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Data-mining the diaryl(thio)urea conformational landscape: Understanding the contrasting behavior of ureas and thioureas with quantum chemistry
داده کاوی چشم انداز تطابقی ادرار (تیو) اوره: درک رفتار متضاد اوره و تیوره با شیمی کوانتومی-2019 The conformations adopted by urea and thiourea functional groups influence catalysis and binding. We
combine data-mining with quantum chemical calculations to understand the differences in conformational
behavior for these two important structural motifs. We developed a Python tool to automate the
compilation of X-ray structural information and perform conformational clustering and visualization,
based on SMILES input. While diarylureas have an overwhelming preference for the anti,anti-conformer,
diarylthioureas adopt a mixture of anti,anti- and anti,syn-conformers. Computations show the anti,antithiourea
conformer is destabilized by out-of-plane rotations which avoid a steric clash with the sulfur
atom. These conformational preferences were studied computationally under a variety of conditions, and
apart from in the gas-phase, a preference for anti,anti-ureas was found. Consistent with experiments, this
preference increases in more polar environments. Quantitative predicted ratios are sensitive to the
computational treatment of solvation effects, with COSMO-RS giving more realistic amounts of the
anti,anti-conformer in THF and DMSO. Keywords: Conformational analysis | Density functional theory | Urea | Thiourea | Organocatalyst | X-ray structure | Solvation | Data-mining |
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