A new C21-steroidal glycoside from Cynanchum stauntonii

A new C21-steroidal glycoside with two known compounds were isolated from the root of Cynanchum Stauntonii.Based on thespectral analysis,including MS,1H NMR,13C NMR,DEPT,1H-1H COSY,13C-1H COSY,HMQC and HMBC,their chemicalstructures were determinated as glaucogenin-C 3-O-a-L-cymaropyranosyl-(1→4)-b-D-digitoxopyranosyl-(1→4)-β-D-canaropyranoside(1),stigmasterol(2)and ursolic acid(3).     

可逆与不可逆吸附氢在合成甲醇反应中的作用

在自行设计和建立的加压动态分析装置上研究了合成甲醇催化剂上氢的吸附和反应行为。结果表明:在反应条件下催化剂上吸附的氢可分为可逆吸附氢和不可逆吸附氢;不可逆吸附氢又可分为能被CO顶替出来的和不能被CO顶替出来的两部分;能被CO顶替出来的不可逆吸附氢对CO的吸附起促进作用,不能被CO顶替出来的不可逆吸附氢是合成甲醇催化剂必不可少的“组分”或称“促进剂”;同时甲醇的生成是可逆吸附氢与一氧化碳作用的结果。     

Synthesis and Characterization of Tetraosmium Carbonyl Complexes Containing a Bridging CO2 Ligand

Treatment of (thd)H (thd=2,2,6,6-tetramethyl-3,5-heptandionate) with excess Os₃(CO)₁₂ in an autoclave at 180°C gives the formation of a brown metal chain complex [Os₂(CO)₅(thd)₂]₂ (1) and a yellow CO₂ cluster complex [Os₄(-H)(-CO₂)(thd)(CO)₁₃] (2) in low yields. Complex 2 was fully identified by a combination of spectroscopic methods and X-ray diffraction study, showing a unique CO₂ ligand bridging a triosmium metal fragment, Os₃(-H)(CO)₁₀ and a monometallic osmium fragment, Os(CO)₃(thd). Upon treatment of 1 with Me₃NO at an elevated temperature, oxidation of the CO ligand occurred at the position trans to the unique CO₂ ligand on the Os(CO)₃(thd) fragment, giving the formation of a second CO₂ cluster [Os₄(-H)(-CO₂)(thd)(CO)₁₂(NCMe)] (3), which is stabilized by a weakly coordinated acetonitrile molecule.     

A novel trilinear decomposition algorithm： Three-dimension non-negative matrix factorization

Non-negative matrix factorization(NMF)is a technique for dimensionality reduction by placing non-negativity constraints onthe matrix.Based on the PARAFAC model,NMF was extended for three-dimension data decomposition.The three-dimension non-negative matrix factorization(NMF3)algorithm,which was concise and easy to implement,was given in this paper.The NMF3algorithm implementation was based on elements but not on vectors.It could decompose a data array directly without unfolding,which was not similar to that the traditional algorithms do.It has been applied to the simulated data array decomposition andobtained reasonable results.It showed that NMF3 could be introduced for curve resolution in chemometrics.     

CeO2-ZrO2-Y2O3对Pt-Rh型三效催化剂性能的影响

采用共沉淀法技术制备了Ce0.35Zr0.55Y0.10固溶体,并对其进行了比表面积、储氧量的测试和XRD的表征.将其用于低贵金属Pt-Rh型三效催化剂的制备,考察了CeO2-ZrO2-Y2O3对三效催化剂性能的影响.结果表明,Ce0.35Zr0.55Y0.10具有与Ce0.50Zr0.50O2相似的立方结构和相近的储氧量,经高温(1000 ℃)后仍能保持较大的比表面积(38.66 m2·g-1).和含Ce0.50Zr0.50O2的三效催化剂相比,含CeO2-ZrO2-Y2O3的三效催化剂经高温老化后,C3H8,CO,NO仍具有较高的转化率和较低的起燃温度.     

两亲性丙烯酸酯共聚物的聚合研究

利用过氧化苯甲酰为引发剂探讨了甲基丙烯酸β－羟乙酯和丙烯酸长链烷基酯的自由基共聚合。重点讨论了合成条件如溶剂、沉淀剂、引发剂用量、单体配比、反应时间等对共聚反应的影响以及各种聚合条件对该共聚物的组成、结构和性能的影响。并用ＩＲ，ＧＰＣ，＾１３ＣＮＭＲ等手段对共聚物进行了表征。     

Prediction of retention indexes. I. Structure-retention index relationship on apolar columns

A simple method is reported for predicting the retention index (RI) of a chemical compound from the number of carbon and carbon equivalent atoms in the molecule, the RI increment for atom addition and the group retention factors (GRFs) for substituents and functional groups. Atoms other than carbon such as oxygen, nitrogen, sulfur, chlorine, bromine and iodine are assigned carbon atom equivalency of approximately 1, 1, 2, 2, 3 and 4, respectively and are counted for their contribution towards RI prediction. The GRFs of substituents and functional groups are derived from the RIs of reference compounds and series of homologues. Ring structures, ring fusion, ring connection, iso- and neo-carbons, chain branching and unsaturation are also assigned GRFs. The predicted RIs of a number of alicyclic, aliphatic and aromatic hydrocarbons, primary, secondary and tertiary alcohols, phenols, aliphatic amines, aromatic amines, heterocyclics, carboxylic acids, acid esters, aldehydes, ketones, and halogenated compounds, are found to be within +/- 3% of the observed values. The structure-retention index relationship thus developed is extremely useful in the tentative identification of radioactive side products formed in tritium labeling by radiation-induced methods.     

Structure and Magnetic Properties of a Novel Two‐Dimensional Complex from 1, 3, 5‐Benzenetricarboxylate and Neodymium(III) — {[Nd(1, 3, 5‐benzenetricarboxylate)(H2O)4] · H2O}n

A unique neodymium(III) complex, {[Nd(BTC)(H₂O)₄] · H₂O}_n (BTC = 1, 3, 5‐benzenetricarboxylate), was obtained from the reaction between Nd(ClO₄)₃ · xH₂O and Na₃BTC. Coordination bonds, hydrogen bonds, and π‐π stacking form a supramolecular structure with a novel, two‐dimensional framework. The temperature‐dependent magnetic susceptibilities were analyzed by the Curie‐Weiss law; the following values were found C = 1.32, θ = —18.3 K, respectively.