ISSN:
0030-4921
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The C—H proton NMR spectra of the twenty conceivable methyl and ethyl substituted hydrazines are presented and analyzed with respect to effects on chemical shifts of the C—H protons caused by replacement of hydrogen by methyl and ethyl groups on the C—N—N—C chain. Thirteen different methyl substituent effects and six different ethyl substituent effects are identified and evaluated. Most of the effects are shielding and in accordance with an electron-releasing inductive effect of alkyl groups. A deshielding effect (the ‘C—C bond effect’) is observed when a methyl group replaces the hydrogen on the carbon bearing the hydrogen in focus and primary hydrogen on the carbon bearing the hydrogen in focus and primary hydrogens become secondary, as observed in other systems. On the basis of their effects on the chemical shifts of methyl protons in CH3X, eighteen different hydrazyl groups (× = —NR1NR2R3) fall into three classes: I (R1 = H; R2, R3 = H or alkyl); II (R1 = alkyl; R2 and/or R3 = H); III (R1, R2 and R3 = alkyl), with slightly different electronegativities: 2·94, 2·83 and 2·74, respectively.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1270061002
