13C Fourier Transform Nuclear Magnetic Resonance. XI. Pyridine N-Oxide Derivatives

Fourier Transform Carbon - 13 Nuclear Magnetic Resonance Study of LnNi ( CO ) 4 - n Derivatives

13C N M R spectra have been obtained f0r.a series of LnNi(CO)o-n derivatives (n = 0-3) where L = PR3, PPhzY, PPhY2, P(OR')3, and Pc13 (R = Me, Et, Bu, Ph; R' = Me, Et, l-Pr, Ph; Y = C1, Me, OMe, OPh). The effect upon the carbonyl chemical shift of the replacement of X by Y substituents in X3-nYnPNi(C0)3 derivatives appears to be additive, as is the effect of the sequential replacement of carbon...

Fourier Transform Multiple Quantum Nuclear Magnetic Resonance

The excitation and detection of multiple quantum transitions in systems of coupled spins offers, among other advantages, an increase in resolution over single quantum n.m.r. since the number of lines decreases as the order of the transition increases. This paper reviews the motivation for detecting multiple quantum transitions by a Fourier transform experiment and describes an experimental appr...

Carbon-13 Fourier transform nuclear magnetic resonance. II. Ribonuclease.

High-resolution Fourier transform nuclear magnetic resonance was used to observe the natural abundance (13)C spectrum of a 0.02 M solution of bovine pancreatic ribonuclease A. Peaks assignable to only three carbons were easily observed after 10 hr of signal averaging. A number of tentative assignments were made. As expected, the (13)C spectrum was appreciably richer in detail than the correspon...

Nuclear Magnetic Resonance Fourier Transform Spectroscopy ( Nobel Lecture ) 1 Richard

13C-nuclear magnetic resonance investigations of xanthine and some of its N-methylated derivatives.

The 13C-Nuclear Magnetic Resonance spectra of xanthine, 1,3-dimethyl-xanthine (theophylline), 3,7-dimethyl xanthine (theobromine) and 1,3,7-trimethylxanthine (caffeine) were obtained and the lines assigned. Protonationand N-Methylation parameters are derived by comparison of the 13C-chemical shifts of the protonated cations with those of the neutral molecules and also with those of the xanthine...