| | 1 | Author
| Paul Haake, DonaldA. Tyssee | Requires cookie* | | | Title
| Estimation of Charge Density on Nitrogen in Amides by Measurement of One-Bond Carbon-Hydrogen Nuclear Coupling Constants in N-CH 3 Group* *  | | | | Abstract
| One-bond, 13 C-X H coupling constants, Jj(C-H), in amines, ammonium ions, and carboxylic amides correlate with structure and support the concept that the value of J^C-H) is related to the charge density on the nitrogen atom; for example, amine oxides have nearly the same charge density at nitrogen as does the tetramethylammonium ion. The Jj(C-H) values for methyls bonded to nitrogen in various amides then give an experimental estimate of the charge density at the nitrogen atom that enables an estimate of the bond order in the C-N amide-bond; the data suggest that carboxylic amides have a C-N bond order of about 1.35, that sulfonamides have an S-N bond order of about 1.45, and that phosphinamides, R 2 P(0)N(CH 3) 2 , have a P-N bond order of about 1.3. In contrast, aminephosphines have a P-N single bond. The value for carboxylic amides is in reasonable agreement with bond distances in amides. | | | |
Reference
| Z. Naturforsch. 48a, 58—62 (1993); received November 26 1991 | | | |
Published
| 1993 | | | |
Keywords
| Amides, Amine oxides, Charge density at nitrogen, Sulfonamides, Phosphinamides | | | |
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| default:Reihe_A/48/ZNA-1993-48a-0058.pdf | | | | Identifier
| ZNA-1993-48a-0058 | | | | Volume
| 48 | |
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