tailieunhanh - Ebook Organic structure determination using 2-D NMR spectroscopy: Part 2

(BQ) Part 2 book "Organic structure determination using 2-D NMR spectroscopy" has contents: Through-Space efects: The nuclear overhauser efect, molecular dynamics, strategies for assigning resonance to atoms within a molecule, strategies for elucidating unknown molecular structures, simple assignment problems,.and other contents. | Chapter 8 Molecular Dynamics Molecular dynamics covering a wide range of time scales produce an array of effects in NMR spectroscopy. In large molecules, motion of different segments of a molecule may yield measurably distinct relaxation times, thus allowing us to differentiate between signals from different parts of a molecule. Conformational rearrangements can change the chemical shifts of NMR-active nuclei and the J-couplings observed between various spins. Rapid molecular motions average shifts and/or J-couplings, whereas slower motions may make discovering the underlying mechanistic motions difficult. In many cases, molecular motion and chemical exchange may give broad NMR lines devoid of coupling information. Fortunately, most modern NMR spectrometers include variable temperature (V T ) controlling equipment that allows the sample temperature to cover a wide range. Varying the sample temperature may allow us to observe signals that would be poorly suited to supplying desired information at ambient temperature. Probes containing pulsed field gradient (PFG) coils, however, can often only tolerate a more limited range of temperatures compared to their PFG-coil-lacking counterparts; this reduced operating temperature range is attributable to the limitations associated with the materials used to construct these technologically sophisticated probes and the need to minimize thermal stress. Typical temperature ranges for a normal liquids NMR probe are from about Ϫ100°C to ϩ120°C, and PFG probes may only tolerate temperatures in the range of Ϫ20°C to ϩ80°C. Individual vendors list the temperature range recommended for each of their probes. For the purposes of structural elucidation and resonance assignment, a cursory understanding of molecular dynamics and relaxation is 151 152 CHAPTER 8 Molecular Dynamics useful, but often not essential. Recognizing when a particular resonance is broadened as a result of exchange and knowing what step or steps we might take to .

• Hoá học
• Organic structure determination
• Organic structure
• Unknown molecular structures
• Simple assignment problems
• The nuclear overhauser efect
• Molecular dynamics
• Nuclear engineering and technology
• Point defects and grain boundary effects on tensile strength
• 3C SiC studied by molecular dynamics simulations
• Molecular dynamics simulations
• Symmetric tilt grain boundaries
• Molecular dynamics simulation
• Dynamical properties
• The microstructural transformation
• Microstructural transformation
• Mechanism diffusion
• Sodium silicate
• Cu/Ta nanofilms
• Hirth dislocations
• Thompson tetrahedron
• Tensile strength
• Monocrystalline gold
• Tensile properties
• Monocrystalline gold film
• Si substrate
• Incident energy
• Growth mode
• BMC Chemistry
• Homology modelling
• Molecular docking
• Antifungal activities
• Inhibition mechanism
• Journal of Chemistry
• Three dimensional quantitative structure activity relationship
• 1 2 3 triazole
• Acetylcholinesterase inhibitory activity
• Alzheimer’s disease
• Advanced Molecular
• Dynamics Simulations
• Numerical Integration
• Techniques Based
• Systematic Approach
• Nanoparticle translocation
• Ion current
• Coulter counter principle
• Atomistic molecular dynamics
• Carbohydrate polymers
• Polysaccharide structure dynamics
• Phase separation
• Xylan oligomers
• Atomistic molecular dynamics simulation
• BMC Bioinformatics
• Fusion protein
• Molecular modeling
• Malaria morbidity
• Replica exchange molecular dynamics simulation
• Generalized Born implicit solvent
• Tumor cells
• Anti inflammatory
• β lactamases inhibitor
• Antibiotic resistance
• BMC Genomics
• WRKY transcription factors
• DNA binding proteins
• Sodium channel
• Program HyperChem
• Drug–receptor interaction
• Computational chemistry
• Fundamental principles
• Molecular mechanics
• Density functional theory
• Molecular Systems
• Reaction Dynamics
• Nuclear Dynamics
• Molecular Photochemistry
• Adiabatic Approximation
• Permutational Symmetry
• Communications in Physics
• Influence of disulfide bridge
• The structural stability of human neuroglobin
• Latest data entry
• Polyamorphism and two state model
• Liquid Geo2 under compression
• Visualization of molecular dynamics data
• Low density and high density
• High density phase region
• Vietnam Journal of Mechanics
• Molecular dynamics extended finite element method
• Dynamic crack propagation
• Two dimensional computation
• The coupled model
• The energy transfer
• Two dimensional Fe C
• Square lattice struture
• Phase transition
• Thermodynamic properties
• MD simulation
• Silico characterization
• Expression analysis
• Class I chitinases
• Aloe barbadensis
• N acetylneuraminic acid analogues
• H5N1 influenza a virus
• Haemagglutinin and molecular
• Dynamics simulation
• Nano spaced dimers
• Structure of the Aβ42 tetramer
• Physicochemical properties of the Aβ42 tetramer
• Multiscale molecular dynamics simulations
• The proposed all atom structures
• Higher order oligomers
• Mathematics physics
• Pressure effect
• The structural properties