Six heteropolyanions belong to P-V-W and V-V-W Keggin structures were synthesized and their ³¹P, ⁵¹V, ¹⁷O NMR spectra were reported in this paper. For the PV_xW_12-xO₄₀^(x+3)-(x=1-4)anions, when x=l the ³¹P, ⁵¹V NMR spectra only contain a single line which is independent on the pH of thesoiution. While x ≥ 2, the number and species of the geometric isomers increase. Their chemical shifts δ_p and δ_v were closely related to the acidity of the solution and x, i. e. δ_p decreases and δ_v incrases respectively with the pH value of the solution and x increases. Finally, the effect of the protonation to the bridged oxygen is also. briefly discussed.

The EPR spectra and magnetic properties of a new binucleacr copper (Ⅱ)complex (DMF)₂]·4DMF are given. Threegroups of lines were observed at 77K and room temperature. Taking account of the magnetic moment and result drived from SCC-EHMO calculation of quantum chemistry, two groups of lines in the EPR spectrum were assigned to the binuc-lear copper (Ⅱ) ions, and the other one was assigned to the triplet state. At room temperature, paramagnetic properties of the compound in solid state are mainly from unpaired electron of tfe triplet state,and at frozen temperature they in solution state depend on the binuclear copper (Ⅱ) ions.
The complex has the following characteristics in electronic structure:rather weak interaction between the two copper (Ⅱ); less residual valence on the two copper (Ⅱ) which are bonded to bridging ligands and terminal ligands. The electronic spin concentration on the binuclear copper (Ⅱ) ions of the complex is~3-4% of that on the mononuclear copper (Ⅱ) compounds, so that the intensities of the two groups of lines drived from the copper (Ⅱ) are rather weak.The levels in the front of molecular orbital are nearly degenerated and electrons become triplet state excited by heat. Thus, a group of lines of triplet state was produced. Therefore, we come to the conclusion that the compound is a new type of binuclear copper (Ⅱ) cluster of triplet state with self-"magnetic dilution".

It is provided that a modified method for selective detection of multiple-quantum coherences in which a pair of Z pulse is used separately at the end of preparation and mixing period in 2D MQ spectrocopy can efficiently decrease the "leakage" from SQC signals and needn't use the digital phaser. Theoretical calculation for AMX spin system with density operators is given and coincides with the results of experiments.

21 groups of peaks at high field and 11 groups of peaks at low field are assigned to individual carbon atoms in various diad environments, based on different compositions of butadiene-styrene copolymers, the empirical calculated values and consulted the data in the literatures. Some new points of view about the assignment have been put forward with the aid of ¹³C NMR spectra recorded on a superconducting NMR spectrometer.

α(p-cl-phcnyl) isoamyl acid is an important intermediate of synthetic pyr-ethroid. There are a chiral center and two prochiral methyl groups iu its structure. In order to understand the co-relation between structure and bioactivily, one must give a detailed observation on its stuclural specifications. Our work included the separation of ¹H and ¹³C signals of the enanfiomers with chiral LSR Eu (hfbc)₃ and LSR Eu (fod)₃, assignments of the diastereotopic methyl groups and the corelation between the magnitude of the anisochrony produced by the methyl groups and neighbor substitutes. Experimenls coincide with the calculation results from a simplified model.

In this paper, a new composite pulse 90°(X)150°(Y)70°(-Y)150°(Y)90° (X) is proposed for broadband heteronuclear decoupling based on theory analysis. Theory and experiments show that the decoupling sequences. NEW-16 and NEW -32, which are incorporated by the new composite pulse, have about 30% wider decoupling bandwidth than the sequences:MLEV-16 and WALTZ-16,which are usually used for broadband decoupling. A circuit is suggested for a practical implementation of most composite pulse decoupling sequences with the Varian XL -200 NMR spectrometer.

A Composite 180° pulse (Indicated by R_x(180)) for the population inversion in solid state NMR systems is presented. Under the strong rf field condition, R_x(180° composite pulse was calculated by use of Coherent Averaging Theory. That the performance of R_x(180° is superior to that of a conventional 180°single pulse is demonstrated by computer simulations and experimental results.

The ¹³C resonances of P (BA/EVA/AA) were assigned by DEPT technique, and the copolymer composition quantitatively determined by ¹³C-NMR method wi-th gated decoupling, increasing delay time and decreasing pulse flip angle.

Two-Dimensional NMR methods were used to assign methyl and methylene group resonances in the NMR spectra of 2-Zn insulin. 10 methyl group of Ile, Leu, Val,Thr resonances are specifically assigned using nuclear overhauser effect (NOESY) spectra of insulin in combination with the information of X-ray structure.
Assignment of other group resonances were based on the analysis of Two-Dimensional spectra of the J-Correlated (COSY).
Insulin exists in the monomeric state at pH 11.0, where spin diffusion is not a serious problem.

In this paper the relationship
δ_CHXYZ=δ_(CH3)2CHZ+△_xy
is proposed for calculating the chemical shift of melhinc proton in the systems containing less-deshielded methine protons which do not obey the Bell, Bowles, and Senese relationship.

A new method of tailored detection of partial NMR spectrum with delaying acquisition time is provided. After theoretical analysis of this method, a good experimental result for strong solvent signal suppression is observed.

The MLEV-16 broadband decoupling scheme is built up on FX-100 NMR spectrometer.By using this decoupling set, the decoupling range is greatly extended and decoupling efficiency is remarkably raised.when applied to a conventional proton decoupling ¹³C NMR experiment, the required decoupling feild for this scheme is reduced at least an order of magnitudein comparison with noise decoupling. Application of this scheme allows the decoupling of fluorine nuclei over 14KHz with primary decoupling feild of FX-100 NMR spectrometer (about 7KHz), t fulfills a basic requirement for the ¹³C {¹⁹F} NMR study of most fluorine compounds.

A nuclear magnetic resonance (NMR) probe was designed to investigate the dynamic behavior of solid states at high temperatures.The probe is fit in a 30-mm magnet gap. The temperatures of sample can be obtained from room temperature to 1300K anb the probe is suitable for proton and other nuclei NMR experiments.

An auxiliary programmable controller for multiple pulse sequences (PCMP) based on a microprocessor is described in the paper. Attached the PCMP to a routine NMR spectrmeter for liquids, many MP experiments can be accomplished, namely, CRAMPS for isotropically chemical shift with J-coupling in organic solids, chemical shift scaling, time-averaged procession frequency cross-polarization, and broad-band decouplig with composite pulses as well, which improve the cababilities of a routine NMR spectrometer greatly.

An IBM-PC/XT computer was used to work for FX-90Q NMR spectrometer in a way of simulating the PerSci Model 8-inch diskette drive. NMR data, as well as programs required for running the whole FX-90Q, could be transferred in parallel mode between the two instruments simply by issuing lightpen commands on FX-90Q's screen. The parallel interface, supported by the interrupt service routine resident in IBM-PC/XT's memory, not only make the IBM-PC/XT replace the PerSci drive for FX-90Q, but also introduce the possibility of building a workstation for FX NMR spectrometer.