氮支套索冠醚V．N－氨乙基单氮杂冠醚合成中氨基的保护研究

研究了一种新的氮支套素冠醚侧链上氨基的保护和脱保护基方法，结果表明，由过量乙二胺与对甲苯磺酰氯反应得到的单保护乙二胺（Ｎ－对甲苯磺酰基乙二胺４ａ），经Ｎ－烷基化环化反应，然后在氢化铝锂存在下脱除保护基，即可制得最佳产率的Ｎ－（２－氨基已基）单氮杂－１２－冠－４（１）．     

Studies on syntheses of biscrown ether compounds

Multi-ester type biscrown ether compound(I) was prepared by the reaction of 6-bromoacetacetic ester dibenzo-16-crown-5(7) with phenyl-methyl ether-2,6-diformic acid potassium salt in anhydrous DMF at refluxed temperature, and color biscrown ether compound(II) was prepared by the reaction of 4′-aminobenzo-15-crown-5(12) with 2,2′(O-formoyl naphthyl)ethyl ether (9) in anhydrous ethanol at 40 C under N₂. New compounds(I, II) were characterized by IR,¹H NMR, MS and elemental analysis. Supported by the National Natural Science Foundation of China Niu Changrong: born in December, 12, 1938, Professor     

Reactions of [FeL2(CH3CN)2](PF6)2 (L = N-pyrimid-2-ylimidazol-ylidene) with N-, P-, O-, and S-donors and its catalytic activity

Reactions of [FeL2(CH3CN)2]2+(L = N-pyrimid-2-ylimidazolylidene) with various N-,P-,O-,and S-donors were investigated.By replacing the labile acetonitrile,various iron-NHC complexes containing additional N-,P-,O-,and S-ligands were prepared.All the iron-NHC complexes were fully characterized by NMR spectroscopy and X-ray crystallography.[FeL2(CH3CN)2]2+ could efficiently catalyze the coupling reactions of various Grignard reagents with heteroaryl bromides or chlorides.     

Fluxes of CO2, N2O and CH4 from a typical temperate grassland in Inner Mongolia and its daily variation

Using a dark enclosed chamber technique, the fluxes of CO₂, N₂O and CH₄ from nature and disturbed grassland were measured on the spot in Inner Mongolian Temperate Grassland along the annual rainfall gradient section ranging from 450 to 200 mm. The results showed that the measured mean fluxes of CO₂, N₂O and CH₄ were (1 180.4 ± 308.7), (0.010 ± 0.004) and (−0.039 ± 0.016) mg · m⁻²/h, respectively. The decrease of the fluxes of CO₂, N₂O and CH₄ follows with that of annual rainfall gradient in the measurement area. Human activities, such as grazing and reclamation are also critical factors to affect the fluxes of these gases from grassland. Daily continuous measurement of CO₂, N₂O and CH₄ fluxes showed a strong diurnal variation with higher emission in the daytime. A good relationship between the fluxes of CO₂, N₂O, CH₄ and temperature was exposed in this study.     

Zn-Co DMC催化合成环氧丙烷-二氧化碳共聚物

制备了基于Zn₃[Co(CN)₆]₂的双金属氰化络合物催化剂,考察了在不同反应条件下催化环氧丙烷/二氧化碳共聚反应的催化性能以及反应条件对产物组成的影响.结果表明：该催化剂能高效催化共聚反应,催化效率可达2 000 g/g Zn₃[Co(CN)₆]₂以上.共聚产物经FT-IR和1H NMR表征,在适宜反应条件下共聚物中二氧化碳摩尔分数可达到0.3以上,产物中也有少量环加成产物碳酸亚丙酯,较低的温度和较高的压力有利于二氧化碳转化为共聚物.     

生物活性多甲氧基黄酮羧酸和氨基酸衍生物的合成及其结构表征

多甲氧基黄酮(PMFs)是一类存在于柑橘属植物中具有显著抗癌、抗炎和抗氧化等生物活性的天然产物。为了提高多甲氧基黄酮类化合物的水溶性和药用价值,以2种来源丰富且抗癌活性高的多甲氧基黄酮橘皮素和川陈皮素为底物,分别经过氧丙酮氧化得到多甲氧基黄酮醇[3-羟基橘皮素(7)和3-羟基川陈皮素(8)],化合物7和化合物8分别在K₂CO₃和N,N-二甲基甲酰胺条件下与氯乙酸乙酯进行Williamson反应,生成了多甲氧基黄酮羧酸酯类衍生物,再经碱性水解合成了2种未见文献报道的多甲氧基黄酮羧酸衍生物[橘皮素-3-O-乙酸(1)和川陈皮素-3-O-乙酸(2)]。化合物1和化合物2在CH₂Cl₂作溶剂、1-(3-二甲基丙胺)-3-乙基碳二亚胺盐酸盐为缩合剂和4-N,N-二甲氨基吡啶为辅助剂的条件下,分别与2种不同的氨基酸甲酯盐酸盐发生缩合反应,得橘皮素和川陈皮素的氨基酸甲酯衍生物,然后经水解反应得到了4种新型多甲氧基黄酮氨基酸衍生物3～6。对所合成的化合物用¹H NMR、¹³C NMR和MS等方法进行了结构表征。     

Synthesis of monosubstituted N-arylamidines by divalent diaminobisphenolate ytterbium complex catalyzed addition of amines to nitriles

Divalent ytterbium complex YbL^（ONNO）（THF）2 （L^（ONNO）= Me2NCH2CH2N（CH2-2-O-3,5-C6H2（^1Bu）2）2） （1） has first been found to serve as a catalyst for addition of amines to nitriles to give monosubstituted N-arylamidine in moderate to good yields. The aromatic amines and nitriles showed better activity. The outcome of the addition reaction was greatly affected by the structure of divalent ytterbium complexes. The reaction mechanism was proposed and the benzonitrile-coordinated divalent ytterbium phenoxide Yb（OAr）2（C6H5CN）（THF）2 （Ar = 2,6-di^tBu-4-MeC6H3） was isolated as one of the intermediates.     

Theoretical characterization of single-electron iodine-bond weak interactions in CH3…I-Y（Y=BH2,H,CH3,C2H3,C2H,CN,NC）systems

Iodine-involved single-electron halogen bonds (SEXBs) weak interactions in the systems of CH3···I-Y(Y = BH2, H, CH3, CH==CH2, C≡CH, CN, NC) were investigated for the first time using B3LYP/6-311++G(d,p) and MP2/aug-cc-pVTZ computational levels (the relativistic effective core potential basis set of Lanl2dz was used on iodine atom). The interaction energies between two moieties with basis set super-position error corrections for the seven complexes are -0.57, -1.36, -3.80, -2.17, -4.49,-6.33 and -8.64 kJ mol-1 (MP2/aug-cc-pVTZ ), respectively, which shows that SEXBs interactions are all weak. Natural bond orbital theory analysis revealed that charges flow from CH3 to the I-Y moiety. The total amount of natural bond orbital charge transfer (ΔNC) from the CH3 radical to I-Y increases in the order CH3…IBH2 < CH3…IH ≈ CH3…ICH3 ≈ CH3···IC2H3 < CH3…ICCH< CH3…ICN< CH3…INC. Atoms-in-molecules theory was used to investigate the topological properties of the bond critical points in the seven SEXB structures.     

Features of major greenhouse gases in loess, Shanxi Province, China

According to the investigations of five loess sections in Shanxi Province, China, it was found that the concentrations of the major greenhouse gases CO₂, CH₄ and N₂O in loess-paleosol sequences are generally high, even sometimes may be several times or scores of times higher than their atmospheric concentrations respectively. Although the CO₂ concentration in the same loess section shows poor regularity among different layers, it increases slowly from north to south in space. The CH₄ concentration in the layers under Malan Loess is much higher than that in the atmosphere, although it is not high in Malan Loess. Most of the δ¹³C values of CO₂ in loess are -11.14‰—15.48‰ (relative to PDB standard). Analysis of carbon isotopic compositions of CO₂ indicates that the main source of CO₂ in loess section is decomposition of ‘stable’ organic matters by microbes. The δ¹³C_g of CO₂ is a little heavier than organic source for exchanging carbon isotope with carbonate in loess. The abundant carbonate in loess not only makes the loess a huge carbon reservior but also adjusts     

B3 型单体及超支化聚醚醚酮的合成与表征

采用亲核取代反应,用间苯三酚与4,4′-二氟二苯酮反应合成一种可用于制备超支化聚芳醚酮的B₃型单体,由MS,IR和¹H NMR等方法对单体进行表征.进一步采用A₂+B₃法制备超支化聚醚醚酮,研究了端基对其热性能、溶液粘度特性的影响.结果表明,羟基封端聚合物玻璃化转变温度、比浓对数粘度高于氟封端聚合物,热稳定性低于氟封端聚合物.     

四氮杂大环冠醚配合物{Me6[14]N4 Cu[Ag(CN)2]2}·2H2O的合成

以丙酮、乙二胺合成六甲基四氮杂大环席夫碱化合物,将其还原成四氮杂大环冠醚配体,然后再和高氯酸铜、二氰合银酸钾反应生成四氮杂大环冠醚配合物{Me6[14]N4cu[Ag(CN)2]2}·2H2O,并用元素分析、红外光谱、紫外光谱等手段对其结构进行了表征.     

Structure and magnetism of carboxylate/EO-azido-mixed-ligands bridged CuII systems

Using two structurally related benzoates bearing different H-bond acceptors as co-ligands, three new azido-Cu^Ⅱ compounds, [Cu（L^1）（N3）（H2O）]n（1）, [Cu（L^1）（N3）（MeOH）]n （2）, and [CuL^2HL^2（N3）3（H2O）]n（3） （HL^1 = 4-nitrobenzoic acid; HL^2= 2-phenyl-4-quinolinecarboxylic acid）, have been synthesized and structurally characterized. 1 is a carboxylate/EO-azido bridged copper chain, forming 3D structure by H-bonds, and 2 has a similar chain structure as 1 but forming a 2D structure by H-bonds, while 3 is a 3D supramolecular network with ternary center H-bonds. Magnetic study indicates that domain ferromagnetic coupling interactions were found to exist in complexes 1 and 3.     

A multiphoton ionization study of acetone using time-of-flight mass spectrometry

The 3p Rydberg states of acetone and photodissociation of the acetone cation were studied using time-of-flight (TOF) mass spectrometry. The 3p Rydberg state spectroscopy of acetone was investigated with linearly polarized two-photon resonance enhanced multiphoton ionization (REMPI) from 320 to 337 nm. Several new transition bands were observed in the spectra. In addition to the CH₃COCH₃ ⁺ ion, CH₃CO⁺ and CH₃ ⁺ fragments were observed. The laser power dependences suggest that the CH₃COCH₃ ⁺, CH₃CO⁺ and CH₃ ⁺ ions are produced in three-, four-, and four-photon processes, respectively. Production of CH₃CO⁺ and CH₃ ⁺involves excitation of the ground state acetone cation by an additional photon and subsequent decomposition of the excited acetone ion. The average translational energies of CH₃CO⁺ and CH₃ ⁺ from dissociation in CH₃COCH₃ ⁺(X) + hv → CH₃CO⁺ + CH₃ and CH₃COCH₃ ⁺(X) + hv → CH₃ ⁺ + CH₃CO, respectively, were derived from the ion TOF peak profiles.     

Rate constants for the reaction of ozone with <Emphasis Type="Italic">n</Emphasis>-butyl, <Emphasis Type="Italic">s</Emphasis>-butyl and <Emphasis Type="Italic">t</Emphasis>-butyl methyl sulfides

The rate constants for the ozone reactions with n-butyl methyl sulfide （n-BMS, CHaCH2CH2CH2SCH3）, sec-butyl methyl sulfide （s-BMS, CH3CH2（CH3）CHSCHa） and tert-butyl methyl sulfide （t-BMS, （CH3）3CSCH3） were measured using our smog chamber under supposedly pseudo-first-order conditions at 30002 K and 760 Torr. The experimental determined rate constants for n-butyl, s-butyl and t-butyl methyl sulfide are （1.23 ± 0.06）×10-19, （5.08 ± 0.19）×10-20 and （2.26 ± 0.14）×10-20 cm3 molecule-1· s-1, respectively. The reactivity-structure relationship of the reactions was discussed and used to illustrate the mechanism of the ozone reaction with thioethers. The results enrich the kinetics data of atmospheric chemistry.     

六(4-乙氧羰苯氧基)三聚磷腈的合成研究

 合成了一种新的高分子模型化合物———六(4-乙氧羰苯氧基)三聚磷腈,用红外光谱、核磁共振氢谱、碳谱和质谱证实了该中间体的结构,用正交试验优化了该中间体的合成方法.结果表明,合成六(4-乙氧羰苯氧基)三聚磷腈的较好方法为:以2.4 g K₂CO₃为催化剂,用1 g六氯三聚磷腈与3.5 g对羟基苯甲酸乙酯在丙酮中回流8 h,产率为93.9%.     

Catalytic self-assembly preparation and characterization of carbon nitride nano-tubes by a solvothermal method

A solvothermal reaction of anhydrous CaNaCl3 and sodium using cyclohexane as solvent and NiCI2 as catalyst precursor has been carried out to prepare carbon nitride nanotubes successfully at 230℃ and 1.8 MPa. The carbon nitride nanotubes were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), electron energy loss spectrum (EELS) and Raman spectrum.SEM and TEM results indicated that the tubes have a length of 20-30 μm, a uniform outer diameter of about 50-60 nm,an inner diameter of 30-40 nm and are highly ordered assembled as bundles. The EELS measurement indicated that the ratio of N/C was about 1.00. The ED and XRD analyses revealed that the tube may have a new CN crystalline structure. The growth mechanism of nanotubes was discussed.     

EPR and UV—vis studies of biomimetic complexes of molybdoenzyme and tungstoenzyme

The biomimetic synthesis and the study of the ca-talysis mechanism of molybdenum and tungsten oxotransfer enzyme have been attracted considerable at-tention for a long time, because the oxotransfer enzymes play an important part in the nitrogen, sulfur and carbon cycles in the biological system[1—4]. With the development of the X-ray crystallography, it is possible to determine the structure of molybdenum and tungsten enzymes. However, due to the complexity and dedicated nature of the protein…     

Theoretical investigation on mechanism of dissociation of furan

Conclusion  According to the calculated results for the dissociation mechanism of C₄H₄O⁺, we come to a conclusion as follows:

石墨相氮化碳表面包覆改善锂离子电池正极材料LiCoO2电化学性能的研究

通过简单的固相法和液相法,分别制备出石墨相氮化碳（g-C₃N₄）表面改性的商品化LiCoO₂复合材料,采用扫描电子显微镜观察改性后的材料,发现g-C₃N₄都均匀地包裹在LiCoO₂表面。两种g-C₃N₄-LiCoO₂复合材料被用作锂离子电池的正极材料,电化学测试结果显示,固相法制得的g-C₃N₄-LiCoO₂复合材料在0.2 C的倍率下充放电测试,首次比容量达167 mA·h·g^-1,循环80次后,比容量仍达132 mA·h·g^-1,高于未经g-C₃N₄包裹的纯LiCoO₂（98 mA·h·g^-1）;液相法制得的Y-C₃N₄-LiCoO₂复合材料循环稳定性明显优于同类材料,循环80次后容量保持率均在95%以上。试验证实,g-C₃N₄表面改性的策略具有一定的实用价值,改性后,材料优异的电化学性能归因于g-C₃N₄的包裹处理,这不仅增强了固体电解质界面（SEI）的稳定性,也抑制了锂离子嵌入/脱出电极材料时引起LiCoO₂体积的变化。     

Investigation of adsorption of surfactant at the air-water interface with quantum chemistry method

Density functional theory （DFT） of quantum chemistry was used to optimize the configuration of the anionic surfactant complexes CH3（CH2）7OSO3^- （H2O）n （n=0-6） and calculate their molecular frequencies at the B3LYP/6-311＋G^＊ level. The interaction of CH3（CH2）7OSO3^- with 1 to 6 water molecules was investigated at the air-water interface with DFT. The results revealed that the hydration shell was formed in the form of H-bond between the hydrophilic group of CH3（CH2）7OSO3^- and 6 waters. The strength of H-bonds belongs to medium. Binding free energy revealed that the hydration shell was stable. The increase of the number of water molecules will cause increases of the total charge of hydrophilic group and S10-O9-C8 bond angle, but decreases of the alkyl chain length and the bond lengths of S10-O11, S10-O12 as well as S10-O13, respectively.