π-Charge distribution in some (4-R1-phenyl)bis(ethylsulfonyl)methane and (4-R1-phenyl)bis(benzylsulfonyl)methane carbanions in acetonitrile

Autor:	Wlodzimierz Galezowski, Arnold Jarczewski, Iwona Binkowska
Rok vydání:	2012
Předmět:	Organic Chemistry Charge density chemistry.chemical_element Carbon-13 NMR Photochemistry Medicinal chemistry Analytical Chemistry Inorganic Chemistry chemistry.chemical_compound Delocalized electron chemistry A value Phenyl group Acetonitrile Carbon Spectroscopy Carbanion
Zdroj:	Journal of Molecular Structure. 1018:96-101
ISSN:	0022-2860
DOI:	10.1016/j.molstruc.2011.12.021
Popis:	The π-electron densities in the carbanions of (4-R 1 -phenyl)bis(ethylsulfonyl)methanes and (4-R 1 -phenyl)bis(benzylsulfonyl)methanes were calculated from 13 C NMR shifts in acetonitrile using the method of Bradamante et al. According to this analysis about half of excess π-electron density is shifted from the α-carbon to the two ethylsulfonyl or benzylsulfonyl groups. The charge delocalization over the 4-R 1 -phenyl group is relatively weak which is consistent with low sensitivity of p K a values of these carbon acids to the para substitution. Nevertheless the small changes in π charge at C α , caused by substitution on the phenyl, correlate well with the acidity of carbon acids in acetonitrile. The p K a values for nine disulfonyl carbon acids in acetonitrile have been determined by conductometric method; they fall in the range 19–24.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::bbfff5b7670d9c6910567c48a6adfacd https://doi.org/10.1016/j.molstruc.2011.12.021 Zobrazit plný text záznamu Full Text from ScienceDirect