Organic structure determination using 2-D NMR spectroscopy: a problem-based approach

This book contains 30-40 quality 2D NMR data sets following an introductory section describing the methodology employed. Many other books describe the methods used, but none offer a large number of problems. Instructors at universities and colleges at the present time are forced to cobble together problems from a wide range of sources. The fragmentary approach to assembling course materials has a negative impact on course continuity and thus adversely impacts student retention. This book will stand as a single source to which instructors and students can go to obtain a comprehensive compendium of NMR problems of varying difficulty. Presents strategies for assigning resonances to known structures and for deducing structures of unknown organic molecules based on their NMR spectra . Contains 20 known and 20 unknown structure determination problems . Features a supporting website from which instructors can download the structures of the unknowns in selected chapters, digital versions of all figures, and raw data sets for processing. INDICE: PART I: Background and Methods Chapter 1: Introduction What is NMR? Consequences of Nuclear Spin Application of a Magnetic Field to a Single Nuclear Spin Application of a Magnetic Field to an Ensemble of Nuclear Spins Tipping the Net Magnetization Vector from Equilibrium Signal Detection The Chemical Shift The 1-D NMR Spectrum The 2-D NMR Spectrum Information Content Available Using NMR Chapter 2: Instrumental Considerations Sample Preparation Locking Shimming Temperature Regulation Modern NMR Instrument Architecture Pulse Calibration Sample Excitation and the Rotating Frame of Reference Pulse Rolloff Probe Variations Analog Signal Detection Signal Digitization Chapter 3: Data Collection, Processing, and Plotting Setting the Spectral Window Determining the Optimal Wait Between Scans Setting the Acquisition Time How Many Points to Acquire in a 1-D Spectrum Zero Filling and Digital Resolution Setting the Number of Points to Acquire in a 2-D Spectrum Truncation Error and Apodization The Relationship Between T2* and Observed Line Width Resolution Enhancement Forward Linear Prediction Pulse Ringdown and Backward Linear Prediction Phase Correction Baseline Correction Integration Measurement of Chemical Shifts and J-Couplings Data Representation Chapter 4: 1H and 13C Chemical Shifts The Nature ofthe Chemical Shift Aliphatic Hydrocarbons Saturated, Cyclic Hydrocarbons Olefinic Hydrocarbons Acetylenic Hydrocarbons Aromatic Hydrocarbons Heteroatom Effects Chapter 5: Symmetry and Topicity Homotopicity Enantiotopicity Diastereotopicity Chemical Equivalence Magnetic Equivalence Chapter 6: Through-Bond Effects: Spin-Spin (J) Coupling Origin of J-Coupling Skewing of the Intensity of Multiplets Prediction of First-Order Multiplets The Karplus Relationship for Spins Separated by Three Bonds The Karplus Relationship for Spins Separated by Two Bonds Long Range J-Coupling Decoupling Methods One-Dimensional ExperimentsUtilizing J-Couplings Two-Dimensional Experiments Utilizing J-Couplings Chapter 7: Through-Space Effects: the Nuclear Overhauser Effect (NOE) The Dipolar Relaxation Pathway The Energetics of an Isolated Heteronuclear Two-Spin SystemThe Spectral Density Function Decoupling One of the Spins in a Heteronuclear Two-Spin System Rapid Relaxation via the Double Quantum Pathway A One-Dimensional Experiment Utilizing the NOE Two-Dimensional Experiments Utilizing the NOE Chapter 8: Molecular Dynamics Relaxation Rapid Chemical Exchange Slow Chemical Exchange Intermediate Chemical Exchange Two-Dimensional Experiments that Show Exchange Chapter 9: Strategies for Assigning Molecules Prediction of Chemical Shifts Prediction of Integrals and Intensities Prediction of 1H MultipletsGood Bookkeeping Practices Assigning 1H Resonances on the Basis of Chemical Shifts Assigning 1H Resonances on the Basis of Multiplicities Assigning 1H Resonances on the Basis of the gCOSY Spectrum The Best Way to Read a 2-D gCOSY Spectrum Assigning 13C Resonances on the Basis of Chemical Shifts Pairing 1H and 13C Shifts By Using the HSQC/HMQC Spectrum Assignment of Non-Protonated 13C's on the Basis of the HMBC Spectrum Chapter 10: Strategies for Elucidating Unknown Molecular Structures Initial Inspection of the One-Dimensional Spectra Good Accounting Practices Identification of Entry Points Completion of Assignments PART II: Problems Chapter 11 Simple Assignment Problems Chapter 12: Complex Assignment Problems Chapter 13: Simple Unknown Problems Chapter 14: Complex Unknown Problems Chapter 15: NMR Resonance Assignment Problems Chapter 16: NMR Unknown Problems

• ISBN: 978-0-12-384970-0
• Editorial: Elsevier
• Encuadernacion: Rústica
• Páginas: 540
• Fecha Publicación: 20/02/2012
• Nº Volúmenes: 1
• Idioma: Inglés