Dimethyl 2,2`-[(4-oxo-2-phenyl-4H-chromene-5,7-diyl)dioxy]diacetate:a less densely packed polymorph

Nallasivam, Angannan and Nethaji, Munirathinam and Vembu, Nagarajan and Jaswant, Buckle and Sulochana, Nagarajan (2009) Dimethyl 2,2`-[(4-oxo-2-phenyl-4H-chromene-5,7-diyl)dioxy]diacetate:a less densely packed polymorph. In: Acta Crystallographica Section E-Structure Reports Online, 65 (Part 2). O314-U2075.

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Abstract

The title molecule, C21H18O8, crystallizes in two crystal polymorphs,see also Nallasivam, Nethaji, Vembu & Jaswant [Acta Cryst. (2009),E65, o312-o313]. The main difference between the two polymorphs is in the conformation of the oxomethylacetate groups with regard to the almost planar [total puckering amplitude 0.047 (2) angstrom] chromene ring. In the title compound, the best planes of the oxomethylacetate groups through the non-H atoms are almost perpendicular to the chromene ring [making dihedral angles of 89.61 (6) and 80.59 (5)degrees], while in the second polymorph the molecules are close to planar. Both crystal structures are stabilized by C-H center dot center dot center dot O.

Item Type:	Journal Article
Publication:	Acta Crystallographica Section E-Structure Reports Online
Publisher:	International Union of Crystallography
Additional Information:	Copyright of this article belongs to International Union of Crystallography.
Keywords:	single-crystal X-ray study; T = 293 K; mean _(C–C) = 0.003 A°;R factor = 0.055; wR factor = 0.140; data-to-parameter ratio = 16.3.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	26 Aug 2009 04:38
Last Modified:	19 Sep 2010 05:28
URI:	http://eprints.iisc.ac.in/id/eprint/19366

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