KAPIČKA, Libor, Pavel KUBÁČEK a Petr HOLUB. Bonding and aromaticity of cyclic phosphazenes viewed as interaction of Dnh fragments. Journal of Molecular Structure (Theochem), Amsterdam: Elsevier Science, 2007, roč. 820, 1-3, s. 148-158. ISSN 0166-1280.
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Základní údaje
Originální název Bonding and aromaticity of cyclic phosphazenes viewed as interaction of Dnh fragments
Autoři KAPIČKA, Libor (203 Česká republika), Pavel KUBÁČEK (203 Česká republika, garant, domácí) a Petr HOLUB (203 Česká republika, domácí).
Vydání Journal of Molecular Structure (Theochem), Amsterdam, Elsevier Science, 2007, 0166-1280.
Další údaje
Originální jazyk angličtina
Typ výsledku Článek v odborném periodiku
Obor 10403 Physical chemistry
Stát vydavatele Česká republika
Utajení není předmětem státního či obchodního tajemství
WWW URL
Impakt faktor Impact factor: 1.112
Kód RIV RIV/00216224:14310/07:00032396
Organizační jednotka Přírodovědecká fakulta
UT WoS 000250354000022
Klíčová slova anglicky Cyclic phosphazenes; Aromaticity; Orbital interactions; Potential energy surface
Štítky aromaticity, Cyclic phosphazenes, Orbital interactions, potential energy surface
Příznaky Mezinárodní význam, Recenzováno
Změnil Změnil: doc. RNDr. Petr Holub, Ph.D., učo 3248. Změněno: 29. 4. 2020 21:48.
Anotace
The qualitative molecular orbital approach based on orbital interactions was used to explore the nature of bonding in cyclic fluorophosphazenes (F2PN)n, where n is 2-6. Besides the classical skeleton of sigma-bonds, only two, one radial and one axial, 2n-center two-electron pi-bonds significantly participate in the extra stabilization of the (PN)n ring. The pi-radial interaction is more effective and comparable by size with the sigma ones. Additional slight stabilization of a (PN)n ring is achieved by nonbonding pi-radial and pi-axial molecular orbitals (MOs) which are mainly localized on nitrogen atoms. The orbital interactions have a hyperconjugation character. The bonding energy decomposition analysis showed that the cyclic interactions are about half covalent and half electrostatic. The covalent bonding is dominated by radial interactions. The aromaticity concept is not appropriate for description of bonding in cyclophosphazenes. The contribution of phosphorus d atomic orbitals to the concept of chemical bonding in phosphazenes is negligible, but the inclusion of d phosphorus functions in a basis set is appropriate for a correct quantitative description of electronic and geometric structure. Extended Hückel (EHT), ab initio and density functional (DFT) calculations provide the same qualitative picture of the bonding. The very flat B3LYP/6-311+G(3df)//B3LYP/6-31G(3df) potential energy surface (PES) with the low energy barrier (1.6 kJ mol-1) indicates the very fast and easy conformational motion of (F2PN)4. The global minimum on this PES is the S4 conformation.
VytisknoutZobrazeno: 4. 12. 2020 18:40