Solvation of iron(II) complexes of hexadentate tris-diimine Schiff base tripod ligands in alcohol–water and DMSO–water mixtures

Solubilities of the perchlorate salt of the iron(II) complex of the tripodal ligand derived from tris(2-aminoethyl)amine and pyridine 2-carboxaldehyde, [Fe({pyH}3tren)](ClO4)2, have been determined in MeOH-, i-PrOH-, t-BuOH-, and DMSO–H2O mixtures. Solubilities of [Fe({pyMe}3tren)](ClO4)2 and of [Fe({pyPh}3tren)](ClO4)2, analogues derived from 2-acetylpyridine and 2-benzoylpyridine, respectively, have been determined in MeOH–H2O mixtures. Transfer chemical potentials for the three complexes have been calculated from these solubilities, and solvation trends for these complexes discussed in relation to the overall pattern for iron(II)-diimine complexes in binary aqueous solvent mixtures. The crystal structure of [Fe({pyH}3 tren)](ClO4)2 has been determined.