11 research outputs found
Erratum: Theoretical structures and experimental vibrational spectra of isomeric benzofused thieno [3,2-b] furan compounds (Journal of Molecular Structure (2010) 967 (1-3) (159-165))
Fil: Ledesma, Ana Estela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Tucuman. Facultad de BioquĂmica, QuĂmica y Farmacia. Instituto de QuĂmica FĂsica. CĂĄtedra de FisicoquĂmica I; ArgentinaFil: Contreras, C.. Universidad Nacional de Tucuman. Facultad de BioquĂmica, QuĂmica y Farmacia. Instituto de QuĂmica FĂsica. CĂĄtedra de FisicoquĂmica I; ArgentinaFil: Svoboda, J.. Institute of Chemical Technology; RepĂșblica ChecaFil: Vektariene, A.. Institute of Theoretical Physics and Astronomy of Vilnius University; LituaniaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucuman. Facultad de BioquĂmica, QuĂmica y Farmacia. Instituto de QuĂmica FĂsica. CĂĄtedra de FisicoquĂmica I; Argentin
Two Faces of Ciprofloxacin: Investigation of Proton Transfer in Solid State Transformations
Quantum chemical, experimental exploration of biological activity and inhibitory potential of new cytotoxic kochiosides from Kochia prostrata
Interaction of derivatives of 7-amino-1,5-benzo-diazepin-2-ones with α,ÎČ-unsaturated ketones
Regio- and Stereoselectivity in the 1,3-Dipolar Cycloaddition Reactions of Isoquinolinium Ylides with Cyclopenta[a]acenaphthylen-8-ones
QSRR-based estimation of the retention time of opiate and sedative drugs by comprehensive two-dimensional gas chromatography
DFT study on structure, electronic properties, and reactivity of cis-isomers of [(NC5H4-S)2Fe(CO)2]
Arene-fused 1,2-oxazole N-oxides and derivatives. The impact of the N-O dipole and substitution on their aromatic character and reactivity profile. Can it be a useful structure in synthesis? A theoretical insight
DFT calculations have shown that the N-O dipole of benzene- and naphthalene-fused 1,2-oxazole N-oxides causes a distortion of their Ï and Ï frame, concentrated on the 1,2-oxazole ring, such that it increases its susceptibility to opening. The distortion forces the benzene ring into some diene geometry, thus, reducing Ï delocalization over the bi- or tricyclic structure and ultimately their aromatic character. C-3 substitution has a marked influence mainly on the naphthalene-fused N-oxides. C-5 and particularly C-6 substitution, as the position of most extended interaction with the N-O dipole through the Ï ring density, contribute to the distortion of the 1,2-oxazole geometry and thereby to the decrease of aromaticity of the structure. Bond uniformity (IA), average bond order (ABO) and Harmonic Oscillator Model of Aromaticity (HOMA) indices have been recruited to measure aromaticity changes. IA and ABO appear to be more credible to 1,2-benzoxazole N-oxides and 1,2-naphthoxazole N-oxides, respectively, while HOMA has been found equally reliable to both. Hardness and dipole moments follow similar trends. Energies, localization and separation of the four frontiers orbitals, i.e. HO, HO-1, and LU, LU+1, indicate a rather notable aromatic character of the N-oxides. Their reactivity profile, portrayed by descriptors such as Fukui and electro(nucleo)philicity Parr functions, shows good agreement with experimental outcomes towards electrophiles but succumbs to discrepancies towards nucleophiles due to the susceptibility of the hetero-ring to opening. The "push-pull" character of the N-O dipole and more importantly the extent of its double bonding direct site selectivity.Peer reviewe