A New Saponin Transformed from Ginsenoside Rh1 by Bacillus subtilis

A novel saponin was isolated from the transformed products of ginsenoside Rh1 by Bacillus subtilis. It‘s structure was determined to be 3-O-β-D-glucopyranosyl-6-O-β-D-glucopyranosyl-20 (S)-protopanaxatriol on the basis of the spectral data.     

5－（4－氯苯基）－10，15，20－三苯基卟啉及其配合物的合成、结构表征及热分解机理

合成了标题卟啉配体及其钴、镍、铜、锌和铁的五种配合物．对它们进行了元素分析、ＵＶ、ＩＲ和荧光光谱等结构表征．用ＤＴＡ、ＴＧ、ＤＳＣ等手段研究了这些新化合物的热稳定性及热分解机理，实验结果与ＨＭＯ方法计算的结果一致．     

2,6-二氯靛酚钠动力学分光光度法测定西红柿及草莓中的抗坏血酸

本文提出用2，6－二氯靛酚纳（以下简写DIS）作氧化剂动力学分光光度测定L－抗坏血酸的新方法。DIS与L－抗坏血酸混合．在固定时间间隔于611nm处测得吸光度A值的变化（△A／△t）与抗坏血酸含量成线性关系。线性范围为0～12mg／L。在样品处理时采用偏磷酸作为提取剂，以减缓抗坏血酸被氧化的速度结果表明，该方法有较高灵敏度，且操作简便，试剂易得，容易推广，是测定水果和蔬菜中L-抗坏血酸的好方法。     

Tandem mass spectrum of a growth hormone secretagogue: Amide bond cleavage and resultant gas-phase rearrangement

Compound 1 [N-[1(R)-[(1,2-dihydro-1-methylsulfonylspiro[3H-indole-3,4'-piperidin]-1'-yl)carbonyl]-2-(phenylmethyloxy)ethyl]-2-amino-2-methylpropanamide](MW 528) is an orally-active growth hormone secretagogue (GHS). As part of a continual effort to analyze the ESI/MS and MSn data of novel drugs, the ESI/MS and MS/MS data of protonated 1 (m/z 529) are analyzed and reported here. The analyses reveal that under low-energy collision-induced dissociation (CID) in an ion trap or a quadrupole collision cell, protonated 1 undergoes a gas-phase rearrangement to form protonated 3 (m/z 357) which competes with the y- and b-type product ions during the amide bond cleavages of protonated 1. It is proposed that when the b-type ion is formed by cleavage of the piperidine amide bond, piperidine (a neutral species) and the b-ion (a cation) form an ion-neutral complex. In this complex, piperidine functions as a nucleophile to attack the benzylic carbon of the b-ion, and the protonated ether group in the b-ion acts as a leaving group, which results in the migration of the benzylic group to the piperidine amine to form protonated 3. Protonated 2 (an analog of 1) was studied under the same experimental conditions. The results show that protonated 2 undergoes a similar rearrangement to form protonated 3. While this rearrangement is a relatively minor fragmentation process for protonated 1, it is a predominant process for protonated 2. This phenomenon is explained in terms of the proposed ion-neutral-complex mechanism.     

中药一枝黄花、黄连、天麻、蛇床子中8种微量元素的测定

采用原子吸收光谱仪对一枝黄花、黄连、天麻、蛇床子中Fe、Ca、Mg、Mn、Cr、Cu、Zn、Pb八种无机元素的含量进行了测定,为进一步研究其药理和用途提供基础。     

In Situ IR Spectroscopic Studies on Molybdenum Nitride Catalysts: Active Sites and Surface Reactions

Recent IR spectroscopic studies on the surface properties of fresh Mo₂N/-Al₂O₃ catalyst are presented in this paper. The surface sites of fresh Mo₂N/-Al₂O₃, both Mo⁺ (0<<2) and N sites, are probed by CO adsorption. Two characteristic IR bands were observed at 2045 and 2200 cm^-1, due to linearly adsorbed CO on Mo and N sites, respectively. The surface N sites are highly reactive and can react with adsorbed CO to form NCO species. Unlike adsorbed CO on reduced passivated one, the adsorbed CO on fresh Mo₂N/-Al₂O₃ behaves similarly to that of group VIII metals, suggesting that fresh nitride resembles noble metals. It is found that the surface of Mo nitrides slowly transformed into sulfide under hydrotreating conditions, which could be the main reason for the activity drop of molybdenum nitride catalysts in the presence of sulfur-containing species. Some surface reactions, such as selective hydrogenation of 1,3-butadiene, isomerization of 1-butene, and hydrodesulfurization of thiophene, were studied on both fresh and reduced passivated Mo₂N/-Al₂O₃ catalysts using IR spectroscopy. The mechanisms of these reactions are proposed. The adsorption and reaction behaviors of these molecules on fresh molybdenum nitride also resemble those on noble metals, manifesting the unique properties of fresh molybdenum nitride catalysts. Mo and N sites are found to play different roles in the adsorption and catalytic reactions on the fresh Mo₂N/-Al₂O₃ catalyst. Generally, Mo sites are the main active sites for the adsorption and reactions of adsorbates; N sites are not directly involved in catalytic reactions but they modify the electronic properties of Mo sites.     

FT-IR evidence for the participation of protonic sites in the heterolytic cleavage of C?H bonds of methane over HZSM-5 zeolite

It has been observed by FT-IR spectroscopy that both kinds of Brönsted acid protons present in HZSM-5 zeolite may be involved in the adsorption of methane at low temperature (173 K) and exchange with CH₄ or CD₄ at high temperature (>500°C). The sites which can adsorb methane at low temperature are the active sites for methane conversion at high temperature. Over HZSM-5 zeolite, the activation of methane is suggested to occur via a heterolytic cleavage of C–H bond with the assistance of protons.     

12-钨磷酸希土盐DMF、DMSO加合物的合成、性质及其热分解动力学常数研究

合成了8种钨磷酸希土盐LnPW₁₂O₄₀·xH₂O(Ln=Y、La、Nd、Sm、Gd、Dy、Ho、Yb)的DMF、DMSO加合物,对加合物进行了组成分析,通过IR光谱、TG-DTA曲线对加合物进行了性质表征,并着重研究了加合物热分解过程的动力学,给出了热分解反应级数n和活化能E.     

5-(4-氯苯基)-10,15,20-三苯基卟啉及其配合物的合成、结构表征及热分解机理

合成了标题卟啉配体及其钴，镍，铜，锌和铁的五种配合物，对它们进行了元素分析，ＵＶ，ＩＲ和荧光光谱等结构表征。用ＤＴＡ，ＴＧ，ＤＳＣ等手段研究了这些新化合物的热稳定性及热分解机理，实验结果与ＨＭＯ方法计算的结果一致。     

Single-crystalline LaB6 nanowires

Lanthanum hexaboride nanowires produced by chemical vapor deposition are single-crystalline and grown along the [111] direction. Streaks appearing in the electron diffraction spots indicate the lateral direction perpendicular to the nanowire growth axis.