Elizabeth A. Hansen

Application of Low‐Field NMR to the Unambiguous Assignment of Spin‐Coupling Parameters. III. Other Pentafluorobenzenes

The 6.14‐MHz fluorine NMR spectra were employed in removing ambiguities in the signs and assignments of coupling constants in C6F5–Cl, –Br, –CN, –COOH, –COCl, –OH, –NH2, and –SO2Cl. Except for C6H5OH, selection of the correct parameter set entailed only a visual comparison of the low‐field spectrum and computed spectra based on permutations of the nonassignable parameters from high‐field studies. The correct parameter sets were subsequently computer refined to obtain best fits to the 6.14‐MHz spectra. However, in the case of C6F5OH, the solvent dependence of the spectrum necessitated computer iterative analysis of the 6.14‐MHz data to arrive at the correct parameter set. For C6F5COCl, high‐precision 94.1‐MHz spectra were of use in eliminating all but one uncertainty in the assignments. The Abraham–MacDonald–Pepper linear relationship involving the ortho–ortho substituent contribution and the Hammett σp constant was modified and extended to yield for the compounds C6F5–X the relationship J26(Hz) = − 9.5σp(...

The isolation and identification of a new hetero ring system : The fusion of captan [N-(trichloromethylthio)-4-cyclohexene-1,2-dicarboximide] with resorcinol to give [1,2] benzoxathiolo [2,3-b][1,2] benzoxathiole-6-SIV-3,9-diol☆

Abstract A novel heterocyclic structure, [1,2] benzoxathiolo [2,3- b ] [1,2] benzoxathiole-6- S IV-3.9-diol (IIIa), has been identified as a product from fusion of resorcinol with the fungicide captan. Mass, NMR, UV and IR spectral properties, as well as chemical evidence, are reported in support of structure IIIa.

Nuclear Magnetic Resonance Tube Washer

Washing of expensive nuclear magnetic resonance (NMR) tubes has been a problem; washing each tube by hand can be time consuming and awkward. Akkerman reported a device which allows the tubes to be cleaned by a batch process. The tube washer described in the present paper was developed on similar principles, but has several advantages: Filling the tubes with cleaning fluids is more convenient, the washer can be emptied and the tubes dried very easily, and breakage of the tubes during the cleaning process has been greatly reduced.

The complete analysis of the 19F nuclear magnetic resonance spectrum of octafluorostyrene

A complete analysis of the 19F n.m.r. spectrum of the eight-spin octafluorostyrene system is presented.