Functionalized Tellurols: Synthesis, Spectroscopic Characterization by Photoelectron Spectroscopy, and Quantum Chemical Study

Abstract

Ethene-, cyclopropane-, 3-butene-, and cyclopropanemethanetellurol have been synthesized by reaction of tributyltin hydride with the corresponding ditellurides and characterized by 1H, 13C, and 125Te NMR spectroscopy and high-resolution mass spectrometry. The tellurols of this series, with a gradually increasing distance between the tellurium atom and the unsaturated group, have been studied by photoelectron spectroscopy and quantum chemical calculations. Two stable conformations of ethenetellurol and cyclopropanetellurol, five of allyltellurol, and four of cyclopropanemethanetellurol were found. In the photoelectron spectrum of vinyltellurol, the huge split between the first two bands indicates a direct interaction between the tellurium lone electron pair and the double bond. In the allyl derivative, a hyperconjugation effect was found for the most stable conformers. In contrast to the vinyl compounds, no direct interaction between the lone electron pair of X (X = O, S, Se, and Te) and the three-membered ring could be observed in the cyclopropyl derivatives. A hyperconjugation-like effect, which is independent of the relative orientation of the X-H group, is found to increase from S to Te. Thus, the type and extent of the interaction between the TeH group and an unsaturated or cyclopropyl moiety are clarified while the first comparison of interactions between the nonradioactive unsaturated chalcogen derivatives is performed.

Isoselenocyanates versus Isothiocyanates and Isocyanates

“…MHz) δ 4.18 (dt, 1H, J HH = 4.9 Hz, 4 J HH = 1.8 Hz, CH 2 -N), 5.32 (dt, 1H, J HHtrans = 15.0 Hz, J HH = 1.8 Hz, HCH=C), 5.41 (dt, 1H, 3 J HHcis = 10.1 Hz, 4 J HH = 1.8 Hz, HCH=C), 5.82 (ddt, 1H, 3 J HHtrans = 15.0 Hz, 3 J HHcis = 10.1 Hz, 3 J HH = 4.9 Hz, CH). 13 C NMR (CDCl 3 , 100 MHz) δ 47.5 (t, 1 J CH = 155.3 Hz, CH 2 ), 118.5 (t, 1 J CH = 158.4 Hz, CH 2 =C), 124.8 (s, NCSe), 129.1 (d, 1 J CH = 160.6 Hz, CH 2 =CH). A few percent of two minor impurities were observed in the PE and NMR spectra, the allyl selenocyanide coming from a [3,3]-sigmatropic rearrangement 7,8 and the allyl isocyanide coming from the departure of the selenium atom.…”

“…1 H NMR (CDCl 3 , 400 MHz) δ 0.89 (m, 2H, c-CH 2 ), 0.99 (m, 2H, c-CH 2 ), 2.93 (dddd, 1H, 3 J HH = 3 J HH = 7.3 Hz, 3 J HH = 3 J HH = 3.7 Hz, CH). 13…”

Oxygen, sulfur, selenium, tellurium and polonium

“…A number of functionalised tellurols (48) have been prepared and studied using PES and theoretical calculations, and compared to related Group 16 analogues. 74 The isolation of a kinetically stable unsymmetric telluride, { i PrC(QO)CH 2 }MesTe, was reported. 75 Reaction of Te with 2,3-dichloro-1-propene in hydrazine hydrate-KOH yields allene in 78% yield, with complete recovery of the tellurium.…”

A microwave spectroscopic and quantum chemical study of propa-1,2-dienyl selenocyanate (H2CCHSeCN) and cyclopropyl selenocyanate (C3H5SeCN)

“…4 The synperiplanar rotamer of this compound is more stable by 4.5(4) kJ mol À1 . 4 Recently, several new selenocyanates have been synthesized [5][6][7][8] and this has made it possible to investigate their physical properties. The syntheses and photoelectron spectra of several allenyl selenocyanates, including the two title compounds H 2 CQCQCHSeCN 7 and cyclopropylselenocyanate (C 3 H 5 SeCN), 8 have already been reported together with quantum chemical calculations.…”

“…4 Recently, several new selenocyanates have been synthesized [5][6][7][8] and this has made it possible to investigate their physical properties. The syntheses and photoelectron spectra of several allenyl selenocyanates, including the two title compounds H 2 CQCQCHSeCN 7 and cyclopropylselenocyanate (C 3 H 5 SeCN), 8 have already been reported together with quantum chemical calculations. 7,8 In H 2 CQCQCHSeCN, the selenocyanate group is attached to an allenyl group, whereas the selenocyanate group is attached to a cyclopropyl ring in C 3 H 5 SeCN.…”