¹³C shifts of amino acids, Gly、Ser and Asp,induced by lanthanide ions,La³⁺、Pr³⁺、Nd³⁺、Eu³⁺、Tb³⁺、Dy³⁺、Ho³⁺、Er³⁺、Tm³⁺ and Yb³⁺, were measured in acidicaqueous solution. An analysis of ¹³C lanthanide-induced shifts (LISs) indicates that these three amino acids are bidentately coordinated to Ln through their α-carboxyl groups with Ln-0 bond length of 0.23nm~0.25nm. γ-carboxyl group is also involved in coordination for aspartic acid. By systematically analyzing ¹³C LISs in this paper and previously reported for various α-amino acid-Ln complexes, the following general conclusions are drawn about hyperfine coupling constant A and geometric factor G for ligand carbon nuclei:
(l)|A(C₀)|<|A(C_α)|with a positive sign for A(C₀) and a negative one for A(C_α); (2) G values are negative for all ligand carbon nuclei with|G(C₀)|>|G(C_α)|.

Semi-empirical molecular orbital methods within the framework of the finite perturbation theory, the FPT-CNDO/INDO methods, which consist of the FPT-CNDO/2 and FPT-INDO methods, are set up for the study of chemical shielding in transition metal compounds, and a corresponding computational program is developed on VAX 11/785 computer to establish a theoretical study of the transition metal chemical shielding by quantum chemistry methods. Application of the methods has been carried out in the calculation of ⁹⁵Mo chemical shielding constants of mononuclear precursors[MoO_nS_4-n]^2-(n=0-4). With the standard CNDO/INDO parameters a linear regression was obtained between the calculated results and the corresponding experimental data:δ_cal=(0.8345 δ_exp-43.83)ppm, with a correlation coefficient of 0.999. Investigation on the calculated electronic configuration confirms that in[MoO_nS_4-n]^2-(n=0-4)⁹⁵Mo chemical shifts are dominated by the d-orbital paramagnetic contribution arising from the d-d transition. Applications were also carried out in the calculation of ⁹⁵Mo chemical shielding constants in Cu-Mo-S clusters. Sensitivity of the method towards CNDO/INDO parameters is surveyed and study is focused on the d-orbital exponent of Mo atom. Adjusted parameters obtained by a trial and error procedure produce results of ⁹⁵Mo chemical shielding constants which agree with the corresponding experimental data:σ_cal¹=(-1.104 δ_exp-1026.8)ppm, with a correlation coefficient of-0.97. Application of the FPT-CNDO/INDO methods is extended to the study of the ⁵⁹Co chemical shielding constants in hexa-coordinated diamagnetic Co(Ⅲ) complexes. Tha calculated values give good agreement with experimental chemical shifts. The discrepancy between the calculated and the experimental chemical shifts can also be attributed to the radial factor effect.
The following conclusions can be made:1. for transition metal elements ⁹⁵Mo and ⁵⁹Co, the chemical shielding constants are dominated by the d-orbital paramagnetic contributions; 2. electron delocalization oceur in the Cu-Mo-S clusters, and diffuse d-orbitals of Mo and Cu atoms are required for the description of the electron distribution in the Cu-Mo-S clusters; 3. among the CNDO/INDO parameters, d-orbital exponents of the transition metal atoms, operating through the radial factor -3>, are the most sensitive ones, and results of modest accuracy can be obtained as long as little adjustment is made to the CNDO/INDO parameters.

A new method is proposed to determine internuclear distances from a 2D NOESY peak intensity or mixing coefficient matrix with a single mixing time. This method is carried out at two stages. At the first stage the symmetrized matrix of nuclear cross relaxation rate is obtained from the regularized 2D NOESY peak intensity or symmetrized mixing coefficient matrix. The calculation in the procedure is quite simple and general. At the second stage the internuclear distances can be extracted directly from the symmetrized nuclear cross relaxation rates and in the course of internuclear distance calculation the internal motion of molecules has been considered. This new method is self-consistent and internuclear distances in spin systems can be determined solely from a 2D NOESY peak intensity or mixing coefficient matrix with a single mixing time.

The conformation of linear enkephalin pentapeptide, N-Tyr¹-Gly²-Gly³-Phe⁴-Leu⁵, in DMSO-d₆ has been investigated on Bruker AM-400 NMR spectrometer at 300K,318K and 336K. The NH-chemical shift temperature gradients, the constraints for torsion angles φ and χ', and the constraints for ¹H-¹H NOE distance were obtained from 1D and 2D NMR measurements. The calculations of enkephalin conformation at 300K, 318K and 336K were carried out on VAX8700 by means of variable target function method. The insight into the backbone conformation is obtained from variable temperature measurements and the results seem to indicate that the backbone is flexible and the peptide is involved in a conformational equilibrium.

4-Substituted-2, 6, 7-trioxa-1-phosphabicyclo[2.2.2] octane-1-oxides (A) (simpled as bicyclic phosphates) are potent convulsants in mamals, and were treated as a research model of polar substituent effects in physical organic chemistry. Their ³¹P NMR can't be explained on the basis of the chemical theory available today.
The ³¹P chemical shifts of compounds (A) exhibit an increasing upfield trend as the electron-withdrawing properties of the substituent X become greater and a reasonable correlation between δ_31P and I_p~o (bond length), △q (charge distribution) is obtained. ¹³C NMR of compounds (A) were also determined. A good relationship between ¹³C-4 chemical shifts and Taft inductive parameters σ_χ was also established. Substitueut effects on ³J coupling constant were studied. ³¹P and ¹³C NMR chemical shifts are explained by our new principle of the spherical symmetry of the electron cloud around the resonant nucleus.

Twenty compounds of thiophosphate and thiophosphoramide containing α-cyno-m-phenoxy benzyl group were synthesized and their ¹H and ³¹P NMR were determined. It was found that there were some relationships between δ_p and the substituted groups. The ¹H spectra of these compounds were observed and discussed.

Information about the behavior of silicate groups during metamictization of zircon is important for a full understanding of the structure of metamict state as well as the mechanism of the process of metamictization of this mineral. Although there is speculation that the creation of 0 vacancies may lead to a progressive polymerization of SiO₄ tetrahedra^[7], no direct experimental evidence supports it up to date. The ²⁹Si MAS NMR results of the present work show that no significant changes in the local structural environment of Si occur at the initial stage of mctamictization. However, Q³ and Q⁴ Si environments were detected in zircons with mediate degree of metamictization (DOM), indicating that the intrease of DOM leads to a polymerization of SiO₄ tetrahedra. The products of polymerization must be amorphous because no crystalline phases other than zircon were detected by XRD. The results of infrared measurments also indicate that domains of amorphous silica may exist in metamict zircons.

It is proved by theory and experiments in this paper that (a) the results of step-progressive accumulation (SPA) is essentially a narrow band-pass filter. The line-shape is a like-sinc function. In the single pulse case, the amplitude of the selected peak will approach to a maximum value with the increment of the accumulation number N. For two pulses case, the maximum amplitude appears only in the optimum N, which depends on the step-length of SPA. (b) The realization of so-called chemical shifts filter (CSF) depends on the offset used in experiment and the coupling of spin system. For weakly coupling spin system, CSF can be observed only if the offset is put on the chemical shift of this system. When the offset is set on one peak of the spectrum, only this peak will be observed. For the strong coupling spin system, CSF is no longer valid. At last, the choice of parameters in SPA experiments and some applications are discussed.

The internal rotation of side chain in AB-crosslinked polymer(i.e.ABCP) based on the prepolymer of polypropyl oxide urethane (PPU) and polymethacrylates (PMAs) was studied by high resolution solid state NMR by means of ¹³C spin-lattice relaxation time, T₁. The ¹³C T₁ values were analyzed by using the average spectral density function for nth internal rotation. The results show that the longer the distance between the main chain and the side chain, the faster the rotation of the side group in PMAs and the rotation of the side-CH₃ group in PPU becomes faster as the glass temperature of PMA decreases. The phase behavior and the compatibility between the two components were also studied by using ¹H T_1ρ, ¹H T₂ and proton spin diffusion measurement. Information about the composition of each phase in corresponding scale and the domain size of the soft phase were obtained.

A paramagnetic center F⁰ was found in thermoluminescent (TL) phosphor LiF:Mg,Cu,irradiated with γ-rays and the g values of its ESR spectrum are g_xx=2.0030, g_yy=2.0450 and g_zz=2.0215 with the splitting values of A_xx=511.04G, A_yy=505.42G, A_zz=507.26G, respectively. The concentration of F⁰ enters decrease with the increase of Mg⁺⁺ concentration. The ENDOR spectrum of the phosphor shows the existance of Cu nuclei near F⁰ enter. The impurity Cu in LiF:Mg,Cu, is in the state of Cu⁺ and its valence did not change directly by γ-irradiation as no ESR signal of Cu⁺⁺ was observed either before or after the irradiation. The axial symmetry ESR signal of Cu⁺⁺ can be found in the ESR spectrum of LiF:Mg,Cu,P before γ-irradiation. After the irradiation the ESR peaks of O^- hole centers and free radicals of PO₃^2- were produced and the environment of Cu⁺⁺ in LiF:Mg,Cu,P phosphor was changed. These results are helpful to explain the function of Cu and P in the thermoluminesence of LiF:Mg,Cu,P.

A new density operator formalism for discribing weakly coupled high-spin systems was proposed. The formula of evolution of density operators under the effect of spin-spin coupling were derived. Some experiments were analysed including refocused INEPT and homonuclear COSY (for D nuclear).

A complete relaxation matrix analysis method is used for processing the peak intensity matrix of phase sensitive NOESY spectrum of ponicidin in which a few cross peaks and diagonal peaks are overlapped. The initial structural model of ponicidin is established by using a series of structure calculation program such as WUPH and MM2. The theoretical peak intensity matrix of NOESY spectrum is calculated based on the molecular model of ponicidin. The mixing peak intensity matrix is consistant with experimental peak intensity matrix in which the intensities of overlapped peaks are replaced by theoretical peaks intensities. Then, the cross relaxation rates between protons are obtained by diagonalizing the mixing peak intensity matrix, and the inter-proton distances are calculated according to l/r_ij⁶∝σ_ij. The calculated results of complete relaxation matrix analysis method are in agreement with the inter-proton distances calculated by molecular mechanics.

2D NMR (¹H-¹H COSY, ¹³C-¹H COSY, COLOC) and X-ray diffraction were used to study the structure of Pd-Ia. The proton signals in ¹H NMR and carbon signals in ¹³C NMR were assigned definitely. The mistake about the assignment of signals of geminal methyls in ¹³C NMR was corrected. Accordingly, some points concerning the determination of C-3' and C-4' relative configuration of the kind of the compounds decided by the value of chemical shifts difference of geminal methyls in ¹³C NMR were revised. It was discovered that the △δ of geminal methyls ≥ 2ppm for cis-configuration and the △δ of geminal methyls ≤ 2ppm for trans-configuration in ¹³C NMR, and △(δC-3' trans-δC-3'cis)>lppm.

Some different phenomena were found between the experiments done with electromagnet spectrometer and those done with superconducting solenoid spectrometer during the study of the intracellular and extracellular Na concentrations. The phenomena were analyzed and may be employed to determine the magnetic moments of rare earth atoms.

Emperical formulas were set up according to the additive theory of chemical shift in this paper. The chemical shifts of 9 quinoline alkaloids were calculated using the proposed emperical formula. Calculated and experimental shifts are in excellent agreement. The chemical shifts of 32 compounds were predicted in addition.

A review of recent developments and applications of high field NMR (i. e., non-imaging) of biological fluids such as urine and plasma to clinical medicine is given. Methods of sample pre-treatment and commonly used NMR techniques are discussed. Finally examples are drawn from the literature of how NMR can be used as an aid in the diagnosis of metabolic and diseased states. It is shown that molecular dynamics, together with concentration, play an important role in determining what species are observable. Molecular dynamics influences relaxation and differences in relaxation between species affords a means of spectral editing. Differences in molecular dynamics may also have diagnostic potential.