ChemInform Abstract: Chiral Selenium and Tellurium Compounds: Synthesis and Properties (70 Literaturangaben).

Excitation and Circular Dichroism Spectra of (+)-(S,S)-bis(2-Methylbutyl)chalcogenides

“…Figure 3 shows individual CD spectra calculated for each conformation of (+)-( S , S )-bis(2-methylbutyl)sulfide ( 1 ), together with the experimental spectrum [ 28 ]. The CD spectra for the most stable conformation (a) obviously disagree with the experimental one, and the other conformations (b)–(f) also do not provide reproduction of the experimental results.…”

“…Figure 5 shows the calculated excitation and CD spectra of (+)-( S , S )-bis(2-methylbutyl)selenide ( 2 ) together with the experimental spectra [ 28 ]. The calculated spectra were obtained by Boltzmann averaging of the conformations (a)–(f) for ( 2 ) at 298 K. Like compound 1 , the individual CD spectra for each conformation disagree with the experimental one, whereas the averaged spectrum were in agreement.…”

“…CD spectra for dichalcogenide compounds (ditellurides, diselenides, disulfides, and dioxides in some studies) have been studied experimentally [ 27 , 28 ] and theoretically [ 5 , 16 , 18 , 24 ] because of interest in the roles and stereochemistry of the chalcogen-chalcogen bonds in polypeptides, proteins, and other biochemical systems. We also carried out the SAC/SAC-CI calculations of CD spectra for twelve dichalcogenide molecules [ 24 ].…”

“…The calculations of CD spectra for monochalcogenide compounds have not been reported as frequently, in spite of the fact that the experimental excitation and CD spectra were observed by Laur for cyclic and acyclic sulfides, selenides, and tellurides [ 28 , 29 ]. In the preceding studies, the band assignments were performed only for the bands in the UV spectra of sulfide and selenide molecules based on the semi-empirical calculations and the analogy with the sulfides, respectively.…”

“…On the other hand, for straight-chain monochalcogen molecules, the calculations of the CD spectra have not been reported as far as we know. The experimental excitation and CD spectra were observed by Laur for bis(2-methylbutyl)-chalcogenides, Ch[CH 2 CH(CH 3 )C 2 H 5 ] 2 (Ch = S, Se, Te) [ 28 , 29 ], but the band assignments were unconfirmed. One of the difficulties in the CD calculations for these systems is due to the flexibility of the molecule, namely, taking into consideration many conformation variations.…”