Pyridyl Aminophthalazine Research Articles

Synthesis, structure and characterization of new complexes [Fe 2(μ-OMe) 2(PAP)(X) 4] (PAP= 1,4-di(2 ′-pyridyl)aminophthalazine, X=Cl, OAc) and their oxidation catalysis

Two dinuclear iron(III) complexes with tetradentate N-donor ligand 1,4-di(2 ′-pyridyl)aminophthalazine (PAP), [Fe 2(μ-OMe) 2(PAP)Cl 4] ( 2) and [Fe 2(μ-OMe) 2(PAP)(OAc) 4] ( 3) were prepared and characterized. Single crystal X-ray molecular structure of [Fe 2(μ-OMe) 2(PAP)Cl 4] · 2MeOH have been elucidated. The six-coordinate iron atoms are in distorted octahedral environment bridged by the oxygen atoms of two methoxy groups and the PAP ligand. The Mössbauer spectra of both complexes show one quadrupole doublet and the isomer shift and quadrupole splitting values indicate the presence of octahedral high-spin Fe III ions. Complex 2 showed catalytic activity for alkane oxidation with hydrogen peroxide.

Copper complexes of polyfunctional phthalazines. Mononuclear and polynuclear derivatives

Mononuclear, binuclear, and trinuclear copper(II) complexes of the tetradentate ligands 1,4-di(2′-pyridyl) aminophthalazine (PAP) and 1,4-di(4′-methyl-2′-pyridyl) aminophthalazine (PAP4Me) and binuclear complexes of the tetradentate ligand 1,4-di(6′-methyl-2′-pyridyl) aminophthalazine (PAP6Me) are reported. In a series of binuclear carboxylate derivatives carboxylate bridges exist between copper centres in all cases and in some cases oxygen bridges (hydroxide or methoxide) are indicated. In all other polynuclear derivatives hydroxide bridges are anticipated on the basis of analytical, spectral, and magnetic data. The ligands exist as anionic groups in some binuclear carboxylate derivatives while in the other polynuclear systems neutral ligands are found. In reactions in aqueous solution protonated mononuclear derivatives are obtained for both PAP and PAP4Me in cases where solutions of the metal salts are inherently acidic, followed by polynuclear, neutral ligand complexes which form when the pH increases. Mononuclear protonated complexes are not obtained with PAP6Me, where steric factors may prevent the formation of such derivatives. Low magnetic moments (1.1–1.5 BM) are observed for most hydroxy bridged complexes while even lower values ( < 0.70 BM ) are observed for two binuclear complexes of PAP6Me, indicating the possibility of strong antiferromagnetic exchange between metal centres. A preliminary X-ray investigation of the complex [Cu2(PAP4Me)(OH)(NO3)2(H2O)2]NO3 indicates a triple bridged binuclear structure including a bidentate nitrate bridge and a hydroxide bridge with an oxygen bridge angle of 115.2°.