Document Details

Document Type : Article In Journal 
Document Title :
Twisting and planarization in push-pull ethylenes
الألتواء وثنائية القطبية في الأثيلينات
 
Subject : Organic Chemistry 
Document Language : English 
Abstract : As determined by X-ray crystallography, Meldrum's acid derivatives 8-19 feature dihedral angles around the central C=C double bonds between 3 and 83°. Hydrogen bonds between substituents RHN and the carbonyl groups favour near-planarity. Sterically demanding substituents favour large dihedral angles and zwitterionic structures as in formula 20. AM1 calculations of the structures are in excellent agreement with the experimental X-ray data, provided a dielectric field is incorporated (ε = 40). This can be ascribed to the highly polar (zwitterionic) nature of the molecules. It is further predicted that all these molecules, including those that are stabilised in a planar form by intramolecular hydrogen bonds, undergo rapid rotation about the central C=C bonds at room temperature. DFT calculations incorporating a dielectric field model (PCM) are in excellent agreement with the near-perpendicular arrangement of the alkene moiety in 19. 
ISSN : 14701820 
Journal Name : Journal of the Chemical Society, Perkin Transactions 2 
Volume : 2 
Issue Number : 2 
Publishing Year : 1423 AH
2002 AD 
Article Type : Article 
Added Date : Wednesday, December 22, 2010 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
بول برنهارت فان كوخ كيرت وينترابWentrup, C, Bernhardt, P V., KochResearcherDoctoratemajedshtaiwi@yahoo.co.uk

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