Te NMR Spectroscopy

The 33S isotope is quadrupolar (I = 3/2) and has low natural abundance (0.76%). Therefore, 33S NMR spectroscopy has found very limited application in S-N chemistry. On the other hand, both selenium and tellurium have isotopes with I = 1/2 (77Se, 7.6% and 125Te, 7.0%), and NMR studies using these nuclei can provide useful information for Se-N and Te-N systems. 

The 77Se NMR spectra can be used to analyse the composition of a complex mixture of Se-N compounds. For example, 77Se NMR provides a convenient probe for analysing the decomposition of selenium(IV) diimides RN=Se=NR (e.g., R=tBu).30 An elegant application of 77Se NMR spectroscopy, in conjunction with 15N NMR spectroscopy, involved the detection of the thermally unstable eight-membered rings (RSeN)4.31 

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Lithium alkanetellurolates and lithium benzenetellurolate react in tetrahydrofuran with sulfur, with selenium, and with tellurium to form lithium organotellurochalcogenolates. The compounds were characterized by Te-NMR spectroscopy. ... 

Lithium alkanetellurolates and benzenetellurolate reacted exothermically with an equimolar amount of selenium in tetrahydrofuran. The products were characterized by Se- and Te-NMR-spectroscopy. ... 

Only a few unsubstituted, non-stabilized alkyl tellurium halides were characterized or isolated. (-Butyl tellurium chloride may have been deteeted by Te-NMR spectroscopy as a minor product of the controlled chlorination of di-(-butyl ditellurium . 2-Chlorocarbon-ylbenzyl tellurium halides were obtained as rather unstable solids by halogenolysis of tellurophthalide (p.246). Tns[trimethylsilyl methyl tellurium chloride, bromide and iodide were isolated as black-blue crystals that were stable in solution and as solids . The stability of these compounds is attributable to the sterie proteetion of the Te—X group by the trimethylsilyl substituents. 

The presence of unsymmetrical dialkyl ditcllurium and unsymmetrical diaryl ditellurium" compounds in solution was confirmed by Te-NMR spectroscopy H-NMR spectroscopy , and mass spectroscopy . Cyclohexyl methyl ditellurium was claimed to have been isolated from a reaction mixture obtained by sequential addition of cyclohexyl bromide and methyl iodide to a solution of tetratelluride anions in dimethylformamide . The chromophoric Te —Te group in the aliphatic and aromatic ditellurium compounds imparts a characteristic orange to red color caused by an absorption maximum at approximately 400 nm. Most of the aromatic ditellurium derivatives are stable as solids toward atmospheric agents, but oxidize slowly when dissolved. The short-chain aliphatic ditellurium compounds are distillable red liquids having an obnoxious odor that clings to skin and clothes. Ditellurium compounds with more than ten carbon atoms in each aliphatic group are low melting solids that can be handled in air. 

Dimethyl tellurium in liquid hydrogen fluoride at — 70° was saturated with boron trifluoride. The dimethyl telluronium tetrafluoroborate was detected by and Te-NMR spectroscopy. ... 

All compounds were characterized by F- and Te-NMR spectroscopy and triphenyltrifluoro tellurium by single-crystal X-ray diffraction". ... 

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