Nitrile-Rich Coordination Polymer 1{[Fe(CH3CN)4(pyrazine)](ClO4)2} Exhibiting a HS ⇆ LS Transition

In a 1D network of 1{[Fe(CH3CN)4(pyrazine)](ClO4)2}, the presence of four neutral nitrile molecules besides the pyrazine donors in the first coordination sphere of iron(II) allows one to achieve a ligand field strength appropriate for the “spin-crossover” occurrence.