RESUMO
The regioselective opening of the F ring of 22-oxo-23-spiroketals 7a-d using TiCl4 in acetic anhydride yielded the novel furostanols 11a-d along with cholestanic derivatives 8a-d with pyranone E ring. The structures of the new derivatives thus obtained were established using one- (DEPT) and two-dimensional 1H, 13C NMR experiments (COSY, HSQC, HMBC, NOESY). The 22α-hydroxyl orientation in compounds 11a-d was proposed by comparison of the 13C chemical shifts with those of other aglycone members of this family, and confirmed by combined NOESY and X-ray diffraction analysis of compound 11a.
Assuntos
Furanos/química , Glicosídeos/química , Sapogeninas/síntese química , Compostos de Espiro/química , Esteróis/química , Titânio/química , Catálise , Modelos Moleculares , Conformação Molecular , Sapogeninas/químicaRESUMO
In this work, microwave synthesis, chemical, optical and electrochemical characterization of three small organic molecules, TPA-TPD, TPA-PT-TPD and TPA-TT-TPD with donor-acceptor structure and their use in organic photovoltaic cells are reported. For the synthesis, 5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione was used as electron withdrawing fragment while the triphenylamine was used as electron donating fragment. Molecular electronic geometry and electronic distribution density were established by density functional theory (DFT) calculations and confirmed by optical and chemical characterization. These molecules were employed as electron-donors in the active layer for manufacturing bulk heterojunction organic solar cells, where [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) was used as electron-acceptor. As cathode, Field's metal (FM), an eutectic alloy (Bi/In/Sn: 32.5%, 51%, and 16.5%, respectively) with a melting point above 62 °C, was easily deposited by drop casting under vacuum-free process and at air atmosphere. Prepared devices based on TPA-TPD:PC71BM (1:4 w/w ratio) presented a large VOC = 0.97 V, with JSC = 7.9 mA/cm², a FF = 0.34, then, a power conversion efficiency (PCE) of 2.6%.
Assuntos
Ligas/química , Fontes de Energia Elétrica , Pirróis/química , Energia Solar , Eletricidade , Transporte de Elétrons , Micro-Ondas , Modelos Moleculares , Estrutura Molecular , Luz SolarRESUMO
In the title compound, C15H17NO4S2, synthesized by addition of O-ethylxanthic acid potassium salt to a diastereomeric mixture of (4R)-3-(2-chloro-propano-yl)-4-phenyl-oxazolidin-2-one, the oxazolidinone ring has a twist conformation on the C-C bond. The phenyl ring is inclined to the mean plane of the oxazolidinone ring by 76.4â (3)°. In the chain the methine H atom is involved in a C-Hâ¯S and a C-Hâ¯O intra-molecular inter-action. In the crystal, mol-ecules are linked by C-Hâ¯π inter-actions, forming chains along [001]. The S configuration at the C atom to which the xanthate group is attached was determined by comparison to the known R configuration of the C atom to which the phenyl group is attached.