Syntheses, hydrogen-bonded assembly structures, and spin crossover properties of [FeIII(Him)2(n-MeOhapen)]PF6 (Him = imidazole and n-MeOhapen = N,N′-bis(n-methoxy-2-oxyacetophenylidene)ethylenediamine); n = 4, 5, 6)

Three iron(III) complexes [FeIII(Him)2(n-MeOhapen)]PF6 (1: n = 4, 2: n = 5, 3: n = 6) were synthesized, where Him = imidazole and n-MeOhapen = N,N′-bis(n-methoxy-2-oxyacetophenylidene)ethylenediamine. Two adjacent [FeIII(Him)2(4-MeOhapen)]+ cations in 1 are connected via PF6− ion by hydrogen bonds between the imidazole group and PF6− ion to give a 1D chain. Two adjacent cations in 2 are connected via hydrogen bonds between phenylidene oxygen and imidazole atoms to form a cyclic dimer structure. Two EtOH molecules are involved in a hydrogen-bonded cyclic dimer structure in 3. 1 and 2 showed a SCO behavior, but 3 showed incomplete SCO.