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Polynuclear Magnetic Resonance of Substituted Thiobenzanilides and Benzanilides: Transmission of Substituent Effects through the Thiocarboxamide Group
Author(s) -
Waisser Karel,
Kuneš Jiří,
Kubicová and Lenka,
Buděšínský Miloš,
Exner Otto
Publication year - 1997
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/(sici)1097-458x(199708)35:8<543::aid-omr126>3.0.co;2-5
Subject(s) - substituent , chemistry , polarizability , group (periodic table) , resonance (particle physics) , nitrogen , acceptor , crystallography , computational chemistry , stereochemistry , organic chemistry , molecule , atomic physics , physics , condensed matter physics
The 1 H, 13 C and 19 F NMR spectra of 3′‐ and 4′‐substituted 3‐ and 4‐fluorobenzanilides and thiobenzanilides are reported. According to the 19 F substituent‐induced shifts (SCS), transmission of substituent effects through the NHCS group is less efficient than that through NHCO groups. On the other hand, in thioanilides a greater part of the substituent effect remains on the functional group itself, as follows mainly from 13 C SCS of the central carbon. An explanation is possible in terms of the greater polarizability of sulfur, which accommodates charge better than oxygen. Comparison with the isomers studied previously reveals that transmission depends slightly on the direction. It is more efficient through the NHCX group than through the CXNH group: the nitrogen atom as donor interacts more strongly than carbonyl with the substituent effects of acceptor groups. © 1997 John Wiley & Sons, Ltd.