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Vibrational Study (vibrational + study)
Selected AbstractsChemInform Abstract: Structural and Vibrational Study of [Mo7O24]6- and [W7O24]6- .CHEMINFORM, Issue 50 2009Blandine Courcot Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Structural and Vibrational Study of Uranium(III) Molecules by Density Functional Methods.CHEMINFORM, Issue 49 2001Laurent Joubert Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Structural and vibrational study of 2-(2,- furyl)-4,5-1H -dihydroimidazoleJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2009Juan Zinczuk Abstract In this study 2-(2,-furyl)-4,5-1H -dihydroimidazole (1) was prepared and then characterized by infrared, Raman, and multidimensional nuclear magnetic resonance (NMR) spectroscopies. The crystal and molecular structures of 1 were determined by X-ray diffraction methods. The density functional theory (DFT) and second-order Møller,Plesset theory (MP2) with Pople's basis set show that there are two conformers for the title molecule that have been theoretically determined in the gas phase, and that only one of them, conformer I, is present in the solid phase. NMR spectra observed for 1 were successfully compared with the calculated chemical shifts at the B3LYP/6-311++G** level theorized for this conformer. The harmonic vibrational frequencies for the optimized geometry of the latter conformer were calculated at the B3LYP/6-311++G** level in the approximation of the isolated molecule. For a complete assignment of the IR and Raman spectra in the solid phase of 1, DFT calculations were combined with Pulay´s scaled quantum mechanics force field (SQMFF) methodology to fit the theoretical frequency values to the experimental ones. Copyright © 2009 John Wiley & Sons, Ltd. [source] Characteristic Raman and IR bands of 3,3,-benzylidenebis(4-hydroxycoumarin) and its La(III), Ce(III) and Nd(III) complexesJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2006N. Trendafilova Abstract In the present paper we perform a detailed vibrational study of 3,3,-benzylidenebis(4-hydroxycoumarin) (phenyldicoumarol, PhDC) based on both experimental (IR and Raman) and calculated (DFT) vibrational spectra. To help the assignment of the PhDC vibrational modes, the vibrational spectrum of the monomeric building block, 4-hydroxycoumarin (4-HC), was also considered. The PhDC and 4-HC vibrational spectra were calculated and assigned at the B3LYP/6-31G* optimized geometries. The vibrational spectra of the La(III), Ce(III) and Nd(III) complexes with PhDC are discussed in a comparative study with the vibrational spectrum of the free PhDC ligand. The ,(CCH)ip, ,(CCH)op and ,(COH)ip vibrational modes as well as in-plane phenyl- and in-plane coumarin rings deformations were observed as strong bands in the Raman spectrum of PhDC and can be considered as a characteristic for the compound. Because of the very low IR intensity, these modes were not detected in the IR spectrum. Informative ligand vibrational modes were selected and their behaviors in the Ln(III) complexes were further studied to suggest the type of the PhDC binding mode to Ln(III) ions. Copyright © 2006 John Wiley & Sons, Ltd. [source] Surface adsorption of 4,4,-dithiodipyridine and 2,2,-dithiodipyridine on silver nanoparticlesJOURNAL OF RAMAN SPECTROSCOPY, Issue 5 2003Helena I. S. Nogueira Abstract A detailed vibrational study on the isomers 2,2,-dithiodipyridine and 4,4,-dithiodipyridine was carried out. These organic ligands are of great interest as possible linkers in the fabrication of nanostructures, and therefore a study on the adsorption modes of both ligands at silver surfaces is presented. Orientational information on the 2,2,-dithiodipyridine and 4,4,-dithiodipyridine molecules adsorbed on silver colloids was collected based on the SERS spectra and supported by ab initio calculations. There is evidence that both organic ligands adsorb on the silver surface through the sulfur atoms, with the aromatic rings in a tilted position. Copyright © 2003 John Wiley & Sons, Ltd. [source] Synthesis of the First Chiral Bidendate Bis(trifluoromethyl)phosphane Ligand through Stabilization of the Bis(trifluoromethyl)phosphanide Anion in the Presence of AcetoneCHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2006Berthold Hoge Priv.-Doz. Abstract Lewis acid/Lewis base adduct formation of the P(CF3)2, ion and acetone leads to a reduced negative hyperconjugation and, therefore, limits the CF bond activation. The resulting increased thermal stability of the P(CF3)2, ion in the presence of acetone allows selective substitutions and enables the synthesis of the first example of a chiral, bidentate bis(trifluoromethyl)phosphane ligand: a DIOP derivative, [(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis(diphenylphosphane), in which the phenyl groups at the phosphorus atoms are replaced by strong electron-withdrawing trifluoromethyl groups. The resulting high electron-acceptor strength of the synthesized bidentate (CF3)2P ligand is demonstrated by a structural and vibrational study of the corresponding tetracarbonyl,molybdenum complex. The stabilization of the P(CF3)2, ion in the presence of acetone is based on the formation of a dynamic Lewis acid/Lewis base couple, (CF3)2PC(CH3)2O,. Although there is no spectroscopic evidence for the formation of the formulated alcoholate ion, the intermediate formation of (CF3)2PC(CH3)2O, could be proved through the reaction with (CF3)2PP(CF3)2, which yields the novel phosphane,phosphinite ligand (CF3)2PC(CH3)2OP(CF3)2. This ligand readily forms square-planar Pt(II) complexes upon treatment with solid PtCl2. [source] | ||||||||||