Syntheses, characterization and X-ray crystal structures of hexa-coordinated monomeric and oxo-bridged dimeric Fe(III) compounds with salen-type Schiff bases

Abstract

Five Fe(III) compounds, [Fe(salophen)(N3)(MeOH)] (1) [Fe(salophen)(NCS)(MeOH)] (2), [Fe(vanophen)(HIm)2]ClO4 (3), [(μ-O){Fe(vanophen)}2]·2H2O (4) and [(μ-O){Fe(naphophen)}2]·2CH2Cl2 (5) where, H2salophen=N,N′-bis(salicylidene)phenylediamine, H2vanophen=N,N′-(1,2-phenylene)-bis(3-methoxysalicylideneimine) and H2naphophen=N,N′-bis(2-hydroxy-1-naphthaldehyde)-1,2-phenylenediimine, have been prepared and characterized by elemental analysis, IR and UV–Vis spectroscopy and single-crystal X-ray diffraction studies. In compounds 1, 2 and 3, Fe(III) has six-coordinated pseudo-octahedral geometry in which the O(1), O(2), N(1) and N(2) atoms of the deprotonated di-Schiff base constitute the equatorial plane. Both in compounds 1 and 2, methanol molecules are present in the fifth coordination sites in apical positions. The sixth coordination sites are occupied by one N atom of an azide in compound 1 and an N atom of thiocyanate in compound 2. In compound 3, both axial positions are occupied by nitrogen atoms from two different imidazole molecules. In both compounds 4 and 5, Fe(III) has a five-coordinated square pyramidal geometry with bridging oxygen atoms in the axial positions.