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Application of DFT Methods in the Study of V IV O 2+ –Peptide Interactions
Author(s) -
Micera Giovanni,
Garribba Eugenio
Publication year - 2010
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201000382
Subject(s) - chemistry , crystallography , amide , deprotonation , molecular orbital , density functional theory , electron paramagnetic resonance , homo/lumo , imine , atomic orbital , natural bond orbital , vanadium , computational chemistry , inorganic chemistry , molecule , nuclear magnetic resonance , electron , ion , organic chemistry , physics , quantum mechanics , catalysis
Abstract V IV O 2+ complexes formed by histidylglycylglycine (HisGlyGlyH), glycylglycylhistidine (GlyGlyHisH), glycylglycylcysteine (GlyGlyCysH 2 ), N ‐glycyl‐bis(imidazol‐2‐yl)methylamine (Gly–BIMA), N ‐glycyl‐bis(pyridin‐2‐yl)methylamine (Gly–BPMA), salicylglycyl‐ L ‐alanine (SalGly‐ L ‐AlaH 2 ) and 1,2‐bis(2‐hydroxybenzamido)benzene (H 2 hybeb) in their fully deprotonated form were studied by density functional theory (DFT) methods. They are characterised by different total electric charges, total equatorial charges and number of V–N – amide bonds. DFT calculations enable structural features, like V–donor bond lengths, and spectroscopic features, like electron paramagnetic resonance (EPR) and electronic absorption parameters, to be calculated. The results suggest that an amide group coordinates vanadium in the“amide‐” rather than the “imine‐like” form with the nitrogen atom negatively charged and with a double bond between the carbon and oxygen atoms of the carbonyl group, and that the equatorial charge is delocalised among all the donors bound to vanadium (O oxido included). The analysis of the molecular orbital composition reveals that the d xy orbital is the vanadium orbital at lower energy, that it can participate in a π bond with the nitrogen p z orbital of the amide groups, that the vanadium d xz and d yz orbitals are involved in a large π interaction with the oxido p x and p y orbitals and that differences in the donor strengths of the ligands and deviations from the ideal square‐pyramidal symmetry can result in the separation of the energies of the vanadium d xz and d yz orbitals.