Dinuclear oxidovanadium(V) complexes incorporating N, N, O, O coordinating ligands: Synthesis, structure, spectral, DFT and TDDFT study

• Published in: Polyhedron Vol. 54; pp. 228 - 236
• Main Authors: Mondal, Pallab, Hens, Amar, Rajak, Kajal Krishna
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 30.04.2013; Elsevier
• Subjects: Chemistry; Chemistry, Inorganic & Nuclear; Crystallography; DFT studies; Oxidovanadium(V) complexes; Physical Sciences; Science & Technology; Spectral study; X-ray structure; Spectral study; DFT studies; Oxidovanadium(V) complexes; X-ray structure; OXIDATION; CONSISTENT PERTURBATION-THEORY; SPECTROSCOPIC PROPERTIES; OXOVANADIUM(V) COMPLEXES; REACTIVITY; VANADIUM; SCHIFF-BASES; CHEMISTRY; DENSITY-FUNCTIONAL THEORY; BINDING
• ISSN: 0277-5387; 1873-3719
• DOI: 10.1016/j.poly.2013.02.048

Three new dinuclear oxidovanadium(V) complexes have been synthesized using N, N, O, O coordinating ligands. The complexes are isolated and characterized by different spectroscopic techniques. X-ray structure of a representative complex has been determined. The electronic structure, absorption and CD spectra of the complexes were calculated applying DFT-TDDFT method. The chemical shift was also computed using GIAO-DFT calculation. The occupancies and composition of the natural bond orbitals (NBOs) for all the complexes were also calculated using DFT. Dinuclear (VVVV) oxidovanadates of general formula [V2O3(L)2] have been synthesized in excellent yields by reacting bis(acetylacetonato)oxidovanadium(IV) with H2L in a 1:1 ratio in acetonitrile in air. Here L2− is the deprotonated form of 2-[((2-hydroxypropan-2-yl)(pyridin-2-ylmethyl)amino)methyl]phenol (H2L1), 2-[((1-hydroxy-2-methylpropyl)(pyridin-2-ylmethyl)amino)methyl]phenol (H2L2) and 2-[((1-hydroxy-3-methylbutyl)(pyridin-2-ylmethyl)amino)methyl]phenol (H2L3). X-ray crystallographic study for the complex 1 reveals that the relative disposition of the two VO groups in [V2O3(L1)2] is almost cis, the O6V1—V2O7 torsion angle being 42.9(2)°. Low VV/VIV reduction potentials (−0.50V versus SCE) are indicative of the considerable VO3+ stabilization due to alkoxide coordination. The gas-phase geometry optimization and the electronic structures of [V2O3(L1)2], 1; [V2O3(L2)2], 2 and [V2O3(L3)2], 3 have been investigated with the framework of density functional theory. The absorption spectra of the complexes and the CD spectra for 2 and 3 are calculated by time dependent density functional theory (TDDFT) using conductor like polarizable continuum model (CPCM). DFT calculation shows a good agreement to the experimental ground state IR and NMR value.