Laser Magnetic Resonance(LMR) Spectroscopic technique employs sweeping magnetic field with ac magnetic flux as modulation to obtain spectra of free radicals. The spectral lines normally have Voigt line shape and different line width in field strength unit. This paper presents a universal simulation technique and program, which can be used to precisely simulate LMR spectra and any other spectra. Its application to the simulation of ¹⁵N ¹⁶O X² Π_3/2 v=1←0, Q₂(2. 5) LMR spectra proved its success and high accuracy. Remarkable agreement between the experimental spectra and the synthesized spectra confirms that it will be a useful computer aid to the analysis of complex spectra.

A new triterpenoid saponin was isolated from the ethanolic extract of the root of Dipsocus japonicus and its structure was established as 3-O-[β-D-glucopyrano-syl(1→4)] [α-L-rhamnopyranosyl(1→3)]-β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl-hederagenin. The results obtained showed that the chemical structure of oligosaccharide chain of the saponin could be elucidated by the combination of 1D-SEMDY and NOE difference spectroscopy in rotating frame techniques, without having recourse to chemical degration or modification. Complete assignments of severely overlapping proton resonance of the sugar residues were obtained.

HMQC-TOCSY experiment is a useful 2D NMR technique for elucidating structures of organic molecules that possess independent spin systems. From HMQC-TOCSY spectrum, we can obtain information of all the proton connectivities in the F₂ dimension and information of the carbon connectivity in the F₁ dimension for a given spin system, so the chemical shifts of both proton and carbon can be simultaneously assigned. In this paper, two examples, annosquamosin A, which is a cyclopeptide, and prostratoside A, which is a triterpenoidal saponin, are given to demonstrate the application of this technique to the natural products.

It has been a continuous interest in measurement of homonuclear scalar coupling constants using two-dimensional NMR spectroscopy because large chemical shift dispersions can efficiently increase spectral resolution. Numerous methods have been developed using homo-and hetero-nuclear correlation and successfully used for a variety of samples. Here we demonstrate an alternative approach based on maximum-quantum correlation NMR spectroscopy (MAXY NMR). The new method combines the advantages of two-dimensional chemical shift dispersion and the spectral editing feature of the MAXY approach and results in separated correlations of CH, CH₂, and CH₃ groups in a single experiment with enhanced chemical shift resolution. The method had been tested on a middle-sized molecule, dexamethasone, and a tridecapeptide, neurotensin.

Two kinds of noncyclic polyether Schiff bases condensed from salicylic aldehyde and diethylene or tetraethylene glycol diamine have been obtained. Four complexes of these Schiff bases with Co(Ⅱ) or Ni(Ⅱ) nitrates have been synthesized and characterized by IR,UV,¹ NMR respectively. The experimental results proved that both of the obtained complexes had scavenging effect on superoxide-anion free radical and showed catalytic activities in the polymerization of methyl methacrylate as well.

ESR technique was used to investigate intermolecular electron transfer reaction between C₆₀ and triethylamine (Et₃N). Photocatalysis of hypocrellin (HB) for the above electron transfer reaction was also discussed in this paper. Intermediates produced in the electron transfer reaction system of Et₃N/C₆₀/HB were directly confirmed by ESR method. The experimental results illustrated that HB acted as a photocatalyst and electron transfer reaction from Et₃N to ground state C₆₀ at room temperature could be realized through two-step electron transfer pathway.

In this paper, the zero-field-splitting parameter b₂⁰ and the electron spectra of ZnAl₂O₄:Cr³⁺ crystal have been studied in terms of the Newman superposition model and the method of the diagonalization Hamiltonian matrices, the calculated results agree well with the experiments. The investigations show that the local structure of the (CrO₆)^9- group in the ZnAl₂O₄:Cr³⁺ Crystal is of the compressed trigonal distortion (△ θ=3.06°), and point out that the spin doublets can not be omitted for the ZFS parameter of the ground state ⁴A₂, and it can be omitted for the ground state g factor.

ESR method was used to study processes and intermediates of photoinduced electron transfer (PET) reaction between C₆₀ and a series of aromatic amine compounds. The results show that PET reactivity of C₆₀ and amines changes with the variation of molecular structure of naphthylamine derivatives. Because of the delocalization and the steric hindrance of aromatic ring, it is more difficult to give out an electron from N-atom for naphthylamines than that for fatty amines. Furthermore, PET between C₆₀ and N phenyl naphthylamines was inhibitted.

Expressions of dipolar spinning-sideband intensities in a ¹H MAS NMR spectrum have been derived for a solid containing molecules and/or groups with fast axial rotation. The sideband intensities can be expanded as even moments of dipolar interactions in its static powder spectrum. The expansion coefficients up to the thirtieth moment have been carried out for practical use. It is sufficient to deal with the ¹H MAS NMR spectra with up to the fifteenth order sidebands.

Using simulation and experiment of NMR with an acetone solution of normal benzene molecules we implement Deutsch's search algorithm, Grover's search algorithm and Control-not Gate. Both simulator and experiment give the same results. It is shown that NMR simulation can give a clearer picture for quantum computation than experiments.

Biexponential diffusion of water in rat brain before and after picrotoxin induced epilepsy was reported for the first time based on MRI study at 4.7T. Self-comparision of the same rat (n=3) in the normal condition and after injection of picrotoxin shows that diffusion coefficients of both fast and slow diffusion components of water were reduced by 16.0% and 23.5%, respectively. Although the proton density was unchanged, the content ratio of the fast and slow diffused water was increased from 1.3:1 to 1.8:1 after the inducement of epilepsy. This may be the source of the increase in transverse relaxation time of water in the epilepsic rat brain.

The alkaloids were isolated from the bulb of Fritillaria wabuensis S.Y.Tang et S.C. Yueh the best "Chuan Bei" cultivated in Sichuan Province, the structure and conformation of an alkaloid was studied and determined as imperialine-β-N-Oxide by ¹H-¹HCOSY、¹³C-¹HCOSY MMR 2D-nuclear magnetic resonance technique, In this paper, we report the detailed research of very rare imperialine-β-N-Oxides in nature using NOESY,HMQC and HMBC 2D NMR new technique.

All of the protons and carbons of antineoplastic antibiotic AD-32 and DM have been fully assigned by NMR spectra including 2D ¹H-¹H COSY, NOESY, ¹³C-¹H COSY,HMQC,HMBC spectra.

In conventional NMR, quadrature detection of free induction decay signal employs two channels of phase sensitive detector. With this technique, phase cycling for canceling the spectral distortion due to unbalance between two channels is indispensable. This makes the experiment time longer than necessary when the signal-to-noise ratio is good enough to ensure one scan sampling. In order to overcome this problem, a digital quadrature detection technique is proposed and carried out on an MSL-300 spectrometer in the present article. The method utilizes only one channel of analog-to-digit conversion. Therefore, distortion caused by the unbalance between two channels can be fully avoided. As a result, no phase cycling for canceling the distortion mentioned above is necessary.

The schemes for solvent signal suppression using selective excitation technique in combination with PFG has been studied com paratively. Four practicable pulse sequences have been investigated. The results show that non-symmetric selective double PFG spin-echo (DPFGSE) is the most efficient solvent signal suppression scheme in both phase property and solvent suppression effect.This scheme has been introduced for solvent signal suppression purposes in 2D gCOSY experiment and a satisfied result has been achieved.