Studies on the identification and syntheses of insect pheromones XXI stereoselective synthesis of all the possible optical isomers of the mosquito oviposition attractant pheromone

All the four optical isomers of the oviposition attractant pheromone of the mosquito $\text{Gulex pipiens fatigans}$ were synthesized via Sharpless asymmetric epoxidation.     

Determination of metal additives and bromine in recycled thermoplasts from electronic waste by TXRF analysis

A new method for analysis of metal additives in recycled thermoplasts from electronic waste was developed, based on dissolving the samples in an organic solvent and subsequent analysis of the corresponding solutions or suspensions by total-reflection X-ray fluorescence spectroscopy (TXRF). The procedure proved to be considerably less time consuming than the conventional digestion of the polymer matrix. Additives containing Ti, Zn, Br, Cd, Sn, Sb, and Pb were analyzed in a hundred randomly selected samples from recycling, which provided an overview of the range of elemental concentrations in thermoplasts utilized for consumer electronics. The results were validated independently by instrumental neutron activation analysis (INAA), subsequent regression analysis confirmed the trueness of the chosen approach.     

H2/CO2 separations in multicomponent metal-adeninate MOFs with multiple chemically distinct pore environments

Metal–organic frameworks constructed from multiple (≥3) components often exhibit dramatically increased structural complexity compared to their 2 component (1 metal, 1 linker) counterparts, such as multiple chemically unique pore environments and a plurality of diverse molecular diffusion pathways. This inherent complexity can be advantageous for gas separation applications. Here, we report two isoreticular multicomponent MOFs, bMOF-200 (4 components; Cu, Zn, adeninate, pyrazolate) and bMOF-201 (3 components; Zn, adeninate, pyrazolate). We describe their structures, which contain 3 unique interconnected pore environments, and we use Kohn–Sham density functional theory (DFT) along with the climbing image nudged elastic band (CI-NEB) method to predict potential H₂/CO₂ separation ability of bMOF-200. We examine the H₂/CO₂ separation performance using both column breakthrough and membrane permeation studies. bMOF-200 membranes exhibit a H₂/CO₂ separation factor of 7.9. The pore space of bMOF-201 is significantly different than bMOF-200, and one molecular diffusion pathway is occluded by coordinating charge-balancing formate and acetate anions. A consequence of this structural difference is reduced permeability to both H₂ and CO₂ and a significantly improved H₂/CO₂ separation factor of 22.2 compared to bMOF-200, which makes bMOF-201 membranes competitive with some of the best performing MOF membranes in terms of H₂/CO₂ separations.

Tailorable multicomponent MOFs and MOF membranes for efficient H₂/CO₂ separation.     

Surface-enhanced Raman scattering and polarized photoluminescence from catalytically grown CdSe nanobelts and sheets

We have successfully fabricated single-crystalline CdSe nanowires, nanobelts, and sheets by a chemical vapor deposition (CVD) method assisted with laser ablation. The synthesized CdSe nanostructures have hexagonal wurtzite phase as characterized by X-ray diffraction (XRD). CdSe nanobelts can range in length from several tens to a hundred micrometers, in thickness from 40 to 70 nm, and a tapered width which is approximately 3 microm at one end and tapers off to approximately 100 nm at a catalytic gold particle. Both selected area electron diffraction (SAED) and high-resolution transmission electron microscopic (HRTEM) measurements show that the single-crystalline hexagonal belts and sheets grew along the [0.1-1.0] direction with side surface of +/-(0 0 0 1) and top surface of +/-(2 -1 -1 0). While the growth mechanism of nanobelts complies with a combination of vapor-liquid-solid (VLS) and vapor-solid (VS) processes, the formation of sheets is primarily based on the VS mechanism. For comparison, the phonon modes of CdSe nanobelts and bulk powder have been measured by surface-enhanced Raman scattering (SERS) and normal Raman scattering (NRS) spectroscopies with off- and near-resonant excitations. A blue-shift of 2.4 cm(-1) for the longitudinal optical (LO) phonon of CdSe nanobelts, relative to bulk CdSe, is attributed to a lattice contraction in the belt structure, which is confirmed by the XRD measurement. Room-temperature microphotoluminescence (PL) at approximately 1.74 eV from single CdSe nanobelts shows a 3-fold enhancement compared to that from bulk CdSe powder and displays a partial polarization dependence of emission angles.     

新型混价铜配合物[CuⅠCuⅡ(Ophen)2Cl]·H2O(HOphen=2-羟基-1,10-邻菲咯啉)的水热合成和晶体结构

报道了一种新型混价铜配合物[CuⅠCuⅡ(Ophen)2Cl]·H2O(HOphen=2-羟基-1,10′-邻菲咯啉)的水热合成和晶体结构.该化合物属于三斜晶系,P1空间群,a=0.91667(18)nm,b=1.0546(2)nm,c=1.1705(2)nm,α=80.50(3)°,β=80.56(3)°,γ=66.87(3)°,V=1.0202(3)nm3,Z=2,Dc=1.872Mg/m3,R1=0.0508,(wR2)=0.1481.标题化合物由一种新型的双核铜配合物和一个结晶水组成.邻菲咯啉在水热反应中发生羟基化,形成新型的羟基化邻菲咯啉.两个这样的配合物通过Cu…Cu间的范德华力相互作用形成二聚体.二聚体之间通过Ophen基团的π-π堆积以及C—H…Cl弱相互作用构筑成三维超分子网络.水分子处于网络的孔穴中.该化合物为邻菲咯啉的羟基化提供又一个新的范例.     

CH4-nFn(n=1～3)与CH3氢抽提反应微观动力学的理论研究

采用量子化学的QCISD(T)/6-311 G(d,p)//BHandHLYP/6-311G(d,p)方法研究了氟代甲烷CH4-nFn(n=1~3)与CH3自由基氢抽提反应的微观动力学性质.并利用Polyrate程序分别计算了3个反应在200~3000K范围内的速率常数.计算结果表明,R1a,R2a和R3三个反应路径的反应能量分别为-12.7,-9.5和11.8kJ/mol,相应的能垒依次为67.0,62.2和67.5kJ/mol.在437K时,kCVT/SCT分别为6.72×10-19,8.01×10-18和8.82×10-20cm3/(molecule.s).计算结果还表明,在低温段反应的量子隧道效应显著,在计算温度范围内变分效应对反应速率常数的影响可以忽略.     

紫外线激活氚原子—制备氚标记单磷酸阿糖腺苷的研究

本文采用紫外线激活氚原子的方法,进行氚-氢同位素交换反应,制得氚标记单磷酸阿糖腺苷(9—~3H—mparaA)。产品的纯度是层析纯;放射性比活度16GBq.m mol~(-1);放射化学纯度92.0%。本法的优点是:交换反应温和、反应时间较短、不易破坏生物活性、引起的副产物少、产品分离和纯化较方便。     

Synthesis, dual fluorescence, and fluoroionophoric behavior of dipyridylaminomethylstilbenes

The synthesis, dual fluorescence, and fluoroionophoric behavior of two donor-sigma spacer-acceptor (D-s-A) compounds, trans-4-(N,N-bis(2-pyridyl)amino)methylstilbene (1H) and trans-4-(N,N-bis(2-pyridyl)amino)methyl-4'-cyanostilbene (1CN), are reported and compared to that of trans-4-(N,N-bis(2-pyridyl)amino)methyl-4'-(N,N-dimethylamino)stilbene (1DPA). To gain insights into the dual fluorescence properties for 1H and 1CN in polar but not in nonpolar solvents, model compounds resulting from a replacement of the stilbene group by alkyl (2R) or xylyl (2X) groups or from a replacement of the dipyridylamino (dpa) group by dianisoleamino (3AA), diethylamino (3EE), methylanilino (3MP), or diphenylamino (3PP) groups also have been investigated. In addition to 1H and 1CN, all four compounds of 3 display dual fluorescence. The locally excited (LE) fluorescence mainly results from the stilbene group and the ICT fluorescence from the through-bond interactions between the amino donor and the stilbene acceptors. In the presence of transition metal ions such as Zn(II), Ni(II), Cu(II), and Cd(II), the ICT processes are switched from dpa (D) --> stilbene (A) in 1H and 1CN to stilbene (D) --> dpa/metal ion (A) in their complexes. Whereas the ICT states for the complexes are generally nonfluorescent, an exception was found for the case of 1H/Zn(II). As a result, substituent-dependent fluoroionophoric behavior has been demonstrated by 1H, 1CN, and 1DPA in response to Zn(II).     

Electrocatalytic Oxidation of Dopamine by Ferrocene in Lipid Film Cast on a Glassy Carbon Electrode

ＩｎｔｒｏｄｕｃｔｉｏｎＤＡｉｓｏｎｅｏｆｅｓｓｅｎｔｉａｌｐａｒｔｉｃｉｐａｎｔｓｉｎｔｈｅｎｅｕｒｏ ｔｒａｎｓｍｉｓｓｉｏｎｐｒｏｃｅｓｓｉｎｍａｍｍａｌｉａｎｃｅｎｔｒａｌｎｅｒｖｏｕｓｓｙｓ ｔｅｍ .ＡｌｏｓｓｏｆＤＡ ｃｏｎｔａｉｎｉｎｇｎｅｕｒｏｎｓｍａｙｒｅｓｕｌｔｉｎｓｏｍｅｓｅｒｉｏｕｓｄｉｓｅａｓｅｓｕｃｈａｓＰａｒｋｉｎｓｏｎｉｓｍ .1Ｓｉｎｃｅｉｔｓｄｉｓｃｏｖ ｅｒｙｉｎｔｈｅ 195 0ｓ ,ＤＡｈａｓｂｅｅｎｏｆｉｎｔｅｒｅｓｔｔｏｎｅｕｒｏｓｃｉｅｎ ｔｉｓｔｓａｎｄｃｈｅｍ…     

New pavine N-oxide alkaloids from the stem bark of Cryptocarya chinensis Hemsl

Three new pavine N-oxide alkaloids, (-)-isocaryachine-N-oxide B, (+)-caryachine-N-oxide, (-)-caryachine-N-oxide, and a new isoquinoline alkaloid, 6,7-methylenedioxy-N-methylisoquinoline together with 11 known alkaloids were isolated and characterized from the stem bark of Cryptocarya chinensis. The structures of the isolated compounds were determined by spectral methods. The stereochemistry of pavine-N-oxide alkaloids is also discussed.