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Titolo:
Spectroscopic and quantum chemical study on electronic and geometric properties of free and embedded dithizone molecules
Autore:
Schonherr, T; Linder, R; Rosellen, U; Schmid, V;
Indirizzi:
Univ Dusseldorf, Inst Theoret Chem, D-4000 Dusseldorf, Germany Univ Dusseldorf Dusseldorf Germany D-4000 em, D-4000 Dusseldorf, Germany
Titolo Testata:
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
fascicolo: 1, volume: 86, anno: 2002,
pagine: 90 - 99
SICI:
0020-7608(20020105)86:1<90:SAQCSO>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Keywords:
dithizone; tautomerism; spectroscopy; ab initio; DFT; PM3; supermolecule method;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
14
Recensione:
Indirizzi per estratti:
Indirizzo: Schonherr, T Univ Dusseldorf, Inst Theoret Chem, D-4000 Dusseldorf, Germany Univ Dusseldorf Dusseldorf Germany D-4000 sseldorf, Germany
Citazione:
T. Schonherr et al., "Spectroscopic and quantum chemical study on electronic and geometric properties of free and embedded dithizone molecules", INT J QUANT, 86(1), 2002, pp. 90-99

Abstract

The molecular and electronic structure of the three tautomeric forms of dithizone has been calculated by using semiempirical, density functional theory (DFT), and ab initio methods. Comparison of ground-state energies shows the symmetric form most stabilized, but there is only a small barrier (<3 kcal/mol) for the hydrogen transfer from N-H toward H-S (enol form). For understanding the origin of the optical transitions intermolecular interactions have to be taken into account. By using the supermolecule method, the absorption band pattern can be rationalized already on the level of the PM3 model. The nuclear magnetic resonance (NMR) solution spectrum is interpreted in terms of an equilibrium between the symmetric and the enol forms of dithizone. The appearance of strong EPR signals only for the solid state reflects a considerable lowering of the triplet state (symmetric form). Experimental features are discussed in view of calculated energies (stabilization), chemical shifts (NMR), and SOMO orbitals (EPR). (C) 2002 John Wiley & Sons,Inc.

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Documento generato il 08/04/20 alle ore 12:08:46