نتایج جستجو برای: cpmas nmr
تعداد نتایج: 58833 فیلتر نتایج به سال:
195pt and 1h nmr has been used to show that addition of chlorine and bromine to [pt(cn)4]2_ in presence of perchloric acid in water results in cyanide and water scrambling with formation of eleven complexes of the type [pt(cn)4-ncl(h2o)n+1](n-1)+ (n=0, 1, 2, 3, 4). addition of nbu4oh to this solution gives (nbu4)2[pt(cn)4cl(oh)]. nmr measurements in acetone also show cyanide and hydroxyl group ...
the dopamine has been studied theoretically at the b3lyp/6-31g* level were performed in gasphase. we calculated physical parameters like atomic charges, energy (=>), asymmetry parameter(?), chemical shift @iso, dipole moment and isotropic nmr determinant and in this work we usedgaussian 03 at nmr and calculation by using b3lyp methods with 6-31g* basis set.
the methamphetamine has been studied theoretically at the mp2 [1]/6-31g[2] level in gas phase.methamphetamine has been investigated via nmr, frequencies calculation and nbo analysis. thestructure of methamphetamine was designed primarily using of chem. bio draw and it geometry hasbeen optimized at the mp2/6-31g computational level. the present work consists the study of themethamphetamine repor...
Contaminant sorption, an important process that may limit bioavailability, hinder remediation, encourage environmental persistence, and control mobility in the environment, has been the focus of numerous studies. Despite these efforts, the fundamental understanding of sorptive processes in soil and sedimentary environments has not been resolved. For instance, many have suggested that contaminan...
As part of investigations into the effects of harvesting old-growth forest, we characterized carbon in five organic matter pools in eight forest chronosequences of coastal British Columbia. Each chronosequence comprised stands in four seral stages from regeneration (3-8 yr) to old-growth (>250 yr), with second-growth stands mostly of harvest origin. Stands were located in two biogeoclimatic sub...
Reactions of the aminoiminophenols 2-((2-(dimethylamino)ethylimino)methyl)phenol (HL(1)) or 2-{(3-(dimethylamino)propylimino)methyl}phenol (HL(2)) with nickel(II) chloride, K(2)[PtCl(4)] or copper(II) acetate in alcoholic solution, in the absence or in the presence of sodium azide, afford the corresponding new mononuclear complexes [M(L(1))(X)(H(2)O)(n)] [M = Ni, X = Cl(-), n = 2 (); M = Ni, X ...
Series of polynuclear diorganotin(IV) complexes with di-halogenbenzohydroxamate ligands (substituents=2,4-Cl(2), 2,4-F(2), 3,4-F(2), 2,5-F(2), 2,6-F(2)), formulated as the polymeric [R(2)SnL](n)a (1:1) and the tetranuclear [R(4)Sn(2)(HL)(2)(L)](2)b (2:3) (HL=arylhydroxamate), were prepared and characterized by FT-IR, (1)H, (13)C, (119)Sn NMR spectroscopies, elemental analyses and melting point ...
The majority of solids NMR experiments today are driven by biological applications in rigid macromolecules, where even the most advanced liquids methods are limited by the spectral resolution they can achieve. Obtaining detailed structural information from NMR of solid samples is often more technically demanding than for liquids because of the absence of molecular tumbling in solids to average ...
The relative stability of -helix and -sheet secondary structure in the solid state was investigated using poly(L-alanine) (PLA) as a model system. Protein folding and stability has been well studied in solution, but little is known about solid-state environments, such as the core of a folded protein, where peptide packing interactions are the dominant factor in determining structural stability....
BACKGROUND Several papers described the structure of curcumin and some other derivatives in solid and in solution. In the crystal structure of curcumin, the enol H atom is located symmetrically between both oxygen atoms of the enolone fragment with an O···O distance of 2.455 Å, which is characteristic for symmetrical H-bonds. In the solution, the geometry of the enolone fragment is attributed t...
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