Synthesis and spectral studies of iron(III) and iron(II) complexes with 2,3-disubstituted quinazolin-4(3H)-ones

A number of Fe(III) and Fe(II) complexes of some O-N-O donors and bidentate O-O, and O-N donors in the form of 2,3-disubstituted quinazolin-4(3H)-ones have been synthesized and characterized based on analytical, conductivity, thermal, magnetic and infrared, electronic and Mossbauer spectral data. Th e analytical data of Fe(III) complexes with all the ligands with the except ion of 2-methyl-3-carboxymethyl quinazolin-4(3H)- one (MCMQ) and 2-phenyl-3 -carboxymethyl quinazolin-4(3H)- one (PCMQ), and all the complexes of Fe(II ) show 1:2 (metal:ligand) stoichiometry. However, Fe(III) complexes of MCMQ and PCMQ are in 1:3 stoichiometry. The IR spectral data of complexes indic ate that the ligands MHBQ and PHBQ act as uninegative tridentate and MCMQ a nd PCMQ act as uninegative bidentate ligands. The ligands viz 2-methyl-3-am ine quinazolin-4(3H)-one (MAQ), 2-phenyl-3-amine quinazolin-4(3H)- one (PAQ ), 2-methyl-3-uramino quinazolin-4(3H)- one (MUQ), 2-phenyl-3-uramino quina zolin-4(3H)- one (PUQ), 2-methyl-3-thiouramino quinazolin-4(3H)- one (MTUQ) and 2-phenyl-3-thiouramino quinazolin-4(3H)- one (PTUQ) act as neutral bid entate ligands. Octahedral geometry has been proposed for all the complexes based on electronic and Mossbauer spectral data.