Hongguanggenin and two hongguanggenin-based saponins, Cantalasaponin-1 and  Ag ameroside-1 were isolated from fermented leaf of Agave americana L. recentl y. On  the basis of 2D NMR techniques, including DQF ¹H-¹H COSY，HSQC，HMBC，H SQC-TOCSY，ROESY and so on, NMR complete assignments of  the three compounds and the glyc osylation shift effect of hongguanggenin were obtained. This led to the revision of some carbon assignments and glycoylation shift effect in the reference.

Compound (Ⅰ) & (Ⅱ) were obtained by the 1,3-dipolar cycloaddition of benzal do xime to 5-(R)-(l-menthyloxy)-2(5H)-furanone. As usual, the structure of an  unknown  compound can only be determined by X-Ray diffraction analysis or by relating it  with the known-configuration compound via chemical method. As the configuration of the former material had been studied by X-Ray diffraction analysis and the known chiral carbon is unaffected during the reaction, the structures of  these two newly obtained products can be simply established by the relationship s between the new-formed and the known chiral centers via the analysis of NMR data (N OEID and HMBC) and the reaction can be shown to occur regioselectivel y.

Piperazinylethylestrone ether is a new synthesized compound that can be used for  the prevention and treatment of osteoporosis and other disease caused by osteop orosis. For further study on it, in this article, the structure of piperazinylet hylestrone ether was established by using a series of spectral techniques (e.g . IR, MS, NMR) especially two-dimensional ¹H-¹H COSY, HMQC and HMBC which can provide valuable information. This combination of these techniques is applicable f or the ass ignment of highly overlapping signals and makes it possible to completely assign  the ¹H-¹H and ¹³C NMR spectra signals of piperazinylethylestrone e ther.

 The reaction system (NH₄)₃VS₄/Et₄Br/CuBr/PPh₃ in CH₂Cl₂ for self -assembling of  [VS₄-Cu_n](n from 3 to 6) clusters was simulated in NMR tube. Aft er the  relationship between the \{\}\+\{51\}V NMR chemical shifts and the number of copper atoms in this family cluster was established theoretically and experime ntally, ⁵¹}V NMR was used as a pseudo -in situ- and real-time method to monitor and identify possible prod ucts during the reaction process. The reaction conditions and mechanism about th e formation of [VS₄-Cu_n] clusters were investigated by changing the m olar ratios of the reactants. The results showed that the concentration of PPh₃ has obvious influence on the ⁵¹V chemical shift, and their mechanism is discussed in detail.

The dynamics of halogen exchange in the mixtures of SnCl₄ and SnBr₄ at di ffer ent concentrations were studied by using ¹¹⁹Sn NMR spectroscopy. Th e spin lattice relaxation times (T₁) and the exchange rate constants (k) were measur ed. The res ults show that the magnetization exchange rate constants in this system are prop ortional to the apparent relaxation rates. It is believed that the system is in  the slow motion limit, since the T₁/T₂ ratio is very large. Theories ind icate th at the spin-lattice relaxation times are proportional to the molecular reorien ta tion correlation time and the correlation time is related to diffusion. It can be concluded that halogen exchange in this system is “diffusion-related”.

The rhizomes of \%Beesia calthaefolia\% yielded a triterpenic hexaglycoside  (1), the  structure of which was characterized by chemical and spectral means  (IR, ESI-MS, ¹H NMR, ¹³C NMR, ¹H-¹H COSY, ¹H -¹H TOCSY, HMQC, HMQC-TOCSY, HMBC) as oleanolic acid-3-O-β-D-gluco pyranosyl (1-3)-α-L-rhamnopyranosyl (1-2)-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1-4)-β-D-glucopyranosyl (1-6)-β-D-glucopyranosyl ester. This paper discribes in detail the application of 2D NMR techniques in the structure el ucidation of this complex natural product.

By using two-dimensional NMR techniques, i.e. Total correlation spectroscopy (TOCSY), two-dimensional nuclear Overhauser enhancement (2D NOESY)，two-dimensional heteronuclear multiple quantum  coherence (HMQC) and two- dimensional heteronuclear multiple-bond correlation(HMBC), ¹H and ¹³C NMRs pectra of the compound 1,2-dihydro-4-(4-hydroxylphenyl)(2H) phthalazin-1- one we re completely assigned. The structural characteristics of the compound were anal ysed and discussed.

The use of DDS chip made it possible to simplify the design and reduce the cost of a pulsed nuclear magnetic resonance spectrometer. Herein, we will int roduce a DDS frequency source on ISA bus. Three DDS chips, AD 7008, were used in t his design. The resolutions of the frequency and the phase of this DDS board are  0.01Hz and 0.09°respectively. The implementation of this frequency source to NMR is discussed. Finally NMR experiment results are shown.

In this article we describe the composite π pulse sequence NMR with phase dis tortion and give a theoretical analysis. During optimization, the elements Z₂₂ of Wigner rotation matrix and it's derivatives with respect to pulse and phase angle were used, and the optimization of  pulse and phase angles were carried out. The subroutines of DB SLSJ an d SOLEQJ were programmed instead of “IMSL”subroutine DBCLSJ to solve the non-linear least square problem and obtain the minimization. The calculations were carried out on PⅢ personal computer. The results show that the optimized values are in agreement with those reported in the reference being obtained from IBM/ 3600 computer and better than those reported using other composite π pulses.

Based on a novel molecular distance-edge vector (VMDE,ν), expressed in the form of potential energy and developed in our laboratories, further syst ematic studies were made on the regularity of chemical shift sum (CSS) for c arbo n-13 nuclear magnetic resonance ¹³C NMR).  With aid of several chemom etrical techniques including multiple linear regression (MLR), stepwise multiple regressi on (SMR) and principal component regression (PCR), various molecular modelling e quations were established to correlate chemical shift sum (CSS) of carbon-13  nucl ear magnetic resonance ¹³C NMR) excellently to the molecular distance-edge vec tor (VMDE) together with the path count of three bonding segment (C-C-C) as foll ows, whose very good results were obtained for the modelled estimation and accur ate prediction with cross validation (CV) of leave-one-out (LOO) procedure: CSS=bν+cp₃=∑^m_j=0b_jν_j+b₁₁p₃=b₀ν+b₁ν₁+b₂ν₂+b₃ν₃+b₄ν₄+b₅ν₅+b₆ν₆+b₇ν₇+b₈ν₈+b₉ν₉+b₁₀ν₁₀+b₁₁p₃=-13.576+22.179ν₁+28.407ν₂+25 .950ν₃+26.690ν₄+14.498ν₅+5.726ν₆-5.379ν₇-3.214ν₈-15.021ν₉ -25.710ν₁₀+12.278p₃  n=63, R=0.997, EV=99.68%, RMS=3.7348, SD=4.1 18, F= 773.116, U=144228.844, Q=864.938; CV: R²_CV=0.980, EV=98.83%, RMS=7.126 1, SD_CV=7.634, F_CV=221.720, U_CV=142121.891, Q_CV=2971 .896. Some reliable correlation models have been developed by using the adjoin structural descriptors through combination of the MDE vector (ν vector) and molecu lar path counts of length three (p₃).

β-cyclodextrin (β-CD) has a central cavity into which organic molecules can enter to form inclusion complexes. We report here ¹H NMR features of a variety of β-CD complexes formed with tryptophan (Try) in a molar ration of  1: 1 which illustrate the enantioselective binding of Try by β-CD . The complex ation between the β-CD  and the racemic Try induced remarkable change in the ¹H chemical shifts of both host and guest. β-CD  inner protons (H3、H5 、Hab) and Try protons shift upfield due to anisotropic shielding. It can be consid ered to be a proof that the complexes are of inclusion-type, involving the inse rt ion of an aromatic group of the guest molecule inside the macrocycle cavity, primarily from the secondary rim of the β-CD. The observed Δδ of proton signals , when enantiopure D-Try or L-Try were used as guest molecules, were entirely  comparable to those induced by the corresponding recemic DL-Try and Δδ of D- Try+β-CD  complex were slightly larger than those of L-Try+β-CD complex. This suggests that the binding modes for both enantiomers of each compound are ess entially the same and the interaction between D-Try and β-CD  is stronger tha n that between L-Try and β-CD  which has been verified by our previous study.  The enantiodiscrimination must be found in subtle geometrical differences.

A group of multi substituted phenols were prepared via intramolecular wittig reaction of a kind of long chain phosphonic ylides.The intermediate   and the  products were analyzed by ¹H NMR and ¹³C NMR. Their chem ical shifts and J-coupling constants were studied. The reaction paths and m echanism were also proposed.

¹³C NMR spectra of 6 new kinds of N-(2-phenyl-1,2,3-triazole-4-actyl)- N′-Arylt hioureas are reported in this paper. These compounds will have potential applica tion value for the use  as plant growth regulators，antitumor medicine or ch emical picki ng agent for fruits. By testing the ¹³C NMR spectra, the structures have been d etermined and all ¹³C NMR peaks have been assigned. The effects of str ucture on  the chemical shifts are discussed. At the same time, the subtituent parameters o f the two new substituent (R₁ and R₂) are given.

1. Studies on ESR instruments, detection methods and applications of  new techniques;
2. Studies on the fundamental theory concerning ESR;
Theoretical exploration to the mathematical; model, calculating and descri bi ng methods for quantitative interrelations between spin spectrum parameters, opt ical spectrum properties, crystal field parameters, magnetic behavior and bond p arameters of paramegnetic species by using the theories and methods of quantum m echanics, group theory and crystal field-ligand field theories. The substance includes: spin-orbital interaction and spin-spin interaction mechanism research ; Calculations for g-tensor, superfine coupling constants, optical spectrum levels and zero-field splitting parameters; Correlation of crystal field param eters with zero-field splitting parameters and g-tensor etc.. At the same  time, chemically induced dynamic electron polarization(CIDEP) as well as its mec hanisms were studied.
3. ESR studies on the inorganic and organic metal coordination compounds a nd inorganic catalysts;
3.1. Basic research on the metal coordination compounds and paramagnetic ions;
3.2. Catalysts and catalytic processes;
3.3. Inorganic solids;
4. Organic free radicals and ionic radicals;
4.1. Long-lived free radicals and ionic radicals;
4.2. Intermediates in organic reactions, mechanisms and kinetics;
4.3. Free radicals in photochemical processes;
4.4. Free radicals in electrode processes and in gas phase reactions;
5. Photoinduced electron transfer and interfacial photocatalysis, micelle  behavior, free radicals in imaging processes;
5.1. Photoinduced electron transfer and photocatalysis in disperse systems  and superfine particle interfaces;
5.2. Free radicals in photosensitization and imaging processes;
6. Studies on the free radicals in biology and life science;
6.1. Probe for especial methods to study biological free radicals; explore  into  the initiation mechanisms for pathological changes of organism and the therapeut ic effects with drugs;
6.2. Mechanism and therapy research for the tissue injury initiated by myocardia lischemia-reperfusion of animals;
6.3. Scavenging effect of medicines and natural antioxidants against free radica ls;
6.4. Phototherapy of some medicines against pathological changes;
7. Research of free radicals for other fields