One of the fundamental problems in understanding life science at the molecular level is the relationship among structure, dynamics, and function of proteins. NMR has a unique capacity to investigate dynamics properties of proteins over a range of different time scales with atomic resolution. This review focuses on the experimental and theoretical methods used in heteronuclear spin relaxation measurement for studying protein dynamics, and the parameters describing the protein internal motion as well as the Model-Free method. Finally, some application examples are given in which ¹⁵N relaxation measurements were performed to study the backbone dynamics of protein and protein-ligand complex.

PDC is commonly used to oxidate the hydroxy residue in carbohydrates to produce the corresponding ketone. Treatment of 1, 2-isopropylidene-5-O-benzoyl-α-D-xylofuranose with PDC in CH₂Cl₂ usually yields ketone. It was found in this study, however, a new type higher carbon sugar was obtained when the solvent in the above reaction was changed. The structure of the new higher carbon sugar was elucidated by NMR and ESI-MS/MS. The complete assignment of ¹H and ¹³C NMR chemical shifts of this compound was obtained using 2D NMR techniques, including ¹H-¹H COSY, HMQC and HMBC.

Dexamethasone palmitate incorporated into liposomes (liposteroid) was developed as a targeting antiinflammatory drug (limethason) used mainly for treatment of rheumatoid arthritis. In this study, 1D (¹H, ¹³C NMR and DEPT) and 2D (¹H-¹HCOSY，HMQC and HMBC) NMR spectra of dexamethasone palmitate in chloroform were obtained, assigned and analyzed. The structure of dexamethasone palmitate in chloroform was elucidated by referring to the ¹H and ¹⁹F NMR spectra of dexamethason in the aqueous solution, the standard ¹H and ¹³C NMR spectra of palmitate and the Lindeman-Adams experimental formula.

Poly (organophosphazenes) possesses a backbone of alternating nitrogen and phosphorus atoms with two organic side groups attached to the phosphorus atoms. A unique property of poly (organophosphazenes) is that polymers with tailored physical and chemical properties can be prepared by using appropriate nuclephiles. This feature is useful in developing polymers that are good candidates for biomedical materials. In this study, a mixed substituted poly(organophosphazene) bearing propyl 4-oxybenzoate and glycine ethyl ester side groups was synthesized via macromolecular substitution reactions of poly (dichlorophosphazene) with sodium salt of propyl 4-hydroxybenzoate and glycine ethyl ester. The stepwise substitution reactions were monitored by \{\}\+\{31\}P NMR spectroscopy. ³¹P NMR spectra were acquired repeatedly in a 4-hour interval during the synthetic reaction. The results showed that more than 20 hours and 24 hours were required, respectively, to complete the first step reaction and the second step reaction. Two types of skeleton phosphorus atoms existed in the final polymer product, one with the same two side groups (two -OC₆H₄COOCH₂CH₂CH₃ or two -NHCH₂COOEt) attached, and the other type of phosphorus atoms had two different side groups (one {-OC₆H₄COOCH₂CH₂CH₃} and one -NHCH₂COOEt). The relative content of the propyl 4-oxybenzoate substitute and the glycine ethyl ester substitute was 0.49∶0.51. The results obtained were of interest for understanding the mechanism of the macromolecular substitution reactions, for optimizing the reactive condition for synthesizing the mixed substituted poly(organophosphazene) and for increasing the yield of the polymer product.

Naphtholic naphthalene sulfonate containing tertiary amine group and its derivatives can be used to synthesize universal dyes, cationic dyes and acid dyes. According to the literatures, it can be obtained by condensation of 7-acetamide-4-hydroxy-2-naphthalenesulfonyl chloride with N, N-dimethylethylenediamine, followed by esterfication of the hydroxyl group using excessive sulfonyl chloride in -N, N-dimethylformamide (DMF) in the presence of pyridine. In this paper, an inexpensive synthesis method for naphtholic naphthalene sulfonate is described, the required operations in which are also more convenient as compared with the former methods. Naphtholic naphthalene sulfonate were prepared by treating-N, N-dimethylethylenediamine with 7-acetamide-4-hydroxy-2-naphthalenesulfonyl chloride in acetonitrile in the presence of K₂CO₃. The structure of the compound was elucidated by 1D ¹H and ¹³C NMR and two-dimensional NMR spectroscopy including gCOSY, TOCSY, gHMBC and gHSQC. The complete ¹H and ¹³Cchemical shifts and the ¹H-¹H coupling constants were obtained.

A large number of structure defects and surface functional groups were found to exist in nanocondensed carbon (NCC) and nanodiamond (ND) synthesized by explosive detonation. Results from electron paramagnetic resonance (EPR) showed that there were a lot of free radicals in both NCC and ND. It was also shown that there are great differences in the EPR characteristics between NCC and ND, including the figure, the peak area of the EPR curve, the g- factor, the peak-to-peak line-width ΔH_pp, and so on. In addition, the influences of various factors, such as preparation method, condition of chemical treatment, size of the particles, surface modification and impurity admixture, on the density of free radicals were also discussed.

An efficient algorithm is proposed to reduce the noise in NMR FID signals based on the real-value discrete Gabor transformation developed in our previous work. As NMR FID signals in the time domain are short oscillating decay signals, the FID signals in Gabor transformation domain (i.e., a joint time-frequency domain) are concentrated in very few number of Gabor transformation coefficients, while the noise is fairly distributed among all the coefficients. Therefore, performing a threshold-limiting work in the transform domain can significantly enhance the NMR  FID signals. The theoretical and experimental analyses presented in this paper show that oversampling Gabor transformation is more suitable for NMR FID signal enhancement than critically-sampling transformation, because the synthesis window and its corresponding analysis window in the oversampling case can have better localization in both time domain and frequency domain than that in the critically-sampling case. Furthermore, the oversampling Gabor transform can lead to higher time and frequency resolution than the critically-sampling one.

A novel automatic phase correction method, CLESP, for NMR spectra based on DISPA circle is described in this paper. The phase angles of peaks are determined from the slope of the line connecting two peak points with equal data point density on each side of the peak on the complex plane. The calculated phase angles of the peaks are then used to extract the zero-order and first-order phase correction for the full spectrum by linear regression. In addition to the advantages of being non-iterative, fast, accurate, straightforward, easy to implement, and applicable to partial peaks, CLESP is robust with respect to noise, baseline distortion, peak overlaps, and poor digitization of NMR signals. CLESP algorithm has been successfully implemented in ECNMR , a home-made NMR data-processing software.

JCAMP-DX is a standard file format used internationally for spectra data exchange. The JCAMP-DX 5.0 standard is first explained briefly in this paper. A scheme of managing NMR spectra data based on JCAMP-DX 5.0 standard is then introduced. The scheme was implemented in C⁺⁺, and was used in our home-made NMR data processing software, ECNMR.

An NMR micro-imaging system was developed in our laboratory. In this article, we introduce its control software system, the related software of Spiral imaging and the implementation flow of the Spiral experiment. At last, experiment result using our system was given.

The FSE imaging method was implemented on a clinical MRI scanner. A simple FSE prescan scheme, which could overcome the inherent defect of FSE, was proposed. Customizing method used in software system could control all kinds of prescan combination demanded by MRI experiment. The software system is compatible with most of the NMR spectrometers, and its application on a DRX spectrometer and a 200 mT system was demonstrated.

Perfluromethylcoumarins were synthesized by the reaction of m-substituted phenol and ethyl 4,4,4-trifluoro-2-butynoate or ethyl 4,4,4-trifluoroacetoacetate. The products were analyzed by ¹H NMR, ¹³C NMR, IR, MS and microanalysis. The reaction pathway and mechanism were proposed.

The hydrogen bonds formed and proton exchanging between the -OH groups of PVA under UV irradiation and the protons of residue water in DMSO solvent were studied by ¹H NMR, spin-lattice relaxation and X-ray diffraction. The results indicated that with the increase of UV irradiation time, the intensities of the polymer hydroxyl proton peaks decreased progressively and finally vanished. The linwidth the proton peak of the residual water in the solvent increased progressively with the increase of UV irradiation time, with simultaneous downfield shift of its resonance frequency. This was caused by the hydrogen bonds formed and proton exchanging between the polymer -OH groups and the residual water. In addition, DMSO solution of PVA was studied at different temperatures by ¹H NMR before and after UV radiation. The results showed that with the increase of temperature, the signal intensities of the hydroxyl protons from both the polymer and the residual water decreased, and the resonance frequencies shifted upfield. With the increase of PVA concentration, the hydroxyl proton peaks of PVA before and after irradiation became‘passivated’The data from X-ray diffraction showed that part of hydrogen bonds in PVA were broken after UV irradiation.

The structures of 3α-benzoyloxy-6α-hydroxy-5β-methyl cholanate and 6α-benzoyloxy-3α-hydroxy-5β-methyl cholanate were determined by the combination of 1D and 2D NMR techniques. The carbon and proton chemical shifts of the compounds were assigned, and the characteristics of the chemical shifts for each compound were analyzed.

Recent progresses in the development of MRI contrast agents using complexes of gadolinium, free radical and superparamagnetic iron oxides are reviewed with emphasis on the principle of contrast generation and the functions and properties of these compounds.

It is shown in this article that many analytical problems regarding structure/composition determination of petrochemical products and catalysts used in petrochemical processing, which are difficult to solve by other instrumental methods, can be resolved by using high-resolution nuclear magnetic resonance techniques. More and more recent evidence suggests that NMR has become a powerful analytical tool for the petrochemical industry.