The ¹³C CP MAS NMR spectra of silkworm cocoon from Henan Bombyx mori (B mori), Antheraea pernyi (A. pernyi), artificial white cocoon and their silk fibroins in solid state were first recorded on Bruker AC-250 and MSL-400 NMR spectrometer. The ¹³C NMR spectral lines were assigned and the difference in secondary structure of silk protein from A. pernyi yellow and white cocoon was revealed.

This paper reports conformational investigations of small molecules and structrure determinations of hydroxyl substituted coumanns using NMR difference NOE technique.

Laser magnetic resonance (LMR) spectroscopy technique was used to study the linewidth and pressure broadening of the spectral lines of v₃ band of NO₂. The pressure broadening coefficients γ_{NO2-NO2N2O4CO2}⁰ were determined to be 5.8±.6,1.8±.4,1.7±.4MHz/Torr (HWHM) at 275K respectively. The obtaining of these linewidth parameters is of considerable importance to the air pollution monitoring of NO₂.

Based on the prony algorithm, Delsuc's approach for prediction of NMR spectra is more useful in practice. However, missing lines and spurious signals will be und time by time in the very noisy spectra and one must get the periori knowleage of the number of peaks in a spectrum.
In this paper, the recursive process has been traced. It is found that the criterion r_min in Delsuc's approach is very difficult to be chosen. Some peaks will be missed if r_min is too small. Otherwise, the spursious signals will appear if it becomes larger. Meanwhile, the coherency of sampling points in weak signal is less than that in strong signals due to the influence of noise which will increase the instability of data in recursive process. Here an additional criterion of peak area is adopted to remove the drawbacks of Delsuc's approach The success of this suggestion is proved by simulation and experiment.

According to the contribution of main structural units to the peaks, six equations for diad concentrations in terms of peak intensity have been derived based on the ¹³C-NMR spectrum assignments of hydrogenated styrene-butadiene copolymers (HPBS). Many structural data, including the concentrations of diads, monomer units and their blocks, the number-average sequence lengths of each monomer unit and other structural parameters, were calculated. Basically consistent results from ¹H-and ¹³C-NMR spectra were obtained for the styrene-butadiene copolymers before and after hydrogenation. Furthermore, the correlation between the microstructure of HPBS and its behavior serving as viscosity index improver has been preliminarily investigated. The results would provide a basis for preparation of HPBS with better performance.

In this paper, 2D long-range ¹³C-¹H heteionuctear chemical shift correlation spectroscopy, in combination with ¹³C-¹H heteronuclear chemical shift spectroscopy and ¹H-¹H homonuclear chemical shift spectroscopy, have been used to elucidate the structure of an ocotillol-type saponin (OTS) which was first separated from the leaves of Panax Quinquefolium L., and the results were also confirmed by element analysis and FAB-MS techniques.

The NMR spectra of oleanane type triterpenoids, glyyunnansapogenins (I-IX) have been investigated. The assignments of the ¹³C-NMR signals have been made by using PBB, INEPT, DEPT methods and the known chemical shift rules. It was found that the oxygenated substitute at the angular methyl group can be easily recognized by inspecting the chemical shifts of the angular methyl groups, and the effects of oxygenated substitutes to the rings are also analyzed. In the assignments of the ¹³C-NMR signals of olean-11,13 (18)-diene compounds, the junction between D and E ring is considered to be the same as that of 18α-H olean-12-en, compounds. The known chemical shift rules used to the olean-12-en, 11-oxo, 30(or 29) →18β (or 18α) lactone arc also discussed. Another regular chemical shift for the oleanane compounds with one OAc group subsitituted in D or E ring has also been found.

EPR and ¹³C NMR techniques were used systematically to study the products formed by the reaction of sugar with amino acid. The characteristic hyperfine structure of EPR spectra of the products depended mainly upon the structure of amino acids. The chemical shifts of ¹³C NMR spectra of the products showed that the principal structure would be 2,5-piperazine dione. The results lead to the assumption of the identity as l,4-disubstituted-2,5-piperazme dione. The EPR spectral analyses and the assumed structures were strongly supported by the close agreement between the observed spectra and those simulated on ASPECT 2000 computer. The proposed probable mechanism of the reaction of sugar with amino acid is presented in this paper.

The effect of MgCl₂ on the natural DNA solution conformation was studied by ³¹P NMR, MgCl₂ induced transition from B-DNA to Z-DNA was obversed. The mechanism was discussed.

The magnetic characterization of some cobalt compounds containing o-benzenedithiol or o-mercaptophenol has been investigated by ¹H NMR spcctroscopy and magnetic susceptibility. Their electronic structures were also discussed.

L-Tryptophanc methyl ester reacts with corresponding monoacetal of malonaldchydc under Pictct-Spenglcr conditions followed by Michael additions of methyl vinyl ketone to give diastereoisomcrs of tetrahydro-β-carbolines l_a,b, 2_a,b and 3_a,b. Their COSY and NOESY 2D-NMR spectroscopy were studied here. It was shown that in 1_a, 2_a, and 3_a, there were NOE relationships between 3-H and 3'-H, in l_b, 2_b, and 3_b however there were NOE relationships between OCH₃ and CO₂CH₃ (for l_b and 2_b) or between 5'-CH₃ and CO₂CH₃ (for 3_b). Based on the results of NOE and the help of Dreiding Stereomodels their conformations were discussed.

³¹P NMR spectrum of bis-(3-diphenylphosphinopropyl)-phenylphosphinerhodium chloride Rh (ttp) Cl in different solvents were studied. It was found that in methylene chloride and chloroform Rh (ttp) Cl has dramatically different chemical shifts and coupling constants, whereas solvents CH₃CN, DMF, DMSO do not react with Rh(ttp) Cl. It was suggested that methylene chloride and chloroform act as Lewis acid with Rh(ttp)CI. We suggest that methylene chloride and chloroform be avoided when one wants to draw correlations between X-ray structure and XMR data of metal complexes.

An echo sequence with broad band excitation bandwidth and shortexcitation time is proposed for use in deuterium NMR system in powders, which consists of four 90°pulses and an additional single pulse with flip angle of about 45° It is shown by numerical calculations that the excitation bandwidth of the ECHO sequence is nearly twice as broad as that of the conventional quadrupole echo sequence. The superiority of the ECHO sequence over the conventional quadrupole echo sequence is confirmed experimentally by a ²D-PMMA powder sample.

The multidimensional NMR data acquisition on a routine spectrometer and processing on universal computer is described. The processing includes data format conversion, one, two and three dimensional NMR data processing programs, spectra display and plot program. The FFT formula for processing data obtained by sequence acquisition mode was derived, and other detail technical problems of developing the programs are discussed. As an example, H-H-C correlation 3D NMR spectrum of propyl alcohol is recorded and processed on VAX computer, the spectrum is displayed in Figure 1.