Synthesis, structure, and spin equilibrium properties of [Fe III X 2 L]BPh 4 ⋅solvents (X = 1-methylimidazole and imidazole; L = N , N ′-bis(3-ethoxycarbonylsalicylidene)ethylenediamine)
imidazoles. Complex 1 is described as isolated molecule, while complex 2 has a hydrogen-bonded cyclic dimer structure constructed by hydrogen-bond between imidazole group and ethoxycarbonyl oxygen via ethanol. Complex 1 is in a high-spin (S = 5/2) state over the whole temperature region 5–300 K, while complex 2 showed a gradual complete spinequilibriumbetween high and low-spin states at T1/2 = 192 K.