Some Applications of Ultrahigh Resolution 15N NMR Spectroscopy
نویسندگان
چکیده
Ultrahigh resolution l5N NMR spectra were measured for two nitroalkanes (MeNÜ2 la, fBuN02 lc), two isocyanates (;BuNCO 2c, Me^SiNCO 2d), four isothiocyanates (MeNCS 3a, EtNCS 3b, 'BuNCS 3c, M e3SiNCS 3d), one carbodiimide (Me3 SiNCNSiMe3 4d), one keteneimine [Me3 SiNCC(SiMe3 ) 2 5d], two sulphinyl imides ('BuNSO 6c, Me3 SiNSO 6d), and N-terf-butyl-pyrrole 7c, in order to determine coupling constants J ( 15N ,I3C) and isotope induced chemical shifts 1zAl2/13C (15N) at the natural abundance of the isotopes. The values 1 Z\I2/I3C (I5N) can be separated into two groups, one dealing with NC single and another one with NC double bonds. In each group (with few exceptions), the values 1A 2/13C (l5N) become more negative with a decrease in the absolute magnitude of l'7 (l5N ,13C)l. The corresponding values ’2 r 4/l5N (l3C) show a similar behaviour. However, N-substituted pyrroles appear to be exceptional in this respect.
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