in the temperature range 2–300 K.