乙萘酚在纳米银/壳聚糖-乙炔黑复合修饰电极上的电化学行为及测定

制备了纳米银/壳聚糖(AgCS)与乙炔黑(AB)复合修饰电极(AgCS-AB/GCE),用紫外可见分光光度法、扫描电镜法对AgCS进行表征,用交流阻抗法对不同电极进行表征,用循环伏安法(CV)研究了乙萘酚(β-N)在AgCS-AB/GCE上的循环伏安行为。结果表明,在pH 6.5的PBS缓冲液中,β-N在该修饰电极上出现一明显氧化峰,在60~240 mV/s扫速范围内,β-N的氧化峰电流(I pa)与对应扫速平方根(v1/2)呈良好的线性关系,表明β-N在该电极上的电化学过程为受扩散控制的不可逆过程。计算了电极过程的动力学参数,运用方波伏安法测定不同浓度β-N的方波伏安曲线,结果表明β-N的氧化峰电流与其浓度在3.0×10-7~2.0×10-4mol/L范围内呈良好线性关系(r=0.996),检出限(S/N=3)为1.24×10-7mol/L,加标回收率为99%~105%。     

大气条件下O3与乙炔反应速率常数的测定

O₃是对流层大气中一种重要的氧化剂, 其与反应活性气体的反应是大气对流层中重要的反应过程, 对于研究空气污染的对策有重要意义. 我们使用自行建设的烟雾箱模拟反应装置, 结合O₃分析仪和气相色谱研究了O₃和乙炔的反应. 研究测得O₃和乙炔在室温下(15 ℃)反应的4次实验的速率常数的平均值为4.13×10^－21 cm³•molecule^－1•s^－1, 其变动系数为7%. 与文献中采用其它方法得到的实验值相吻合. 所得结果表明, 我们测定的反应速率常数有较高的精密度, 我们所建的大气反应烟雾箱模拟系统是可靠的, 可以用于大气O₃浓度条件下O₃的其它大气化学反应过程的深入研究, 为进一步深入研究大气中其它重要反应活性气体的化学反应提供了一定的基础.     

Multimolecular self-organization of acetylene and arylamines into 1-aryl-3-ethyl-4-vinylpyrroles in the KOBut/DMSO system

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Computational insights into the coupling mechanism of benzoic acid,phenoxy acetylene and dihydroisoquinoline catalyzed by silver ion as polarizer and stabilizer

The coupling mechanism of benzoic acid, phenoxy acetylene and dihydroisoquinoline in 1,4-dioxane was investigated in detail using the M06-L and M06-2X functionals. The barriers for the energetically more favorable pathway are 179.9, 85.4 and 82.7 kJ/mol. Ag⁺ activates and polarizes the C ≡ C triple bond of phenoxy acetylene, and stabilizes the intermediate of α-acyloxy enol ester. NCI analyses demonstrate that the π-π stacking does not facilitate the coupling of benzoic acid and phenoxy acetylene. Due to the fact that α-acyloxy enol ester is naturally highly polarized, the subsequent addition of α-acyloxy enol ester and dihydroisoquinoline can occur without the aid of Ag⁺. The atomic polar tensor (APT) charge and fuzzy bond order (FBO) analysis reveal the variation of the two C-N bonds.     

Soft Scorpionate Hydridotris(2-mercapto-1-methylimidazolyl) borate) Tungsten-Oxido and -Sulfido Complexes as Acetylene Hydratase Models

A series of W^IV alkyne complexes with the sulfur-rich ligand hydridotris(2-mercapto-1-methylimidazolyl) borate) (Tm^Me) are presented as bio-inspired models to elucidate the mechanism of the tungstoenzyme acetylene hydratase (AH). The mono- and/or bis-alkyne precursors were reacted with NaTm^Me and the resulting complexes [W(CO)(C₂R₂)(Tm^Me)Br] (R=H 1 , Me 2 ) oxidized to the target [WE(C₂R₂)(Tm^Me)Br] (E=O, R=H 4 , Me 5 ; E=S, R=H 6 , Me 7 ) using pyridine-N-oxide and methylthiirane. Halide abstraction with TlOTf in MeCN gave the cationic complexes [WE(C₂R₂)(MeCN)(Tm^Me)](OTf) (E=CO, R=H 10 , Me 11 ; E=O, R=H 12 , Me 13 ; E=S, R=H 14 , Me 15 ). Without MeCN, dinuclear complexes [W₂O(μ-O)(C₂Me₂)₂(Tm^Me)₂](OTf)₂ ( 8 ) and [W₂(μ-S)₂(C₂Me₂)(Tm^Me)₂](OTf)₂ ( 9 ) could be isolated showing distinct differences between the oxido and sulfido system with the latter exhibiting only one molecule of C₂Me₂. This provides evidence that a fine balance of the softness at W is important for acetylene coordination. Upon dissolving complex 8 in acetonitrile complex 13 is reconstituted in contrast to 9 . All complexes exhibit the desired stability toward water and the observed effective coordination of the scorpionate ligand avoids decomposition to disulfide, an often-occurring reaction in sulfur ligand chemistry. Hence, the data presented here point toward a mechanism with a direct coordination of acetylene in the active site and provide the basis for further model chemistry for acetylene hydratase.     

新型载铜碳纳米管催化剂的制备及其对乙炔氢氯化反应的催化活性

羧基碳纳米管与铜乙二胺溶液反应后于200℃焙烧制得新型载铜碳纳米管催化剂(Cu-CNTs)。考察了Cu-CNTs对乙炔氢氯化反应的催化活性。结果表明,Cu-CNTs相对于活性炭负载铜催化剂具有更好的催化活性,且更不易失活。     

Density Functional Theory Study of the Adsorption of C2H2 on the Cu/Pt(111) Bimetallic Surfaces

We applied periodic density-functional theory to investigate the adsorption of C2H2 on the Cu/Pt bimetallic and monometallic surfaces, including Cu-Pt-Pt and Pt-Cu-Pt representing the monolayer Cu on the Pt surface and subsurface Cu in the Pt surface, respectively. For the Pt(111) and Pt-Cu-Pt surfaces, C2H2 is preferentially a 3-fold "parallel-bridge" configuration, and a "μ-bridge" structure exists above the Cu(111) and Cu-Pt-Pt surfaces. The adsorption energy of C2H2 on these surfaces decreases in the order Pt(111) > Cu-Pt-Pt > Pt-Cu-Pt > Cu(111). The analysis of density of states, charge, and vibrational frequencies showed obviously weakening of the adsorbed C-C bond and high sp2 character on the carbon atom. Furthermore, when the top-layer compositions are equal, the nearer the EF d-band center is, the larger the C2H2 adsorption energy will be.     

担载镍催化剂上乙炔与甲酸甲酯加氢酯化合成丙烯酸甲酯:担载量和焙烧温度的影响(英文)

以ＮｉＯ担载量为０．０８ｗｔ％～１８．７ｗｔ％及焙烧温度为６２３ Ｋ～８７３ Ｋ的ＮｉＯ／Ａｌ２Ｏ３催化剂进行乙炔与甲酸甲酯的加氢酯化反应,并结合ＴＰＲ、ＸＰＳ、ＸＲＤ和ＢＥＴ技术对催化剂进行表征。催化剂在制备过程中,镍离子与载体氧化铝间的相互作用产生两种不同的镍物种,ＮｉＯ晶相和ＮｉＡｌ２Ｏ４类物种,它们间的比例随担载量及焙烧温度而异,因而表现出其对乙炔与甲酸甲酯加氢酯化不同的反应性能。实验结果表明,在７７３ Ｋ焙烧的１０Ｗｔ％ＮｉＯ／Ａｌ_２Ｏ_３最适合乙炔与甲酸甲酯的加氢酯化反应。     

Experimental 2CH excitation in acetylene-containing van der Waals complexes

Spectroscopic results are presented concerning the 2CH excitation around 1.5?µm in van der Waals complexes of acetylene (C₂H₂) with Ar, Kr, N₂, CO₂, N₂O and C₂H₂. Many are reviewed from the literature, with some updates. Previously unpublished results are also presented, concerning the mechanism of formation of C₂H₂–Ar in the supersonic jet, the assignment of new spectral structures in C₂H₂–N₂O, and the first observation of 2CH excitation in C₂H₂–Ne, C₂H₂–H₂O, C₂H₂–D₂O and (C₂H₂) _n . Lifetimes of these 2CH vibrationally excited dimers are discussed.     

Low-pressure line shape study of acetylene transitions in the ν 1 + ν 2 + ν 4 + ν 5 band over a range of temperatures

In this study we have retrieved the self-broadened widths, self-pressure-induced shifts, and Dicke narrowing coefficients for 20 R-branch transitions in the ν₁?+?ν₂?+?ν₄?+?ν₅ band of acetylene. The spectra were recorded using a three-channel diode laser spectrometer, a temperature-controlled cell of fixed length and a second, room temperature cell. The soft collision (Galatry) and hard collision (Rautian) profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift, and Dicke narrowing coefficients. We performed comparisons between our retrieved line parameters and published line parameters for acetylene transitions.