The hydrogen bonding interactions in a series of cobaltic supramolecular complexes [12] aneN₄[Co(CN)₆], [18] aneN₆[Co(CN)₆], [24]aneN₈[Co(CN)₆], [16] aneN₄[Co(CN)₆], [24] aneN_6^[Co(CN)₆] and [32] aneN₈[Co(CN)_6^] were studies and found to be closely related to the molecular conformations in the aqueous solution. Such interactions caused the ⁵⁹Co chemical shifts to move towards upfield, and the quadrupolar interaction to change as well. It was observed in this study that stronger hydrogen bonding resulted in larger upfield shift of the ⁵⁹Co chemical shifts and higher quadrupolar interaction in the cobaltic supramolecular complexes. On the other hand, larger supramolecular sizes resulted in longer molecular rotational correlation time τ_c and shorter ⁵⁹Co longitudinal relaxation time (T₁).  In summary, ⁵⁹Co NMR proves to be an ideal probe to investigate the second sphere or weak interaction in the cobaltic supramolecular complexes in addition to the small molecules.

In this paper, the basic theory about two-dimensional electron spin resonance (2D ESR) spectroscopy obtained from continuous-wave ESR (CW-ESR) spectra is described. Synchronous and asynchronous 2D ESR correlation spectra defined by two independent magnetic field variable axes are generated by a correlation analysis of dynamic fluctuations of ESR signals induced by an external perturbation. An example of 2D ESR spectra is presented for a radical produced by self-trapping of 2-methyl-2-nitrosopropane (MNP) under UV irradiation. Potential applications of this new 2D ESR technique are discussed.

The EPR parameters and the hyper-fine electronic spectra of Cr³⁺: MgAl₂O₄ crystal were studied using the full energy matrices and the spin Hamiltonian theory. Spinspin (SS) interaction and spin-other-orbit (SOO) interaction were taken into account. The results obtained by theoretical simulation were in good agreement with the experimental findings. The microscopic mechanisms determining the EPR parameters for the ⁴A₂(3d3) state were also studied. The EPR parameters were found to be dependent on four microscopic mechanisms, namely the SO coupling mechanism, the SS coupling mechanism, the SOO coupling mechanism and the SO～SS～SOO combined coupling mechanism. Among the mechanisms, the SO coupling mechanism seemed to be the most important.

Configuration and performance features of the newly developed L-band three-dimensional ESR imaging system were introduced. The main components of the ESRI system include a set of L-band ESR spectrometer, the three dimensional gradient magnetic field system  and the imaging reconstruction software. The microwave system worked at the frequency of 1.05 GHz with more than 500 mW microwave power. The phase-locking receiver was set to work at 100 kHz modulation frequency with a modulation amplitude of more than 0.5 mT. Receiver gain could be set up to 1×10⁺⁶ and time constant was adjustable from 0.02 ms to 1 s. The sample cavity was a threelooptwogap reentrance one which had an unloaded Q-value of more than 1 000 and had a cylindrical sensitive volume of 2 cm in diameter and 3 cm in length. The maximum gradient strength could be 2 mT/cm with spatial linearity of better than 5% in all three dimensions. Field stability was about 10^-5. Main magnet strength and the scanning range of the magnetic field were 1.6～96 mT and 0.2～16 mT respectively. Data system worked on a 12-bit A/D card for data acquisition. Three channels of 8-bit D/A converter were used for gradient control. Spectrum processing functions included integration, base line correction, resolution enhancement, spectrum deconvolution and noise filtering. Imaging functions included two and three dimensional imaging reconstruction, 2D image display of spin intensity isograms, 3D image display of contour and computed tomography. The preliminary results of imaging of biological equivalent samples, such as large volume solution phantoms, suggested that the present ESRI system was capable of imaging biological samples in combination with spin labeling techniques.

Based on a miniaturized microwave cavity developed by ourselves and the separated filter technique, a new type of cavity-cell assembly for gas cell rubidium frequency standards was made. The light shift characteristics of the assembly were studied, and the conditions for minimum light shift and temperature coefficient were determined. The operating temperature for minimum light shift was found to be 68 ℃ for the new assembly, 5～10 ℃ lower than that for the conventional systems. The light shift coefficient under the optimized conditions was
7.2×10^-12/10%. The light shift effect in the new assembly was independent on the parameters of the absorption cell, thus could be minimized by optimizing only the parameters of the filter cell so that the parameter optimizing process was greatly simplified.

Aqueous solutions of sodium dodecyl sulfate (SDS) at various concentrations in 2 g/L polyvinylpyrrolidone (PVP) and 2 g/L polyvinyl alcohol (PVA), respectively, were studied by ¹H NMR. Two-dimensional nuclear Overhauser enhancement spectroscopy (NOESY) experiments show that SDS starts to micellize at a concentration of 2.5 mmol/L, with PVP solubilized in the interior of the micelles. At
SDS concentrations lower than 2.5 mmol/L, no significant interaction could be detected. Spin-spin relaxation measurements support this conclusion. The interaction between PVA and SDS was hardly detected.

Cagelike silsesquioxane is a special type of polyhedral compound composed of both organic and inorganic molecules, whose structure can be determined effectively by ²⁹Si NMR. In this article, we studied the structures of six kinds of cage-like octa silsesquioxane by NMR. Combining experimental data and empirical treatment, it was found that the electronegativity of the subsistent on the cage has important influences on the silicon chemical shifts. The structures of the subsistent on cage-like silsesquioxane were determined by using ¹H and ¹³C NMR.

A potent 5-HT_1B/1D receptor agonist, zolmitriptan, has been synthesized by the Fisher indole reaction. Its structure was elucidated by NMR using the selective long-range INEPT technique and the homo-/hetero-nuclear 2D NMR techniques.

¹H NMR spectroscopy with two-dimensional nuclear Overhauser enhancement (2D NOESY) measurements was used to study the aggregation behavior of a novel hydrophobically associating copolymer composed mainly of acrylamide (AM) and a small amount of 2phenoxyethyl acrylate (POEA). The results show that aggregation of the copolymer PAM/POEA mainly derives from the interactions among the phenoxy groups and that between the phenoxy group and the acrylamide backbone. 2D NOESY experiments unambiguously show that, in the  POEA/PAM aggregates, the phenoxy groups of the hydrophobic parts of POEA are possibly located in the vicinity of the acrylamide backbones.

In this paper，NMR characteristics of two keto-isophorone ketals were reported. By comparing with the NMR spectra of the compound (2)
reported in the references and with the NMR spectra of ketoisophorone itself， the ¹H and ¹³C chemical shifts of keto-isophorone ketal (3) were assigned and analyzed and its structure was determined.

The structures of thirteen 5,10-dihydrophenophosphazine derivatives were elucidated by ¹H, ¹³C and two-dimensional NMR. The ¹H and ¹³C chemical shifts were assigned, and the coupling constants between ¹⁹P and ¹H/¹³C were determined accurately. The factors affecting coupling constants were also investigated.

The Atheron-Todd reaction has been applied extensively to the synthesis of phosphates and phosphoroamidates. In this study, aminophenols and dihydroxybenzenes were phosphoylated by a modified Atheron-Todd procedure, in which DEPH and etrachloromethane were added to the mixed solution of phenol, triethylamine and dioxane and the mixed solution of phenols, triethylamine and dioxane, respectively. The target phosphates were obtained with good yields. Their structures were elucidated by NMR and ESI-MS.

Metolazone is a well-known quinazolinone diuretic widely used for the treatment of congestive heart failure and high blood pressure. Metolazone was first synthesized in 1967 with its first detailed pharmacological evaluation done in 1969. Previous results only reported part of its ¹H NMR data, and the detailed elucidation is yet to be performed. In this paper, using a combination of 1D and 2D NMR
techniques, the ¹H and ¹³C NMR spectra of metolazone were completely assigned and analyzed. The characteristics of its NMR data were also discussed.

This review first summarizes the general theory of spin diffusion in solids, including semi-classical description and the more exact approach, i.e., density matrix method based on projection operator formalism. The calculation of spin diffusion rate is demonstrated with two typical cases: a spin-1/2 pair and the central transition of a spin-3/2 pair. The analysis of spectral spin diffusion of halfinteger quadrupolar spins is emphasized, highlighting the influence of pulse strength, width as well as sample spinning speed.

There are a great number of physiological and biochemical reactions inside biological tissues, which are either independent or correlated to each other. Useful information can be obtained by Nuclear Magnetic Resonance (NMR) technique in studying the metabolic processes. There are presently three kinds of NMR techniques for studying biological tissues: ① in vivo Magnetic Resonance Spectroscopy (MRS); ② High-Resolution in vitro Nuclear Magnetic Resonance (HR-NMR); ③ High-Resolution in vitro Magic Angle Spinning Nuclear Magnetic Resonance (HR-MAS NMR), each has its own advantages and disadvantages and are complementary to each other. In this article, progresses in the NMR studies of biological tissues are reviewed.

Solid-state NMR is a powerful tool in study of polymer microstructure and dynamics in solid state. Researches in this field are progressing rapidly along with the development of new NMR methods and of spectrometer techniques.  In this paper, we briefly reviewed the applications and the important progress of solidstate NMR technique on the study of polymer microstructures. Some of NMR
 experiments in this paper were carried out on a Varian UNITYplus 400 MHz NMR spectrometer.