New insights on the electronic, magnetic, electric and molecular structure of a bis-(4-cyanopyridine) iron(III) complex with the meso-tetrakis(4-methoxyphenyl)porphyrin

Abstract We have successfully synthesized and characterized a new low-spin iron(III) bis(4-cyanopyridine) complex with a meso -porphyrin substituted in the para positions of the phenyls by the methoxy group, namely the bis(4-cyanopyridine)[( meso -tetrakis(4-metoxyphenylporphyrinato)]iron(III) trifluoromethanesulfonate chlorobenzene monosolvate complex with the formula [Fe III (TMPP)(4-CNpy) 2 ]SO 3 CF 3 .C 6 H 5 Cl ( I ). This species was characterized through ultraviolet–visible, Fourier-transform infrared and Mossbauer spectroscopy as well as by SQUID magnetometry, cyclic voltammetry, and X-ray crystallography. These characterizations indicated that our synthetic heme model is a low-spin (S = 1/2) coordination compound and especially shows that the structural, electronic and the magnetic properties of complex ( I ) are closely dominated by the presence of the methoxy σ-donor group at the para positions of the meso -porphyrin.