Crystal packing and melting temperatures of small oxalate esters: the role of C-H center dot center dot center dot O hydrogen bonding

Joseph, Sumy and Sathishkumar, Ranganathan and Mahapatra, Sudarshan and Desiraju, Gautam R (2011) Crystal packing and melting temperatures of small oxalate esters: the role of C-H center dot center dot center dot O hydrogen bonding. In: Acta Crystallographica Section B, 67 (Part 6). pp. 525-534.

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Abstract

The simple dialkyl oxalates are generally liquids at room temperature except for dimethyl and di-tert-butyl oxalate which melt at 327 and 343 K. The crystal structures of diethyl, di-iso-propyl, di-n-butyl, di-tert-butyl and methyl ethyl oxalates were determined. The liquid esters were crystallized using the cryocrystallization technique. A comparison of the intermolecular interactions and packing features in these crystal structures was carried out. The crystal structure of dimethyl oxalate was redetermined at various temperatures. The other compounds were also studied at several temperatures in order to assess the attractive nature of the hydrogen bonds therein. A number of moderate to well defined C-H center dot center dot center dot O interactions account for the higher melting points of the two solid esters. Additionally, a diminished entropic contribution Delta S(m) in di-tert-butyl oxalate possibly increases the melting point of this compound further.

Item Type:	Journal Article
Publication:	Acta Crystallographica Section B
Publisher:	International Union of Crystallography
Additional Information:	Copyright of this article belongs to International Union of Crystallography.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	19 Dec 2011 11:53
Last Modified:	19 Dec 2011 11:56
URI:	http://eprints.iisc.ac.in/id/eprint/42769

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