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Εξειδίκευση τύπου : Άρθρο σε επιστημονικό περιοδικό
Τίτλος: 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
Δημιουργός/Συγγραφέας: Kozielewicz P.
Tzeli D.
Tsoungas P.G.
Zloh M.
Εκδότης: Springer New York LLC
Ημερομηνία: 2014
Γλώσσα: Αγγλικά
ISSN: 1040-0400
DOI: 10.1007/s11224-014-0459-6
Περίληψη: DFT calculations have shown that the N-O dipole of benzene- and naphthalene-fused 1,2-oxazole N-oxides causes a distortion of their σ and π 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 π 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 π ring density, contribute to the distortion of the 1,2-oxazole geometry and thereby to the decrease of aromaticity of the structure. Bond uniformity (I A), average bond order (ABO) and Harmonic Oscillator Model of Aromaticity (HOMA) indices have been recruited to measure aromaticity changes. I A 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.
Τίτλος πηγής δημοσίευσης: Structural Chemistry
Τόμος/Κεφάλαιο: 25
Τεύχος: 6
Σελίδες: 1837-1846
Θεματική Κατηγορία: [EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistrysemantics logo
Λέξεις-Κλειδιά: Aromaticity
Benzo-fused 1 2-oxazole N-oxide
Derivatives of 1 2-oxazole N-oxides
DFT calculations
Naphtho-fused 1 2-oxazole N-oxide
Αξιολόγηση από ομότιμους (peer reviewed): Ναι
Κάτοχος πνευματικών δικαιωμάτων: © 2014 Springer Science+Business Media New York.
Εμφανίζεται στις συλλογές:Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο

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