Synthesis, spectral, structural, DFT and NLO studies of cerium(III) and thorium(IV) complexes of 1-(5-(1-(2-aminophenylimino)ethyl)-2,4-dihydroxyphenyl)ethanone

Abstract

Reactions of cerium(III) and thorium(IV) nitrates with the Schiff base 1-(5-(1-(2-aminophenylimino)ethyl)-2,4-dihydroxyphenyl)ethanone (H2L) gave two neutral mononuclear complexes, [Ce(HL)(NO3)2(H2O)]·EtOH (1) and [Th(HL)(NO3)3(H2O)]·6H2O (2), respectively. The complexes were characterized by elemental and thermal analyses, IR, electronic, 1H NMR and mass spectra, molar conductivity and magnetic susceptibility measurements. Analytical and spectroscopic methods illustrated that the Schiff base acts as a monoanionic tridentate N2O-ligand. This paper shows a correlation between the structure of the cerium(III) and thorium(IV) complexes experimentally and theoretical study on molecular structure, thermo-chemical parameters and the harmonic vibration frequencies of them. The geometrically optimized structures of the complexes are non-planar. HOMO and LUMO gap energy is small, the charge transfer occurring within cerium(III) and thorium(IV) complexes indicates a greater reactivity and conversely, low chemical stability.