SYNTHESIS, CHARACTERIZATION AND CRYSTAL-STRUCTURES OF NOVEL HAFNIUM PORPHYRINS

Dichlorohafnium porphyrin complexes [Hf(por)Cl2] [por = 2,3,7,8,12,13,17,18-octaethylporphyrinate (oep) or 5,10,15,20-tetraphenylporphyrinate (tpp)] which are potentially useful precursors for various hafnium porphyrin complexes, were synthesised and characterized. The structure of [Hf(oep)Cl2(H2O)] has been determined by X-ray crystallography; the co-ordination geometry around the Hf atom can be described as a 4:3 piano-stool with the square base occupied by the porphyrin N atoms and the legs by the two Cl atoms and a water molecule. Treatment of [Hf(por)Cl2] with [NBun4]3[P3O9] gave [NBun4][Hf(por)(P3O9)] (por = oep and tpp). The crystal structure of the oep complex revealed a seven-co-ordinate Hf atom surrounded by 4 N atoms of the porphyrin and 3 O atoms of the P3O93- ligand. The N4 and O3 planes are almost parallel and the Hf atom is located 1.007 angstrom above the N4 plane and 1.476 angstrom below the O3 plane. Crystal data for [Hf(oep)Cl2(H2O].C6H6: triclinic, space group P1BAR, a = 11.977(2), b = 12.261 (1), c = 14.677 (2) angstrom, alpha = 76.74 (1), beta = 85.41 (1), gamma = 74.41 (1)degrees, Z = 2; R = 0.081 and R' = 0.092 for 3325 independent reflections with I > 3sigma(I). Crystal data for [NBun4][Hf(oep)(P3O9)].2CHCl3: monoclinic, space group P2(1)/n, a = 15.490(2), b = 19.133(1), c = 22.761(4) angstrom, beta = 99.425(7)degrees, Z = 4; R = 0.036 and R' = 0.037 for 4823 independent reflections with I > 3sigma(I).