Oxidation of methanol catalyzed by NaOH or HNO₃ modified VO_x/Al₂O₃ was studied by solid-state nuclear magnetic resonance (NMR) spectroscopy. The acid-treated VO_x/Al₂O₃ catalyst showed stronger Bronsted acid sites compared to the unmodified VO_x/Al₂O₃ catalyst, while the base-treated VO_x/Al₂O₃ catalyst had no Bronsted acid sites. As a result, the former exhibited higher selectivity in producing dimethoxymethane from oxidation of methanol whereas the oxidation reaction catalyzed by the later yielded mainly formate. These results indicate that the Bronsted acid sites in VO_x/Al₂O₃ catalysts play a key role in the oxidation reaction converting methanol to dimethoxymethane.

Mogroside Ⅲ was isolated from the fruit of Momordica grosvenori Swingle[Siraitia grosvenorii(Swingle) C. Jeffery]. Mogrol (9β-methyl-19-norlanost-5-ene-3β，11α，24β, 25-tetrol) was derived from mogroside Ⅲ by mild enzymatic hydrolysis. One-dimensional and two-dimensional NMR(including gCOSY，gNOESY，gHSQC and gHMBC) techniques were employed to assign the chemical shifts and elucidate the structures of the compounds. The effects of the substitutent groups on the ¹H and ¹³C chemical shifts of the mogroside were also discussed.

The effects of 1-butanol on temperature-dependent micellization of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer(PEO-PPO-PEO) in D₂O were investigated by 1H nuclear magnetic resonance (NMR) spectroscopy. The chemical shift of the methyl groups in the PPO blocks was used to characterize the aggregation process. It was found that addition of 1-butanol reduced the critical micellization temperature (CMT) of PEO-PPO-PEO in aqueous solution. The chemical shift of the methyl protons in 1-butanol was found to increase after mixing with PEO-PPO-PEO, indicating that the alkyl head of 1-butanol must have interacted with the triblock copolymer and entered into the micellar core. The results of selective ROE experiments further demonstrated that, by such interaction, the alkyl head of 1-butanol was inserted into the hydrophobic micellar core while its hydroxyl tail remained at the micellar shell.

Initiated by poly(hydroxylethyl glutamine), amphiphilic block copolymer of poly(hydroxylethyl glutamine (PHEG)) and poly(γ-benzyl-L-glutamate (PBLG)) was synthesized by polymerization of N-carboxyl anhydride (NCA). NCA monomer was synthesized by reacting γ-benzyl-L-glutamate with triphosgene. The constitution, molecular weight and α-helical structures of the resulting block copolymers were studied by NMR and enzymolysis of the black polymers in vitro was discussed. The results showed that the copolymers with different block-ratio of PHEG/PBLG had different molecular weights, being 1.27×10⁴, 1.75×10⁴, 1.9×10⁴ and 3.60×10⁴ when the A/I ratios were 75∶1, 100∶1, 150∶1 and 200∶1, respectively. The copolymers contained α-helix structures in CHCl₃, which could be converted into random coils with addition of TFA.

Two antibiotic compounds, actinopyrone A(1) and C (2) were separated from lyophilized culture broth of marine fungus Penicilliumsp. and their structures were elucidated with 1D and 2D NMR and HR-ESI-MS. The relative stereochemistry of compounds 1 and 2 was determined by analyzing the NMR NOESY data. Based on the NMR HMBC data, the erroneous chemical shifts of C-21 (H-21) and C-22 (H-22) reported in the literature were corrected.

Perfluoroalkyl-containing coumarin derivatives are well-known for their unique physical and chemical properties and wide applications. In this study，a series of coumarinyl-imine compounds were synthesized from perfluromethylcoumarins. The reactant and the products were characterized by IR，MS，¹H NMR，¹³C NMR and UV. The photo-physical behaviors of these compounds were also investigated.

The principles underlying selection of NMR acquisition parameters (i.e., relaxation delay time, pulse width and number of transient etc.) for quantitative analysis of drugs were discussed in detail. Some requirements on selecting appropriate peaks for quantitative analysis were proposed. We showed that the methyl peak is not suitable for quantitative analysis because it often has long relaxation time. With the principles discussed, the content of vitamin C determined by quantitative NMR analysis was found to have relative standard deviation less than 1%.

Fluoxetine hydrochloride is a novel type of antidepressant that was developed by Eli Lilly and other companies in the United States. It has been used as a first line drug in clinical practice for treating depression, especially gerontal depression. In addition, the compound is also used for treatments of anxiety, chronic pain and eating disorders such as obesity and bulimia. Compared to the traditional tricyclic antidepressants, fluoxetine also exhibits tolerability and safety advantages. The chemical structure of fluoxetine hydrochloride is a bicyclic compound belonging to a class of selective serotonin reuptake inhibitors. In this study, the ¹H and ¹³C NMR spectra of fluoxetine were acquired, completely assigned and analyzed by a combination of 1D (¹H, ¹³C NMR and DEPT) and 2D NMR (¹H-¹H COSY，HSQC and HMBC) techniques. The results obtained in this study will provide a reference for characterization of similar compounds in the future.

In this paper, a AB type of amphiphilic diblock copolymer, composed of methoxy-poly(ethylene glycol) (MeOPEG) as the hydrophilic block and poly(εcaprolactone-co-d, l-lactide) (P(Cap-co-LL)) as the hydrophobic block were synthesized by bulk ring-opening copolymerization using MeOPEG as initiator and LL and Cap as comonomers. The chemical structure of the diblock copolymer MeOPEG-P(Cap-co-LL) was studied by ¹H NMR, ¹³C NMR and HMBC. It was found that random copolymerization of Cap and LL occurred in the formation of P(Cap-co-LL) blocks. The transesterification behavior between the Cap units and the LL units and that between the d-lactide unit and the l-lactide unit in P(Cap-co-LL) were investigated. The yield of the transesterification, the randomness of P(Cap-co-LL) blocks and the average length of caproyl segments and lactidyl segments were calculated using the Bernoulli statistics theory and ¹³C NMR spectra. It was found that both the yield of the transesterification and the randomness of P(Cap-co-LL) block were the highest when the mass ratio of LL to Cap was close to 1∶1. It was also shown that the synthesis condition and the feeding ratio of P(Cap-co-LL) segments have important influences on the transesterification extent, randomness of P(Cap-co-LL) blocks and the average length of caproyl segments and lactidyl segments.

Two-dimensional (2D) nuclear magnetic resonance (NMR) map commonly refers to a plot of diffusion coefficient (D) vs. transverse relaxation time (T₂), which is often used to characterize materials in porous media. The materials with different D and T₂ can be differentiated by such a map. In this paper, we introduced the physical and mathematical models underlying the inversion of 2D NMR map with a global inversion method. The performances of the traditional singular value decomposition (SVD) method and a improved SVD method in inverting 2D NMR maps were compared. The improved SVD method was shown to have advantages such as faster calculation speed and continued distribution of 2D NMR map. The results suggest that the improved SVD method is especially suitable for inversion of data having high signal-to noise ratio (SNR). Quantitative analysis of 2D NMR map was shown to be feasible when the SNR of the original data was greater than 100, while only qualitative analysis was feasible when 60≤SNR<100. The results also showed that 2D NMR maps can be used to differentiate oil and water directly, suggesting that it may provide a promising new technology for NMR logging.

In this paper, we present the hardware design for a general-purpose pulse generator used in NMR spectrometers. The architecture of the pulse generator was significantly simplified by using a field programmable gate array (FPGA) and a synchronous static ram. This design guaranteed the flexibility and easy-to-upgrade feature of the pulse generator. Compared to the conventional designs, the new design allowed finer pulse width and faster switching time. The performance of the new pulse generator was evaluated by NMR experiments.

A method was proposed to measure the gradient waveform on low-field MRI systems with a digital receiver. The principles underlying such a method were discussed in detail. A variable gain amplifier was used in the digital receiver to modulate the amplitude of RF signal according to the audio-frequency (AF) signal. The performance of the digital receiver was tested and evaluated. It was shown that fitting the gradient waveforms measured with the digital receiver could result in correct pre-emphasis parameters, as demonstrated by evidently reduced eddy currents.

磁共振成像；¹H 磁共振波谱；频率校正；肝脏；活体；呼吸运动

Three methoxyflavone compounds: 5, 7, 3′, 4′-tetramethoxyflavone (compound 1）, 5, 7, 3′, 4′, 5′-pentamethoxyflavone (compound 2) and 5,６, 7, 3′,4′,5′-hexamethoxyflavone (compound 3) were separated from the leaves of Murraya exotica L, among which compound 2was reported for the first time. ¹H and ¹³C NMR spectra (including ¹H-¹H COSY, HMQC and HMBC) of the compounds were acquired and assigned. The structures of the compounds were elucidated. The position of the methoxyl group in each of the compounds was determined.

In this study, ¹H and ¹³C NMR spectra of three cephalosporins, cefotetan disodium, ceftriaxone and cefotaxime, were acquired and assigned. It was observed that the ¹³C NMR spectrum of cefotetan disodium showed evident signal splitting when DMSO-d₆ was used as the solvent and such signal splitting was absent with D₂O as the solvent. The results of variable temperature ¹³C NMR spectroscopy further demonstrated that the splitting of cefotetan disodium ¹³C signals was caused by that fact the compound has different conformations in DMSO-d₆.

Fluorine-19 (¹⁹F) isotope has 100% natural abundance, and the magnetic moment and relative NMR sensitivity of 19F nuclei are similar to those of ¹H nuclei. The total range of ¹⁹F NMR chemical shifts is over δ 1 000, giving good spectral resolution. Compared to ¹H NMR, ¹⁹F NMR is more sensitive to the changes in molecular structure and environmental factors, and thus can be used to probe fine structural difference of the compounds. In vivo ¹⁹F NMR spectroscopy provides a highly specific tool for identifying the existence of fluorine-containing drugs and their metabolites in the tissue. In this paper, the ¹⁹F chemical shifts and coupling constants of various fluorine-containing compounds were summarized and reviewed.

In the past two decades, the interactions between peroxovanadates and organic ligands have attracted great interest in both chemistry and biology. In this work, multinuclear NMR (¹H, ¹³C, ¹⁴N, ¹⁵N, and ⁵¹V), multidimensional (DOSY, ¹H-¹H COSY, and ¹³C-¹H COSY), and variable temperature NMR, together with ESI-MS and theoretical calculations were utilized to study the above interaction systems. Through the combination of these methods, structures of all species in the interaction systems were obtained and a better understanding of the experimental phenomena was achieved. These studies shed some light on the essence of the vanadium-contained enzyme such as chloroperoxidase. The main conclusions are summarized as follows:
1. NMR study on the interactions between diperoxovanadates and histidinelike ligands shows that histidine or carnosine coordinates to vanadate(V) by its ε-N, which is the same as His496 in the active site of chloroperoxidase from the fungus Curvularia inaequalis. Theoretical study indicates that the solvation effect plays a key role in stabilizing the products. ESI-MS and theoretical calculations were also performed to explore the different behaviors of the species in the interaction systems in solution and gas phases. The species [OV(O₂)₂(L)₂]^- in gas phase, ever reported to be seven-coordinated, was found to be actually six-coordinated, the same as in solution. The second ligand links to the oxo or peroxo groups through hydrogen bonds.
2. NMR and ESI-MS techniques were used to study the interactions between diperoxovanadates and small organic molecules such as pyridine, imidazole, arginine, picoline ester, and picoline amide. Spectroscopic methods were established to explore this type of interactions. It is worth mentioning that DOSY can be used to analyze the chemical structures and components of mixtures without chemical separation．This makes it important for the investigation of complicated mixtures avoiding time-consuming separation and purification that may destroy the inspected systems.
3. A new diperoxovanadate crystal NH₄{OV(O₂)₂{2-(2′-pyridyl)-imidazole}}·4H₂O was synthesized. The crystal was obtained from the interaction system, NH₄VO₃/H₂O₂/ 2-(2′-pyridyl)imidazole, in aqueous solution under the physiological conditions, and the complex was characterized by solution NMR, IR, X-ray crystal diffraction and elementary analysis. The complex may be of great chemical interest because it is the first diperoxovanadate complex having an asymmetrical N,N′-chelating biheteroaromatic ligand. To the best of our knowledge, its ⁵¹V NMR chemical shift is at the highest field among this kind of complexes reported in the literature.

In the chapter 1 of this dissertation, various solid-state NMR techniques and their applications to the structure and acidity characterization of zeolites as well as the synthesis mechanism of molecular sieves were briefly introduced. Chapter 2 focus on the synthesis of mesoporous solid acids and their NMR characterization. The characterization of crystallization process of two kinds of molecular sieves is the subject of the later two chapters.
Mesoporous ZrO₂, MoO_x/ZrO₂ and WO_x/ZrO₂ materials were prepared and their solid acidity was thoroughly studied by solid-state NMR techniques and DFT calculations. Two distinct types of Br[AKo¨D]nsted acid sites with acid strength stronger than zeolite HZSM-5, comparable to sulfated zirconia, but still weaker than 100% H₂SO₄, were found to be present on the mesporous MoO_x/ZrO₂ and WO_x/ZrO₂ materials. With the help of theoretical calculation, the detailed structures of Br[AKo¨D]nsted sites formed on the surface of the mesoporous catalyst were revealed and the predicted acid strengths of these sites were in good agreement with experimental observations. Besides the weak acidic Zr-OH groups, Lewis acid sites (coordinatively unsaturated Zr⁴⁺ sites) are present on the surface of mesoporous ZrO₂. After the introduction of Mo or W species, the coordination of Mo-OH or W-OH to the unsaturated Zr⁴⁺ sites leads to the appearance of bridging Mo-OH-Zr (or W-OH-Zr) hydroxyl groups that act as Br[AKo¨D]nsted acid sites, and a remarkable decrease in the concentration of Lewis acid sites present on the surface of ZrO₂. The bridging Mo-OH-Zr or W-OH-Zr hydroxyl groups in the form of monomer and oligomer states are responsible for the strong Br[AKo¨D]nsted acidity of the MoO_x/ZrO₂ and WO_x/ZrO₂ materials. Based on our NMR experimental and theoretical calculation results, a possible mechanism was proposed for the formation of acid sites on these mesoporous materials.
Two types of industrially important molecular sives AlPO₄-5 and MgAPO-36 were prepared under the hydrothermal condition. Multinuclear solid-state NMR techniques, combined with powder X-ray diffraction (PXRD), infrared (IR) and SEM spectroscopy, were employed to monitor their crystallization process. For AlPO₄-5, the crystallization process is characterized by the evolution of intermediate gels, in which the long-rang ordering arrangement is probed by PXRD, revealing the threshold of the crystallization around 120 min. The appearance of ³¹P signals at ca. δ -22 and δ -29 due to the structural P-O-Al unit and ¹⁹F signal at δ -120 due to the structural F-Al_pen-O-P unit in the NMR spectra of the series intermediate gel indicates that the crystalline framework is starting to form. The onset of the crystallization is also evidenced by the presence of the pentacoordinated Al in the structural F-Al_pen-O-P unit which is considered to be associated with the ordered framework. More information about the local ordering of the gels is obtained from two-dimensional ²⁷Al→³¹P HETCOR and ³¹P/²⁷Al doubleresonance experiments. In combination with ¹H→³¹P CP/MAS experiments, two micro-domains can be identified in the 120 min heated gel. A possible evolution mechanism consisting of three successive stages is proposed for the crystallization process.
For the magnesium substituted aluminophosphate MgAPO-36, the long-range ordering arrangement of the aged as well as heated intermediate gels were probed by PXRD, revealing that the crystallization of the framework begins at about 1.5 h at 423 K, when the structural Al-O-P and Mg-O-P units from the ATS framework were proved to be formed by ³¹P NMR. After the stick-like crystallites start to form in the semi-crystalline phase, they consequently aggregate into irregular sphere crystals. More information about the local ordering of the gels is obtained from two-dimensional ²⁷Al→³¹P HETCOR and ¹H→³¹P CP/MAS experiments. Different micro-domains can be identified with varied condensation degree of the P coordinating sphere, in which five type of P(nAl) (n=1~4) units were determined by ³¹P/²⁷Al double-resonance experiments. A possible evolution mechanism consisting of three stages is proposed for the crystallization process.

Poly(3-hydroxybutyrate) is one of the most applicative biodegradable polymers. However, its industrial application remains limited, owing to several inherent deficiencies including poor mechanical properties such as brittleness due to its high crystallinity and narrow thermal processing range. To overcome these drawbacks, a number of copolymers with other similar hydroxyalkanoate monomer units have been developed such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate), [P(HB-HV)]. Compared with PHB, these copolymers exhibit outstanding improvement of physical/mechanism properties such as reduced brittleness and enhanced flexibility. Although the preparation and its physical/mechanism properties had been investigated extensively, less work has been done for answering the questions about the molecular basis of them and the relationship between the micaostructural and dynamic properties and their macroscopic properties.
Nafion is one of the most promising proton-exchange membranes used in direct methanol fuel cell (DMFC). In practice, normal Nafion materials are not applicable for DMFC due to poor mechanical stability at temperature above 100 ℃. In order to develop the higher temperature electrolyte materials, many attempts have, so far, been made by modifying the Nafion membrane with various nonconductive inorganic materials. However, little information is available on the molecular basis of such thermal stability improvement. In addition, there are few reports dealing with the molecular structure of these composite materials, the interactions between the inorganic and organic species at the molecular level and structure-property relationships which will undoubtedly be useful for future development of materials.
In this dissertation, combined with XRD various solid state NMR techniques including ¹³C CP MAS、¹³C SPE MAS NMR, proton relaxation induced spectra editing, ¹H spin-diffusion have been employed to investigate the crystallnility and domain structural character. The experimental results show that with the content of HV increasing their crystallinity decrease, domain size of amorphous region increase and domain size of rigid region decrease, which can be seen at the molecular lever that introduction of HV results in the macroscopic properties improvement of PHB. 
Furthermore, ¹H variable temperature relaxation time (T₁, T_1ρ and T₂) measurements have been employed to investigate the molecular motional parameters such as molecular rotational correlation time (τ₀) and active energy (E_a) in the PHB and its copolymers PHBV. The results imply that the higher the content of HV, the faster the molecular motion, the lower the molecular active energy, which can be correlated to their structural and molecular dynamic properties at the molecular lever.
A series of nanocomposites have been prepared from perfluorosulfonylfluoride copolymer resin (Nafion) and layered montmorillonite (MMT) modified with protonated dodecylamine by conventional sol-gel intercalation. FT-IR and ²⁹Si MAS NMR results showed no significant alteration to the lattice structure of m-MMT and addition of the organically modified MMT led to moderate improvement of the thermal stability of Nafion resin though the resin was not intercalated into the m-MMT. ¹⁹F MAS, ¹H-¹³C CP MAS and HETCOR 2D NMR experimental results, combined with XRD and element analysis, indicated strong interactions between NH⁺₃ group of surface absorption of dodecylamine and the SO^-₃ group of the resin side chain. It is concluded that interactions between the resin and the surface absorbed organic modifier probably have some contributions to the resin thermal stability enhancement resulting from addition of m-MMT.

In this dissertation，NMR spectroscopy was used to study the aggregation，micelle structure，dynamics and interactaion of a few typical surfactants in aqueous solution. The results include: The variation of ¹H chemical shift of Sodium 4-Decyl Naphthalene Sulfonate (SDNS) solution at 313 K with different concentrations shows that its Critical Micelle Concentration (CMC) of SDNS lies between 0.82 and 0.92 mmol/L，which is in the same range with that at 298 K (reported). Information provided by relaxation and 2D NOESY spectroscopy suggest that the hydrophobic chains in SDNS micelle at 313 K are packed more tightly than that at 298 K. These hydrophobic chains in SDNS micelles are packed densely and the α- and β-methylene protons next to the naphthalene rings are packed more tightly among the naphthyl rings in the palisade layer to avoid the hydrocarbon-water contact. The T₂ values of protons at different temperatures in the micellar and monomer states show that temperature have a large effect on their motions. The hydration radius of SDNS micelle is approximate 5.3 times of that of monomer by NMR diffusion. The electrostatic repulsion force makes the palisade layer of Sodium Dodecyl Sulfonate (SDSN) micelle packed looser than that of SDNS at 313 K. The characteristics of sodium 4-decyl naphthalene sulfonate (SDNS)/Triton X-100 (TX-100) and sodium dodecyl sulfonate (SDSN)/SDNS mixed micelles of different molar ratios were studied by 1D and 2D ¹H NMR. In the mixed micelle of SDNS/TX-100 the phenoxy rings of the TX-100 are embedded in the near vicinity of the alkyl chains of SDNS and its poly-oxy ethylene segments but the first oxy-ethylene group，to which the phenoxy ring is adjacent，are located near the naphthyl rings. In the mixed micelle of SDNS/SDSN system the sulfonate groups of SDSN are embedded in the naphthyl rings of SDNS，i.e. they are located inner in the mixed hydrophobic micellar core than those of SDNS. Moreover，the naphthyl rings of SDNS separating these sulfonate groups of SDSN may play an active role in weakening the electrostatic repulsion of the negatively charged sulfonate groups，which favors the mixed micelle aggregation.
The measurements of self-diffusion coefficient，spin-spin relaxation and interproton distance at 318 K suggest that N，N′-bis(cetyldimethyl)-α，ω- alkane propane diammonium dibromide (16-3-16) quasi-global micelles are formed in the dilute solution at a concentration of 0.26 mmol/L and the head groups are in a saw-toothed form staying at the surface of the micelle to overcome the strong electrostatic repulsion force. Relaxation measurements obviously show that the spacer chain is rigid in the surface layer of the hydrophobic micellar core and the side alkyl chains of 16-3-16 are packed more tightly than those of N，N′-bis(cetyldimethyl)-α，ω- alkane butane diammonium dibromide (16-4-16) in the micellar core. The line-shape analysis of the methyl protons at the end of the side alkyl chain of 16-3-16 and 16-4-16 suggests that two possible momentary morphologies of their side alkyl chains situated in the micelle， respectively.

Nuclear magnetic resonance (NMR) is an effective method to investigate the microstructure of surfactant micelles and the arrangement of the surfactant molecules in the micellar core. In this dissertation，we studied the aggregation behavior of soluble functional polymer and two kinds of surfactants in aqueous solution by NMR technique. 

1. gemini surfactant 16-4-16

The cationic gemini surfactant of alkanediyl-α，ω-bis(alkyldimethylammonium) bromide is designated as m-s-m，where m and s are the number of carbon atoms in the alkyl chain and the alkanediyl spacer，respectively. The protons of 16-4-16 in the spacer group and a part of hydrophobic protons next to the polar head groups are involved in the surface layer of the micellar core. The hydrophobic protons away from the polar head group are situated internal in the micellar core. The motion of the molecules in the micelles is relatively more restricted than that of their monomeric homologue CTAB. A special arrangement of the molecules in the spherical 16-4-16 micelles is postulated.

2. NaDC and NaDC/CTAB mixed solution
The proton (H3) behaves differently from the other protons in the individual deoxycholate (NaDC) solution. It seems that H3 exits in two states. Its transverse relaxation times obey biexponential decay. We consider that bile salts form head-to-tail molecular pairs via hydrogen bonding between 3-OH and carboxyl oxygen atom in dilute aqueous solution. Furthermore，a 1∶1 mixed micelles form in NADC/CTAB binary aqueous solution. The results of NOESY and ROESY indicate that the polar heads of CTAB are located in the near vicinity of the carboxyl groups of NaDC molecules in the mixed micelles which is due to the strong ionic interaction between these two components.

3. acrylamide/methacrylic acid template copolymer
At quite low pH values，intra-molecular hydrogen bonds between the PAM and PAA blocks lead to compact molecular arrangement and the motion of the phenoxy side chains of the POA blocks is somewhat restricted. With the increase in pH value of the solution，the carboxylic acid gradually dissociates， the electro-static-repulsion of the carboxylic ions and the inter-copolymer hydrogen bonding interactions result in the growth in aggregate size. After the carboxylic acid of the PAA block is completely dissociated in alkaline solution，the electro-static repulsion of the carboxylic ion makes the molecular chain of the copolymer exhibit more outstretched，and the phenoxy side chains have more space to move.