Crystal structure of the tris 1,2-dimethyl-3-hydroxy-4-pyridinone (DMHP) complex with the Fe(III) ion

Abstract

Bidentate 1,2-dimethyl-3-hydroxy-4-pyridinone (DMHP) and its Fe(III) complex have been determined by single crystal X-ray diffraction at low temperature. Free DMHP is orthorhombic, space group Pbca, Z = 8, a = 7.253(2), b = 12.989(3), c = 13.736(4) Å, V= 1293.5(11) Å 3. Hydrogen -bonding between the hydroxyl and carbonyl oxygen donor stabilizes DMHP in dimeric units. For the Fe(III) chelate, Fe(III) ion is six-coordinate with a distorted octahedral configuration consisting of six bidentate oxygen donor atoms in FeL 3 dodecahydrate; each of the coordinated oxygen atoms of the ligand is bridged by a water molecule to adjacent donors. Chains of water molecules bridge between the Fe(III) complex and hexagonal cylinders of water. The FeL 3 chelate is trigonal, space group P3, Z = 2, a = 16.614(5), b = 16.614(5), c = 6.831(3) Å, V = 1632.9(10) Å 3. The structures were solved by direct methods and refined by least-squares techniques to R = 5.42% (1367 reflections collected) for the free ligand; and R = 5.59% (3999 independent reflections) for the Fe(III) complex.