Synthesis, Structure, and Magnetic Properties of New Spin Crossover Fe(II) Complexes Forming Short Hydrogen Bonds with Substituted Dicarboxylic Acids

We synthesized new Fe(II) compounds consisting of [Fe(L)2] (HL: 2-Acetylpyridine isonicotinoylhydrazone) and dicarboxylic acids. Single crystal analysis shows that short hydrogen bonds are formed between [Fe(L)2] and dicarboxylic acids. The hydrogen bonding interactions between metal complexes and dicarboxylic acids are complemented by π-π interactions, forming two-dimensional network structures. Magnetic properties show that the Fe(II) compounds exhibit gradual spin crossover behavior around room temperature and a T1/2 value is dependent on the halogen substituent on the dicarboxylic acids