Solvatomorphism and Anion Effects in Fluorinated Mn III Spin Crossover Complexes

Eight new Mn III salts of the [Mn III (3,5‐diF‐sal 2 323)]X complex are reported, of which four show thermal spin crossover (SCO): 1a [Mn III (3,5‐diF‐sal 2 323)]PF 6 ·0.33CH 3 CN, 1b [Mn III (3,5‐diF‐sal 2 323)]PF 6 ·CH 3 CN, 1c [Mn III (3,5‐diF‐sal 2 323)]PF 6 , 2 [Mn III (3,5‐diF‐sal 2 323)]AsF 6 , 3 [Mn III (3,5‐diF‐sal 2 323)]NO 3 , 4 [Mn III (3,5‐diF‐sal 2 323)]Br, 5 [Mn III (3,5‐diF‐sal 2 323)]BF 4 , and 6 [Mn III (3,5‐diF‐sal 2 323)]OTf·0.66H 2 O. Solvatomorphism is observed in the PF 6 − salt, revealing one complex which undergoes gradual SCO ( 1a ·0.33CH 3 CN), one that is fully high spin ( 1b ·CH 3 CN); a third solvent‐free solvatomorph 1c is also recovered where structural data indicate a spin triplet at 100 K. In 1a , three independent Mn III sites with spin state ordering of HS:LS:LS at 100 K and HS:IS:IS at 293 K are observed, where HS = high spin ( S  = 2), LS = low spin ( S  = 1), and IS = intermediate spin (i.e., an equilibrium of S  = 1 and S  = 2). Structural data are presented for all complexes, and magnetic data for 1a , 1b , 2 , and 3 .