Sixty R3SiX/solvent (S) and R2HSiX/S systems with R ) methyl, ethyl, butyl and S ) methylene chloride, DMPU, DMSO, sulfolane, HMPA, acetonitrile, pyridine, N-methylimidazole, and triethylamine were investigated with the help of NMR spectroscopy for different concentration ratios of R3SiX/S and R2HSiX/S as well as different temperatures. With the help of measured δ29Si and δ13C chemical shifts a...

Preceding NMR experiments show that the conformation of tandem GA base pairs, an important recurrent non-canonical building block in RNA duplexes, is context dependent. The GA base pairs adopt "sheared" N3(G)-N6(A), N2(G)-N7(A) geometry in the r(CGAG)(2) and r(iGGAiC)(2) contexts while switching to "imino" N1(G)-N1(A), O6(G)-N6(A) geometry in the r(GGAC)(2) and r(iCGAiG)(2) contexts (iC and iG ...

Selected theoretical methods, basis sets and solvation models have been tested in their ability to predict (31)P NMR chemical shifts of large phosphorous-containing molecular systems in solution. The most efficient strategy was found to involve NMR shift calculations at the GIAO-MPW1K/6-311++G(2d,2p)//MPW1K/6-31G(d) level in combination with a dual solvation model including the explicit conside...

The role of various factors (structure, solvent, and relativistic treatment) was evaluated for square-planar 4d and 5d transition-metal complexes. The DFT method for calculating the structures was calibrated using a cluster approach and compared to X-ray geometries, with the PBE0 functional (def2-TZVPP basis set) providing the best results, followed closely by the hybrid TPSSH and the MN12SX fu...

Selected theoretical methods, basis sets and solvation models have been tested in their ability to predict P NMR chemical shifts of large phosphorous-containing molecular systems in solution. The most efficient strategy was found to involve NMR shift calculations at the GIAO-MPW1K/ 6-311++G(2d,2p)//MPW1K/6-31G(d) level in combination with a dual solvation model including the explicit considerat...

The change in (1)H NMR chemical shifts upon hydrogen bonding was investigated using both experimental and theoretical methods. The (1)H NMR spectra of a number of phenols were recorded in CDCl(3) and DMSO solvents. For phenol, 2- and 4-cyanophenol and 2-nitrophenol the OH chemical shifts were measured as a function of concentration in CDCl(3). The plots were all linear with concentration, the g...

AB-alternating copolymers based on vinyl phenol and n-alkyl (C12 or C18) maleimide self-assemble into nanoparticles via ouzo effect. Size structure are determined by copolymer lipo/hydrophilicity, solvent/water affinity solvent diffusivity.

the synthesis and properties of new monoazo dyes derived from the diazonium salts of paminobenzoic acid, 3-trifluoromethyl aniline , 4-trifluoromethyl aniline are considered .theprepared compounds were characterized by uv-visible , ft-ir and h nmr spectroscopictechniques . the effect of varying solvent upon the absorption ability of p-amino benzoic acidcoupled with 4,4 —diethyl aniline , anilin...