62671-38-9Relevant articles and documents
Metallo-β-lactamase-catalyzed hydrolysis of cephalosporins: Some mechanistic insights into the effect of heterocyclic thiones on enzyme activity
Tamilselvi,Mugesh, Govindasamy
, p. 749 - 756 (2011)
The hydrolysis of β-lactam antibiotics using zinc-containing metallo-β-lactamases (mβl) is one of the major bacterial defense systems. These enzymes can catalyze the hydrolysis of a variety of antibiotics including the latest generation of cephalosporins, cephamycins, and imipenem. It is shown in this paper that the cephalosporins having heterocyclic-SR side chains are less prone to mβl-mediated hydrolysis than the antibiotics that do not have such side chains. This is partly due to the inhibition of enzyme activity by the thione moieties eliminated during hydrolysis. When the enzymatic hydrolysis of oxacillin was carried out in the presence of heterocyclic thiones such as MTT, MDT, DMETT, and MMA, the catalytic activity of the enzyme was inhibited significantly by these compounds. Although the heterocyclic-SR moieties eliminated from the β-lactams upon hydrolysis undergo a rapid tautomerism between thione and thiol forms, these compounds act as thiolate ligands toward zinc(II) ions. The structural characterization of two model tetranuclear zinc(II) thiolate complexes indicates that the-SR side chains eliminated from the antibiotics may interact with the zinc(II) metal center of mβl through their sulfur atoms.
Efficient dye-sensitized photovoltaic wires based on an organic redox electrolyte
Pan, Shaowu,Yang, Zhibin,Li, Houpu,Qiu, Longbin,Sun, Hao,Peng, Huisheng
, p. 10622 - 10625 (2013)
An organic thiolate/disulfide redox couple with low absorption in the visible region was developed for use in fabricating novel dye-sensitized photovoltaic wires with an aligned carbon nanotube (CNT) fiber as the counter electrode. These flexible wire devices achieved a maximal energy conversion efficiency of 7.33%, much higher than the value of 5.97% for the conventional I-/I3- redox couple. In addition, the aligned CNT fiber also greatly outperforms the conventional Pt counter electrode with a maximal efficiency of 2.06% based on the thiolate/disulfide redox couple.
Improved efficiency of CdS quantum dot sensitized solar cell with an organic redox couple and a polymer counter electrode
Shu, Ting,Li, Xiong,Ku, Zhi-Liang,Wang, Shi,Wu, Shi,Jin, Xiao-Hong,Hu, Chun-Di
, p. 700 - 704 (2014/12/11)
Quantum dot sensitized solar cells (QDSSCs) based on an organic thiolate/disulfide redox couple (C7H5N4S-/C14H10N8S2or C2H3N4S-/C4H6N8S2) and a polymer counter electrode [poly (3, 4-ethylenedioxythiophene), PEDOT] were fabricated and their photovoltaic performance were investigated. In CdS QDSSC, the organic C7H5N4S-/C14H10N8S2electrolyte shows better performance than the polysulfide electrolyte, and the PEDOT counter electrode exhibits higher efficiency than that of the Pt counter electrode and the CoS counter electrode. An efficiency of 1.53% was achieved in this QDSSC. The influences of the morphology and the deposition charge of the PEDOT counter electrodes on the cell performance were also studied. Furthermore, it was found that the C7H5N4S-/C14H10N8S2redox couple outperformed the C2H3N4S-/C4H6N8S2redox couple due to reduced electron recombination.
Redox chemistry between graphene oxide and mercaptan
Fan, Deqin,Zhang, Chao,He, Junpo,Hua, Rong,Zhang, Yang,Yang, Yuliang
experimental part, p. 18564 - 18571 (2012/10/08)
We report here redox reactions between graphene oxide (GO) and mercaptans, which reduces GO to reduced graphene oxide (RGO) and oxidizes mercaptans into disulfides. The reduction processes of GO using various mercaptans as the reducing agents are investigated through XPS, TGA, FT-IR, Raman and EA analysis. The degree of reduction of RGO depends on molecular structure of mercaptans and is controlled by the reaction time. The redox reaction is also employed to oxidize mercaptans into disulfides in medium to high yields under moderate conditions. The mechanism of the redox reaction may involve nucleophilic ring opening of oxirane on GO by alkylthio moiety, followed by addition of another alkylthio group, leaving the resulting disulfide. The reduction of the hydroxy group could be more complex, involving both radical and anionic processes.
