SELENIUM NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY

Abstract

The selenium resonance has boon observed and chemical shifts measured for a number of compounds. The range of shifts observed was *^1800 p.p.m. although the resonances for all molecules except HpSc were within a range of ^ 1000 p.p.n. The shift between H^ScO^ and ^Se did not agree with elchli’s result . Chemical shifts for four- and six-valent compounds are dependent on the valency and co-ordination number, but there does not api^ear to be any simple additive contribution from different ligands. Selenium-fluorine coupling constants appear to be larger for six-valent than for four-valent molecules. Selenium isotopic shifts ranging from 0.016 to 0.023 p.p.m. have been observed in the fluorine spectra of HSeOwF, SeOgF^, $e^6 ar^Adda and bassos have boon shown to shift the resonance of sqOC1p by ionisation processes involvin'; the solvent and some other offset which may be solvation. Further improvements in technique to give an increase in si. .al intensity are required before any wide application to problems in chemistry becomes possible. The hydrogen spectra of the system ScO-/^© were observed to be very similar to those of SO^/H^C.