A novel crystal structure of {tris[ 4-(1H-pyrazol-3-yl-κN2)-3-azabut-3-enyl]amine-κN}iron(II) bis(tetrafluoridoborate) methanol monosolvate featuring a low-spin configuration

Mononuclear complexes are good model systems for evaluating the effects of different ligand systems on the magnetic properties of iron(II) centres. A novel crystal structure of the title compound, [Fe(C18H24N10)](BF4)(2)center dot CH3OH, with one molecule of methanol per formula unit exhibits a strictly sixfold coordination sphere associated with a low-spin configuration at the metal centre. The incorporated methanol solvent molecule promotes extended hydrogen-bonding networks between the tetrafluoridoborate anions and the cationic units. A less constrained crystal structure regarding close contacts between the tetrafluoridoborate anions and the cationic units allows a spin transition which is inhibited in the previously published hydrate of the title compound.