Vishnumunhy, Kodumuru and Row, Tayur Guru N and Venkatesan, Kailasam (1999) Studies in crystal engineering: Steering ability of fluorine in styrylcoumarins. In: Tetrahedron, 55 (13). pp. 4095-4108.
PDF
Studies_in_Crystal_Engineering_Steering.pdf - Published Version Restricted to Registered users only Download (662kB) | Request a copy |
Abstract
In continuation of our studies on crystal engineering using fluorine as a steering group, the photobehaviour of di and tri fluoro 4-styrylcoumarins has been examined. It is found that out of the five derivatives, four crystallize into P-packing mode producing syn-HH photodimer upon irradiation whereas the parent hydrocarbon produces an anti K-T dimer. The packing features of the photolabile crystals of 4-(4-fluorostyryl)-6-fluorocoumarin (1), 4-(2,6-difluorostyryl) 6-fluorocoumarin (2) and the photodimer (3a) of 4-(2,6-fluorostyryl)-7-fluorocoumarin (3) have been determined by single crystal X-ray diffraction studies. The stereochemistry of the photodimer of 4-(2-fluorostyryl)-6-fluorocoumarin (4) is deduced based on preliminary X-ray crystallographic data. However, 4-(2,6-difluorostyryl) coumarin (5) is photoinert. The remarkable steering ability of fluorine is established with the molecular packing in the crystal lattice leading to the formation of syn H-H dimer in the above four examples. (C) 1999 Elsevier Science Ltd. All rights reserved.
Item Type: | Journal Article |
---|---|
Publication: | Tetrahedron |
Publisher: | Elsevier Science |
Additional Information: | Copyright of this article belongs to Elsevier Science. |
Department/Centre: | Division of Chemical Sciences > Organic Chemistry Division of Chemical Sciences > Solid State & Structural Chemistry Unit |
Date Deposited: | 30 Jun 2011 07:20 |
Last Modified: | 30 Jun 2011 07:20 |
URI: | http://eprints.iisc.ac.in/id/eprint/38806 |
Actions (login required)
View Item |