✍ Scribed by W. McFarlane; A. Noble; J. Winfield
No coin nor oath required. For personal study only.
In contrast with the behaviour of many coupling constants. lJ(19%-19~) can change sign. without an accompanying change in the valence of tungsten: the two W-F coupling constants have the same sign in MeOWF5 and related compounds, but they have opposite signs in the WOF< anion.
📜 SIMILAR VOLUMES
## Abstract The signs of all ^13^C^19^F and ^1^H–^19^F coupling constants in fluorobenzene, some substituted derivatives, and in 2‐fluoropyridine have been related using single‐frequency ^13^C{^1^H} double resonance techniques. All ^13^C^19^F couplings in these compounds are shown to be positive
The sign 'J(NN) of 2-chlor0-6-methyl-['~N,]pyrimidine has been determined by 'H-('H (selective), "N (selective)} and 13C-(1H (noise), I5N (selective)} triple resonance techniques. The sign was proved to be negative (-1.6 Hz); consequently, chlorine substitution at C-2 was found to make ' . I ( " ) m
## Only pomt densI& are sampIed when matnx elements of a delta funclron operator are evaluated Thus, the Ferrm contact contnbution to nuclear spin-spin couphng tensors IS very senslhve IO local ma ccurac~es of the wavefunctloas An alternauve expresslon for the delta function wiuch uses a global re