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. The analytical data of Fe(III) complexes with all the ligands with the exception 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 indicate that the ligands MHBQ and PHBQ act as uninegative tridentate and MCMQ and PCMQ act as uninegative bidentate ligands. The ligands viz 2-methyl-3-amine 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 quinazolin-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 bidentate ligands. Octahedral geometry has been proposed for all the complexes based on electronic and Mossbauer spectral data.