155791-98-3Relevant academic research and scientific papers
Synthesis of organyltellanyl(IV) trihalides [2-(Me2NCH2)C6H4TeX3] (X?=?Cl, Br, I) and their rare zwitterionic derivatives containing organyltellanyl(II) groups
da Silva, Felipe D.,Sim?es, Cláudia A.D.P.,dos Santos, Sailer S.,Lang, Ernesto S.
, p. 66 - 71 (2017)
In this article we describe the synthesis and structural characterization of a series of organyltellanyl(IV) trihalides containing the [2-((dimethylamino)methyl)phenyl] moiety [2-(Me2NCH2)C6H4TeX3] (X?=?Cl, Br, I), and some of its derivatives in the form of rare zwitterionic compounds with organyltellanyl(II) groups. The supramolecular structure of the different organyltellanyl halides presents considerable changes due to the nature of Te?X and X?X secondary interactions. The positive and negative charges of the zwitterionic compounds, the size of the halogens and the repulsion of the lone electron pairs around the tellurium atom were also evaluated. All compounds were characterized by single crystal X-ray diffraction, vibrational spectroscopy (FT-IR and Raman) and NMR (1H and125Te) spectroscopy and elemental analysis.
Catalytic reduction of graphene oxide nanosheets by glutathione peroxidase mimetics reveals a new structural motif in graphene oxide
Vernekar, Amit A.,Mugesh, Govindasamy
supporting information, p. 16699 - 16706 (2014/01/06)
A catalytic reduction of graphene oxide (GO) by glutathione peroxidase (GPx) mimics is reported. This study reveals that GO contains peroxide functionalities, in addition to the epoxy, hydroxyl and carboxylic acid groups that have been identified earlier. It also is shown that GO acts as a peroxide substrate in the GPx-like catalytic activity of organoselenium/tellurium compounds. The reaction of tellurol, generated from the corresponding ditelluride, reduces GO through the glutathione (GSH)-mediated cleavage of the peroxide linkage. The mechanism of GO reduction by the tellurol in the presence of GSH involves the formation of a tellurenic acid and tellurenyl sulfide intermediates. Interestingly, the GPx mimics also catalyze the decarboxylation of the carboxylic acid functionality in GO at ambient conditions. Whereas the selenium/tellurium-mediated catalytic reduction/decarboxylation of GO may find applications in bioremediation processes, this study suggests that the modification of GO by biologically relevant compounds such as redox proteins must be taken into account when using GO for biomedical applications because such modifications can alter the fundamental properties of GO.
Thiol peroxidase activity of diaryl ditellurides as determined by a 1H NMR method
Engman, Lars,Stern, David,Cotgreave, Ian A.,Andersson, Carl M.
, p. 9737 - 9743 (2007/10/02)
A 1H NMR method was developed for the assessment of the glutathione peroxidase-like activity of synthetic compounds. In this assay, thiols (N-acetylcysteine, tert-butyl mercaptan and 1-octyl mercaptan) were oxidized to the corresponding disulfides in CD3OD or CD3OD/D2O in the presence of hydrogen peroxide and the catalyst to be evaluated. The time required to reduce the thiol concentration with 50%, t50, was determined as a measure of the thiol peroxidase activity of the catalyst. Several diaryl ditellurides were efficient catalysts when present in low concentrations (0.3 mol %), whereas compounds with well-documented glutathione peroxidase-like activity in other assays were inactive (Ebselen, diaryl diselenides). The glutathione peroxidase-like activity of diaryl ditellurides was also assessed by using the classical coupled reductase assay. A mechanistic study showed that diaryl ditellurides, in the presence of hydrogen peroxide and a thiol, were rapidly converted to tellurosulfides. These species were stable enough to be isolated in some cases. The tellurosulfides reacted very slowly with added thiol, but in the presence of thiol/hydrogen peroxide the thiol was rapidly converted to its corresponding disulfide. On the basis of these observations, a mechanism involving a tellurinic acid thiol ester was proposed for the thiol peroxidase reaction of ditellurides. In contrast to tellurosulfides, selenosulfides, obtained either from diphenyl diselenide/hydrogen peroxide/1-octyl mercaptan or from Ebselen and 1-octyl mercaptan, were found to react very slowly with thiols in the presence of hydrogen peroxide.
