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Hetero-π-systems from 2 + 2 cycloreversion, part 2.1Ab initio thermochemical study of heterocyclobutanes 2 + 2 cycloreversion to form heteroethenes H2C=X (X=NH, O, SiH2, PH, S)

✍ Scribed by Leonid E. Gusel'nikov; Vitaly G. Avakyan; Stephan L. Guselnikov

Publisher: John Wiley and Sons
Year: 2007
Tongue: English
Weight: 477 KB
Volume: 18
Category: Article
ISSN: 1042-7163
DOI: 10.1002/hc.20377

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✦ Synopsis

Ab initio and DFT thermochemical study of diradical mechanism of 2 + 2 cycloreversion of parent heterocyclobutanes and 1,3-diheterocyclobutanes, cyclo-(CH 2 CH 2 CH 2 X), and cyclo-(CH 2 XCH 2 X), where X = NH, O, SiH 2 , PH, S, was undertaken by calculating closed-shell singlet molecules at three levels of theory: MP4/6-311G(d)// MP2/6-31G(d)+ZPE, MP4/6-311G(d,p)//MP2/6-31G (d,p)+ZPE, and B3LYP/6-311+G(d,p)+ZPE. The enthalpies of 2 + 2 cycloreversion decrease on going from group 14 to group 16 elements, being substantially higher for the second row elements. Normally endothermic 2 + 2 cycloreversion is predicted In memory of Dr. Vera V. Volkova without whom the world became a little less bright.

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