Photochemical reactions of benzoin and its derivatives have been investigated by photo-CIDNP technique We could deduce that the photochemical reaction products of (a), (c) and (b), (d) were second recombination products by using free radical-trapping agent with different concentrations. We discussed the reason about the variation of reaction mechanisms of (e) and (f) that differed in substituting groups.

¹³C chemical shifts of 14 kinds of β Naphthoflavoncs and β-Naphthoflavonones have been studied. The chemical shift changes of these compounds are almost identical with those of flavones. All carbon chemical shifts have been assigned on the basis of COSY, HETCOR, HETCOLOC and PBB, DEPT, QUAT experiments

The stereochcmical and structural analysis of two sesquiterpenoids was carried out using nuclear magnetic resonance spectroscopy. Several methods, including ¹H-¹H two-dimensional shift correlation spectroscopy, ¹³C-¹H two-dimensional shift correlation spectroscopy, COLOC (COrrelation spectroscopy via LOng range Coupling), DEPT (Distortionless Enhancement by Polarization Transfer) were used for chemical shift assignment and configurational analysis. Nuclear Overhauser Effect Spectroscopy was used to establish the stereochemistry. This investigation demonstrates the power of two-dimensional NMR techniques and the Nuclear Overhauser Effect (NOE) in the structural determination of natural products.

ESR method has been used to study the dynamics during oxidation process of some acidic phosphate (phosphonate) oxovanadium complexes in THF. The effects of temperature, concentration and nature of complexes on reaction rate and reaction reversibility have been examined. Dynamical parameters-reaction order, reaction rate constant and the activation energy of reaction were calculated.

A new aminoglycoside antibiotic, N-ethylsisomicin, was obtained by synthesis from sisomicin. According to the selective long-range DEPT, ¹³C-¹H COSY and ¹H-¹H COSY experiments,its structure has been elucidated as (1), and total assigment of ¹³C and ¹H NMRspectra achieved.

In practice, LPSVD is one of the most interesting linear-prediction techniques instead of FFT now. In this paper, a method is proposed by means of proportional exponential weighting which is performed after LPSVD, one can keep all characteristic parameters in HRNMR-spectra and improve their resolution, so far as a spectrum can be reconstructed by a group of lines with the same chemical shifts, intensities or integration of FFT spectra.

A method, substituent chemical shift (SCS), which is used in assignments of the ¹³C NMR spectra of ethylene-α-olefine copolymers, is proposed in this paper. The SCS method reveals the corresponding relation bctwce the peaks of spectrum of the copolymer and its sequences. At the same time, the relation is elucidated in a systematic way. The ¹³C NMR spectra of the copolymers are firstly divided into two categories according to the above mentioned relation apparent or not. Secondly, three critcrions for classification are suggested:SCS parameters (S₁ and S₂), spectrum of comonomer homopolymer and electrowithdrawing or electrodonating of substituent. Finally, the SCS method is compared with the Grant-Paul method in many ways.

The correlation functions of the side-groups and side-chains of polymers are obtained for nuclear spin relaxation if the segmental motion of the polymers is described by VJGM model, these functions are derived from unequal two-side and three-site jump internal rotation, diffusion internal rotation, restricted internal rotation and multiple internal rotation. The corresponding spectral density functions are also given, and these functions are used to interpret the nuclear spin relaxation data of the side-groups of some polymers. The average spectral density functions of side-groups are derived under the magic angle spinning, the correlation times and diffusion coefficients of the side-groups of crosslinked poly (methyl methacry-latcs) and solid poly(vinylbutyral) are obtained by using these average spectral density functions. The multiphase structures of nylon 6, poly (ethylenc glycol) and its complexes are investigated with cross-polarization and magic angle spinning techniques.
Three methods using nuclear spin relaxation are presented for studying the intermolecular interaction between polymers and solvents:First, the molecule of tetrachloromethane is used as a "probe" to detect the intermolecular interaction between polymers and tetrachloromethane; Second, the contribution to the spin-lattice relaxation of the quaternary carbons due to the intcrmolecular dipolar interaction is used to calculate the poly (butyl methacrylate)-solvent interaction variables; Third, the intermolecular interaction variables are obtained from the intermolecular heteronuclcar crossrelaxation rates. The heteronuclear cross-relaxation rates are also used to determine the distances among heteromuclei, the general formula for Calculating distances is derived, the experimental results for polymers testify that the formula is correct.
It can be shown with the two-dimensional heteronuclear Overhauser effect technique that the dipolar interaction between the quaternary carbons in polymers and their nearest protons dominates the spin-lattice relaxation of the quaternary carbons. The two-dimensional cadmium-113-proton Overhauser effect spectra of a few cadmium compounds are first reported.

In analysis of sequence structure of ethylenc-α-olefine copolymers methylene (CH₂) βγ and γδ which present the inverse units of comonomer in chain of the copolymer are assigned to VV dyad and EEV triad, respectively. At the same time, both CH₂ δδ and δδ⁺ are assigned to EE dyad. But partition of intensity Iδ⁺δ⁺ characterizing long sequence of ethylene between EE dyad and EEE triad is a key task for treating the sequence distribution of the copolymer. In fact, intensity Iδ⁺δ⁺ should not be divided equally. In order to revise it deduction is performed by Bovey's relationship and Randall's statistical method of polymer sequence. Therefore, the exact representation, exact and approximate solution of revisionary value A are all obtained successfully. The approximate solution obtained under condition of regular chain is identical with Ray's result. When content of comonomer in copolymer is low, the partitions of I_δ⁺δ⁺ between EE and EEE is almost equal.
In level of dyad and triad, there are 13 peaks altogether on the ¹³C NMR spectrum of ethylenc-α-olefine copolymer, where 10 peaks belong to CH₂ and the other 3 to CH. A set of formula calculating sequence distribution could be proposed directly by using those intensities of peaks mentioned above. All information of copolymer sequence structure could be obtained undoubtedly based on it. Hence the method presented here is a satisfactory and universal for studying sequence structure of ethylene-α-olefine copolymers.

The conditions of forming complexes stable in the NMR time scale, for alkali-earth metals-strontium, barium and calcium were investigated. Most suitable ligand for forming such complexes-cryptand C222 was found ¹³C NMR spectra of akali-earth metal and alkali metal-sodium, potassium and lithium complexes in deuterochloroform were studied and interpreted. ¹³C NMR signals of free ligand and its complexes with alkali earth metals which should be used for analytical purposes were assigned. ¹³C NMR spectra of different mixtures of alkali-earth and alkali metals in chloroform were studied. It was shown that in the spectrum of a mixture of barium, calcium and strontium in concentration of 0.001M for each metal under excess amount of free ligand, individual signals corresponding to free ligand and each of the ions were observed. These signals could be integrated with sufficient accuracy and each characterizes concentration of one of the metal ions correspondingly. These observed for the first time results allow to develop, in principle, a new method of inorganic analysis by ¹³C NMR spectroscopy. Suggestions of analytical methods for the NMR-determination of alkali-earth metals in their mixture were discussed in detail. The method could be extended to the analysis of more complicated mixtures including alkali metal series. Spectra were run on Varian XL-200 spectrometer.

The aromaticities (fa) of coals measured at high magnetic field via static ¹³C CP spectra are consistent with those measured at low field by means of high resolution ¹³C CPMAS. Therefore, the demand for fast sample spining was avoided while high NMR detective sensitivity was maintained at high field.

The interaction of Glycyl-L-leudne with trivalent paramagnetic lanthanide cations, Yb³⁺ and Ho³⁺, was studied by ¹³C NMR The lanthanide-induced shifts are separated into contact and dipolar components. It was found that the carbon atom adjacent to the carboxyl group experiences significant contact interaction and therefore the ytterbium-induced shifts cannot be directly used for the analysis of the peptide conformation at least in this case. In aqueous solution (pH 3.31) the peptide is coordinated to the lanthanide ions via its carboxyl group. The peptidc linkage and the amino group are not involved in the coordination. The peptide conformation is analysed from the values of the geometric factor and the results indicate that in the complex the segments C1-C2-C5-C6, C2-C5-C6-C8 and C2-N-C3-C4 arc in trans form while C2-C5-C6-C7 and C1-C2-N-C3 in gauch form.

A flavonoid glycoside has been isolated from Oxytropis glabra D C (Leguminosae). This flavonoid was identified to be 3-O-[α-L-rhamnopvranosyl (1-6)-β-D-glncopyranosyl]-kaempferol by 2D NMR[¹H-¹H and ¹H-¹³C (one-bond and long-range) COSY] and other physical-chemical methods.

¹H cross relaxation time between crystalline and adsorbed waters inCaSO₄ 1/2 H₂O powder was found to be 55.1 ms by use of the Goldman-Shen pulse sequence. In experiment, it was discovered that the narrow component ofthe ¹H spectrum line decays with three time constants. The present paper gives some explanations for the experimental results.

A dedicated ethernet communication protocol-BRUKNET developed by Bruker corporation was introduced. It provides a high speed data communication between ASPECT 2000/3000 and other computers using the ethernet as transfer medium.

In this paper we present the apphcation of proton-detected method to a natural product struturc elucidation and compare with the direct detection.

A precision marginal oscillator-type nuclear quadrupole resonance (NQR) spectrometer using field effect transistors (JFET'S) is described in this paper. The frequency is succesivcly adjustable by several ranges from 14 MHz to 35 MHz, This spectrometer shows a high sensitivity and small wave shape distortion. At room temperature, the measuring accuracy of NQR frequency of ³⁵Cl in polycrystallinc powder of potassium chlorate sample is about 3×10^-6, the signal to noise ratio (S/N) of NQR spectrum of ³⁵Cl in recrystallized sample is greater Than 150. The obtained chlorine's quadrupolc coupling ratio (eQq) ³⁵Cl/(eQq) ³⁷Cl in potassium chlorate, sodium chlorate and sodium chloride art 1.2687363, 1.2687306 and 1.2687661 respectively. The relation of nuclear quadrupole resonance frequency and temperature have been studied by ³⁵Cl in polycrystalline powder sample when the temperature was varied from 77 K to 393 K.