Molecular modeling spectroscopy

Nuclear magnetic resonance (NMR) spectroscopy is a valuable technique for obtaining chemical information. This is because the spectra are very sensitive to changes in the molecular structure. This same sensitivity makes NMR a difficult case for molecular modeling. 

These ideas have been extended using new analytical techniques, in particular molecular modeling and soHd-state nuclear magnetic resonance (nmr) spectroscopy. 

Cyclopentane, angle strain in. 116 conformation of, 116 molecular model of, 116 strain energy of, 114 torsional strain in, 116 Cyclopentanone. TR spectroscopy of, 731... 

Thevand A et al. (2004) Total assignment and structure in solution of tetrandrine by NMR spectroscopy and molecular modelling. Spectrochim Acta A Mol Biomol Spectrosc 60(8-9) 1825-1830... 

Abstract Protoberberine alkaloids and related compounds represent an important class of molecules and have attracted recent attention for their various pharmacological activities. This chapter deals with the physicochemical properties of several isoquinoline alkaloids (berberine, palmatine and coralyne) and many of their derivatives under various environmental conditions. The interaction of these compounds with polymorphic DNA structures (B-form, Z-form, H -form, protonated form, triple helical form and quadruplex form) and polymorphic RNA structures (A-form, protonated form, triple helical form and quadruplex form) reported by several research groups, employing various analytical techniques such as spectrophotometry, spectrofluorimetry, circular dichro-ism, NMR spectroscopy, viscometry as well as molecular modelling and thermodynamic analysis to elucidate their mode and mechanism of action for structure-activity relationships, are also presented. 

Pietrzyk, P., Gil, B. and Sojka, Z. (2007) Combining computational and in situ spectroscopies joint with molecular modeling for determination of reaction intermediates of deNOx process -CuZSM-5 catalyst case study, Catal. Today. doi 10.1016/j.cattod.2006.09.033. 

It has been observed that cobalt may undergo large-scale reconstruction under a synthesis gas environment.27 Reconstruction is a thermodynamically driven process that results in the stabilization of less reactive surfaces. Recent molecular modeling calculations have shown that atomic carbon can induce the clock reconstruction of an fee cobalt (100) surface.28 It has also been postulated and shown with in situ x-ray adsorption spectroscopy (XAS) on cobalt supported on carbon nanofibers that small particles (<6 nm) undergo a reconstruction during FTS that can result in decreased activity.29... 

In a correction to previous work, the cyclization of 4-ureidobutyric acids with thionyl chloride has been shown (by NMR spectroscopy) to result in pyrrolidinone carboxamide derivatives and not aryl perhydro-l,3-diazepine-2,4-diones <00JHC111>. Optimization of the geometry of l-(o-nitrophenyl)-2-phenyl-l//-4,5,6,7-tetrahydro-l,3-diazepine has been undertaken using computer-based molecular modelling, and correlations made with theoretical and experimental UV spectra . 

Keywords Mangrove barks, molecular modeling, phase transformation, rast, spectroscopy, tannin, transformation. 

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