Lattice effects on the spin-crossover profile of a mononuclear manganese(III) cation

Six solvated salts of a mononuclear manganese(III) complex with a chelating hexadentate Schiff base ligand are reported. One member of the series, MnL]PF(6)?0.5?CH(3)OH (1), shows a rare low-spin (LS) electronic configuration between 10-300?K. The remaining five salts, MnL]NO(3)?C(2)H(5)OH(2), MnL]BF(4)?C(2)H(5)OH(3), MnL]CF(3)SO(3)?C(2)H(5)OH (4), MnL]ClO(4)?C(2)H(5)OH (5) and MnL]ClO(4)?0.5?CH(3)CN (6), all show gradual incomplete spin-crossover (SCO) behaviour. The structures of all were determined at 100?K, and also at 293?K in the case of 3-6. The LS salt MnL]PF(6)?0.5?CH(3)OH is the only member of the series that does not exhibit strong hydrogen bonding. At 100?K two of the four SCO complexes (2 and 4) assemble into 1D hydrogen-bonded chains, which weaken or rupture on warming. The remaining SCO complexes 3, 5 and 6 do not form 1D hydrogen-bonded chains, but instead exhibit discrete hydrogen bonding between cation/counterion, cation/solvent or counterion/solvent and show no significant change on warming.