Thermal properties and crystal structures of manganese(III)-salen complexes with the Tf2N anion [Tf2N = bis(trifluoromethanesulfonyl)amide)

Abstract

A series of salts comprising cationic manganese(III)-salen complexes and the Tf2N anion has been prepared (salen=N,N′-bis(salicylideneaminato)ethylene, Tf2N=bis(trifluoromethanesulfonyl)amide) to investigate the effects of axial ligands and substituents on their thermal properties. [Mn(salen)L2][Tf2N] (L=H2O, pyridine) and their 5-butoxysalen analogs undergo thermal desorption of the axial ligands, followed by decomposition above 250°C. The pyridine complexes exhibit two-step ligand desorption, corresponding to the formation of a dimer and later, desorption from the dimer. Complexes with L=3-butylpyridine and N-butylimidazole melt at 97.6 and 132.7°C, respectively, before ligand desorption. Crystal structures of these and related complexes have been determined. [Mn(salen)(3,3′-bipyridine)][Tf2N] is a coordination polymer with higher thermal stability.