Proton magnetic resonance spectroscopy parameters

To detect dynamic featnres of colloidal preparations, additional methods are required. Nuclear magnetic resonance spectroscopy allows a rapid, repeatable, and noninvasive measurement of the physical parameters of lipid matrices withont sample preparation (e.g., dilution of the probe) [26,27]. Decreased lipid mobility resnlts in a remarkable broadening of the signals of lipid protons, which allows the differentiation of SLN and supercooled melts. Because of the different chemical shifts, it is possible to attribute the nuclear magnetic resonance signal to particnlar molecnles or their segments. 

When using the thermal process for the production of SCT pitch, the temperature and time are important process parameters. The higher the temperature used, the higher is the aromaticity and condensation of the aromatic rings. The average carbon and proton distributions (determined by Nuclear Magnetic Resonance Spectroscopy) of SCT pitches prepared by thermal process at 390°C and 430°C are presented in Table III. 

Stereochemical and kinetic analyses of the Brpnsted acid-catalysed intramolecular hydroamination/deuterioamination of the electronically non-activated cyclic alkene (13) with a neighbouring sulfonamide nucleophile have been found to proceed as an anh-addition (>90%) across the C=C bond to produce (15). No loss of the label was observed by and NMR (nuclear magnetic resonance) spectroscopies and mass spectrometry (MS). The reaction follows the second-order kinetic law rate = 2 [TfOH] [13] with the activation parameters being = 9.1 0.5 kcal moP and = -35 5 cal moP An inverse a-secondary kinetic isotope effect of d/ h = (1-15 0.03), observed for (13) deuteration at C(2), indicates a partial CN bond formation in the transition state (14). The results are consistent with a mechanism involving concerted, intermolecular proton transfer from an N-protonated sulfonamide to the alkenyl C(3) position coupled with an intramolecular anti-addition by the sulfonamide group. ... 

Over the past 40 years fluorine nuclear magnetic resonance (19F-NMR) spectroscopy has become the most prominent instrumental method for structure elucidation of organofluorine compounds. Consequently the amount of spectral data published has grown almost exponentially Unfortunately NMR data for fluonnated compounds are not as well, or as easily, organized as proton data To facilitate retrieval of fluorine NMR information and comparison of data, acquisition parameters should be clearly defined Guidelines for publication of NMR data have been established by the International Union for Pure and Applied Chemistry (IUPAC) [7] The following niles for acquisition and reporting of NMR data should be strictly observed... 

Millimeter wave spectroscopy with a free space cell such as a Broida oven is more sensitive than lower frequency microwave spectroscopy. However, the higher J transitions monitored by millimeter wave spectroscopy often do not show the effects of hyperfine structure. In the case of CaOH and SrOH, the proton hyperfine structure was measured in beautiful pump-probe microwave optical double resonance experiments in the Steimle group [24,68], They adapted the classic atomic beam magnetic resonance experiments to work with a pulsed laser vaporization source and replaced the microwave fields in the A and C regions by optical fields (Fig. 15). These sensitive, high-precision measurements yielded a very small value for the proton Fermi contact parameter (bF), consistent with ionic bonding and a... 

---