Photocolouration of 2,4,4,6-Tetraaryl-4H-pyrans and Their Heteroanalogues: Importance of Hypervalent Photoisomers

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Title:Photocolouration of 2,4,4,6-Tetraaryl-4H-pyrans and Their Heteroanalogues: Importance of Hypervalent Photoisomers
Creators:
Böhm, Stanislav
Adamec, Mojmír
Nešpůrek, Stanislav
Kuthan, Josef
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 60, 10, pp. 1621-1633

Abstract

<p>Molecular geometries of 2,4,4,6-tetraphenyl-4<i>H</i>-pyran (<i>Ia</i>), 4,4-(biphenyl-2,2e-diyl)-2,6-diphenyl-4<i>H</i>-pyran (<i>Ib</i>) and their heterocyclic isomers <i>II</i>-<i>V</i> were optimized by the PM3 method and used for the calculation of electronic absorption spectra by the CNDO/S-CI procedure. Comparison of the theoretical data with experimental UV-VIS absorption spectra made possible to select hypervalent molecules <i>IIIa</i>, <i>IIIb</i>, <i>IVa</i> and <i>IVb</i> being responsible for the photocolouration of 4<i>H</i>-pyrans <i>Ia</i>, <i>Ib</i>, while compounds <i>Va</i>, <i>Vb</i>, <i>VI</i> and <i>VII</i> come into account as possible photodegradation products. The bleaching process of the UV illuminated compound <i>Ia</i> is analyzed in terms of dispersive first-order reaction kinetics.

Title:Photocolouration of 2,4,4,6-Tetraaryl-4H-pyrans and Their Heteroanalogues: Importance of Hypervalent Photoisomers
Creators:
Böhm, Stanislav
Adamec, Mojmír
Nešpůrek, Stanislav
Kuthan, Josef
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:60
Number:10
Page Range:pp. 1621-1633
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19951621UNSPECIFIED
ID Code:857
Item Type:Article
Deposited On:06 Feb 2009 17:04
Last Modified:06 Feb 2009 16:04

Citation

Böhm, Stanislav; Adamec, Mojmír; Nešpůrek, Stanislav; Kuthan, Josef (1995) Photocolouration of 2,4,4,6-Tetraaryl-4H-pyrans and Their Heteroanalogues: Importance of Hypervalent Photoisomers. Collection of Czechoslovak Chemical Communications, 60 (10). pp. 1621-1633. ISSN 0010-0765

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