Energetic and structural characterization of 2-R-3-methylquinoxaline-1,4-dioxides (R = benzoyl or tert-butoxycarbonyl): experimental and computational studies

• Type: Article in International Scientific Journal
• Date: 2007

Authors

Jose R B Gomes (Author) Other; Emanuel A Sousa (Author) Other; Jorge M Goncalves (Author) FCUP; Luis Gales (Author) ICBAS; Ana M Damas (Author) ICBAS; Paula Gomes (Author) FCUP; Siddharth Pandey (Author) Other; William E Acree (Author) Other; Maria D M C Ribeiro da Silva (Author) FCUP

Journal

Title: Journal of Physical Organic Chemistry

Vol. 20

Pages: 491-498

ISSN: 0894-3230

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 10 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-004-959

DOI: 10.1002/poc.1184

Abstract (EN): The gaseous standard molar enthalpies of formation of two 2-R-3-methylquinoxaline-1,4-dioxides (R = benzoyl or tert-butoxycarbonyl), at T = 298.15 K, were derived using the values for the enthalpies of formation of the compounds in the condensed phase, measured by static bomb combustion calorimetry, and for the enthalpies of sublimation, measured by Knudsen effusion, using a quartz crystal oscillator. The three dimensional structure of 2-tert-butoxycarbonyl-3-methylquinoxaline-1,4-dioxide has been obtained by X-ray crystallography showing that the two N-O bond lengths in this compound are identical. The experimentally determined geometry in the crystal is similar to that obtained in the gas-phase after computations performed at the B3LYP/6-311 + G(2d,2p) level of theory. The experimental and computational results reported allow to extend the discussion about the influence of the molecular structure on the dissociation enthalpy of the N-O bonds for quinoxaline 1,4-dioxide derivatives. As found previously, similar N-O bond lengths in quinoxaline-1,4-dioxide compounds are not linked with N-O bonds having the same strength. Copyright (c) 2007 John Wiley & Sons, Ltd.

Language: English

Type (Professor's evaluation): Scientific