نتایج جستجو برای: giao

تعداد نتایج: 460  

Journal: :SCIENTIFIC JOURNAL OF TAN TRAO UNIVERSITY 2021

Journal: :Dalton transactions 2014
Athanassios C Tsipis Ioannis N Karapetsas

The GIAO-PBE0/SARC-ZORA(Pt)∪6-31+G(d)(E) (E = main group element) computational protocol without including relativistic and spin-orbit effects is offered here for the accurate prediction of the (195)Pt NMR chemical shifts of a series of cis-(amine)2PtX2 (X = Cl, Br, I) anticancer agents (in total 42 complexes) and cis-diacetylbis(amine)platinum(II) complexes (in total 12) in solutions employing...

Journal: :Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2015
Tao Wang Xueliang Wang

The title compounds, rabdosinate and rabdosin B, were isolated from the leaves of Isodon japonica, and characterized by IR-NMR spectroscopy. The molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO-13C) chemical shift values of the title compounds have been calculated by using DFT/B3LYP method with 6-311++G(d,p) basis set. In addition, obtained results were relat...

Journal: :Journal of Computational Chemistry 2000
Redouan El-Bergmi José A. Dobado Jimez Dolores Portal José Molina Molina

Density Functional Theory (DFT) calculations at the B3LYP/6-31+G∗ level have been performed on 5-thiabicyclo[2.1.1]hex-2-ene S-oxide derivatives. The geometrical and electronic properties of the compounds have been analyzed in order to explain the favored stability of the exo configuration. Isodesmic reactions at the Gaussian-G2 theory yielded the exo conformer as the most stable one. Moreover,...

Journal: :Molecules 2008
Iwona Kowalczyk

1,1-Dimethyl-3-oxo-1,4-diazepan-1-ium chloride (1) and 1,1-dimethyl-1-carboxymethyl-3-aminopropyl ammonium hydrochloride (2) have been obtained by the reactions of 1,1-dimethyl-1,3-propylenediamine with ethyl chloroacetate and chloroacetic acid, respectively. The products have been characterized by FTIR, Raman and NMR spectroscopy. B3LYP calculations have also been carried out. The screening co...

Journal: :Physical chemistry chemical physics : PCCP 2011
Boris Maryasin Hendrik Zipse

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...

2014
Carla I Nieto Pilar Cabildo M Ángeles García Rosa M Claramunt Ibon Alkorta José Elguero

This paper reports the (1)H, (13)C and (15)N NMR experimental study of five benzimidazoles in solution and in the solid state ((13)C and (15)N CPMAS NMR) as well as the theoretically calculated (GIAO/DFT) chemical shifts. We have assigned unambiguously the "tautomeric positions" (C3a/C7a, C4/C7 and C5/C6) of NH-benzimidazoles that, in some solvents and in the solid state, appear different (bloc...

Journal: :Molecules 2017
Diana García-Pérez Concepción López Rosa M Claramunt Ibon Alkorta José Elguero

In this paper, we report the anisochrony of the fluorine atoms of a CHF₂ group when linked to a pyrazole ring. The pyrazole is part of (4S,7R)-7,8,8-trimethyl-4,5,6,7-tetrahydro-4,7-methano-2H-indazole also known as (4S,7R)-campho[2,3-c]pyrazole, which has two stereogenic centers. Gauge-Independent Atomic Orbital (GIAO)/Becke, 3-parameter, Lee-Yang-Parr (B3LYP)/6-311++G(d,f) calculated 19F chem...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2002
Golam Rasul G K Surya Prakash George A Olah

The boronium-carbonium ion continuum was extended to include hypercoordinated onium-carbonium dications and the isoelectronic onium-boronium cation analogs. Structures and (13)C and (11)B NMR chemical shifts of the onium-carbonium dications and the corresponding isoelectronic and isostructural onium-boronium cations were calculated with the ab initio/GIAO-MP2 method. The data show a good linear...

2011
Boris Maryasin Hendrik Zipse

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...

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