Synthesis, Crystal Structure, Properties and Thermoanalysis of Complexes of Cu（Ⅱ） and Ni（Ⅱ） with Taurine-5-chlorosalicylaldelyde Schiff Base

The reactions of transition metal salts with taurine 5‐chlorosalicylaldelyde Schiff base gave two complexes [Ni(TCSSB)(H₂O)₃].H₂O (1) and [Cu(TCSSB)(H₂O)₂]₂[Cu(TCSSB)₂].6H₂O (2) (TCSSB=taurine‐5‐chlorosalicylaldelyde Schiff base), which were characterized by elemental analysis and X‐ray diffraction analysis. The complex 1 crystallized in monoclinic system with space group P2 ₁/c, and a=1.4816(2) nm, b=1.3953(2) nm, c= 0.7466(1) nm, β= 100.499(3)°, V=1.5176(4) nm³, Z=4, and an infinite 3‐D network structure was formed by hydrogen bonds among sulfo group, crystal water and coordinated water. Complex 2 crystallized in triclinic system with space group P1 , with the cell parameters: a = 0.6413(2) nm, b= 1.4596(3) nm, c= 1.6188(4) nm, a= 102.473(5)°, β= 98.979(4)°, γ=101.739°, V=1.4165(6) nm³, Z=1. The coordination environment between Cu(1) and Cu(2) is different. Cu(1) is slightly distorted square pyramidal while Cu(2) is distorted square‐plane. The complex 1 is mononuclear while the complex 2 is made up of two coordinated subunits, namely [Cu(TCSSB)₂] and [CU(TCSSB)(H₂O)₂]₂. Besides that the TG‐DTG of the complex 1 was analyzed, the thermal decomposition reaction of the complex was studied under a non‐isothermal condition by TG‐DTG. The TG and DTG curves indicate that the complex was decomposed in three stages: .     

Understanding the conformational dependence of spin-spin coupling constants: through-bond and through-space J(31P,31P) coupling in tetraphosphane-1,4-diides [M(L)x]2[P4R4

The characteristic dependence of J(31P,31P) spin-spin coupling constants of alkali metal tetraphosphane-1,4-diides on structure and composition has been analyzed by density functional methods. The computations confirm that the structure of the contact ion pairs is conserved in solution. Calculations on model systems M2P4H4, on naked P4H4(2-) anions, and on models including point charges, show that the role of the cations is mainly structural and to a smaller extent electrostatic. Three of the four J(P,P) coupling constants depend characteristically on the conformation of the anion, which in turn is determined by the substituents R and by cation-anion interactions. Several couplings exhibit a large through-space component and are thus strongly dependent on the relative orientation of nonbonding electron pairs on the phosphorus atoms involved. This is shown by visualization of coupling pathways using the recently introduced coupling energy density (CED), in combination with the electron localization function (ELF).     

Model Construction for the A–B–C Ring System of Lysergic Acid via Vilsmeier–Haack‐Type Cyclization of 1H‐Indole‐4‐propanoic Acid Derivatives

Vilsmeier–Haack‐type cyclization of 1H‐indole‐4‐propanoic acid derivatives was examined as model construction for the A–B–C ring system of lysergic acid ( 1 ). Smooth cyclization from the 4 position of 1H‐indole to the 3 position was achieved by Vilsmeier–Haack reaction in the presence of K₂CO₃ in MeCN, and the best substrate was found to be the N,N‐dimethylcarboxamide 9 (Table 1). The modified method can be successfully applied to an α‐amino acid derivative protected with an N‐acetyl function, i.e., to 27 (Table 2); however, loss of optical purity was observed in the cyclization when a chiral substrate (S)‐ 27 was used (Scheme 5). On the other hand, the intramolecular Pummerer reaction of the corresponding sulfoxide 20 afforded an S‐containing tricyclic system 22 , which was formed by a cyclization to the 5 position (Scheme 3).     

Four New Nortriterpenoids from Phlomis umbrosa

Four new 28‐noroleanane‐derived spirocyclic triterpenoids, compounds 1 – 4 , were isolated from the rhizomes of Phlomis umbrosa. Their structures were elucidated on the basis of 1D‐ and 2D‐NMR analyses, in combination with high‐resolution MS experiments.     

Highly Regioselective Sequential 1,1‐Dihydrosilylation of Terminal Aliphatic Alkynes with Primary Silanes

A regioselective double 1,1‐hydrosilylation of terminal aliphatic alkynes with primary silanes catalyzed by one cobalt catalyst has been developed. gem‐Bis(dihydrosilyl)alkanes containing four silicon‐hydrogen bonds are efficiently constructed in an atom‐economical manner. Tolerated substrates include simplest alkyne‐ethyne, a complicated drug derivative and various functionalized terminal aliphatic alkynes. Asymmetric approach using two catalysts is achieved with excellent enantioselectivities to access corresponding chiral products. The transformations of Si—H bonds into Si—C, Si—O, and Si—F bonds and the synthesis of enantioriched α‐hydroxysilane show synthetic utility.     

Radiation synthesis of n-vinyl 2-pyrrolidone/acrylonitrile interpenetrating polymer networks and their use in uranium recovery from aqueous systems

Interpenetrating Polymer Networks (IPNs) based on Poly n-vinyl 2-pyrrolidone (PVP) and Acrylonitrile (AN) were prepared by irradiating PVP solutions prepared in AN. PVP/AN mixtures were irradiated by ⁶⁰Co-γ rays at room temperature at a dose rate of 0.5 kGy/hour. IPNs were characterized by using FT-IR and Thermal Analysis techniques. The chelating adsorbents containing amidoxime groups were prepared by the reaction of these IPNs with hydroxylamine in aqueous NaOH solution at 50°C. These amidoxime containing adsorbents were used in adsorption studies for the recovery of uranium from aqueous systems. The adsorption capacity of an IPN with equivolume fraction of PVP and amidoximated PAN was found to be 750mg UO₂²⁺/g dry amidoximated IPN.     

不对称烷氧基取代聚对苯乙炔的合成及电致发光性能

利用强碱诱导的去卤缩合聚合法，合成了不对称烷氧基取代的聚（２－甲氧基－５－十二烷氧基－１，４－对苯乙炔）（ＰＭＤＰＶ）．其溶解性和成膜性能优于对称取代的聚（２，５－双十二烷氧基－１，４－对苯乙炔）．以ＰＭＤＰＶ为发光层质的聚合物电致发光器件，其发光峰值波长为６０５ｎｍ．并用ＩＲ、ＵＶ－Ｖｉｓ、ＴＧＡ、１ＨＮＭＲ、ＧＰＣ等对所合成的聚合物进行了表征．     

Theoretical studies on the smallest fullerene: from monomer to oligomers and solid States

Hybrid B3LYP and density-functional-based tight-binding (DFTB) computations on the solid-state structures and electronic properties of the C(20) fullerene monomer and oligomers are reported. C(20) cages with C(2), C(2h), C(i), D(3d), and D(2h) symmetries have similar energies and geometries. Release of the very high C(20) strain is, in theory, responsible for the ready oligomerization and the formation of different solid phases. Open [2+2] bonding is preferred both in the oligomers and in the infinite one-dimensional solids; the latter may exhibit metallic character. Two types of three-dimensional solids, the open [2+2] simple cubic and the body-centered cubic (bcc) forms, are proposed. The energy of the latter is lower due to the better oligomer bonding. The open [2+2] simple cubic solid should be a conductor, whereas the bcc solids are insulators. The most stable three-dimensional solid-state structure, an anisotropically compressed form of the bcc solid, has a HOMO-LUMO gap of approximately 2 eV and a larger binding energy than that of the proposed C(36) solid.     

Shape-controlled synthesis of metal nanostructures: the case of silver

The concept of shape-controlled synthesis is discussed by investigating the growth mechanisms for silver nanocubes, nanowires, and nanospheres produced through a polymer-mediated polyol process. Experimental parameters, such as the concentration of AgNO(3) (the precursor to silver), the molar ratio between poly(vinylpyrrolidone) (PVP, the capping agent) and AgNO(3), and the strength of chemical interaction between PVP and various crystallographic planes of silver, were found to determine the crystallinity of seeds (e.g., single crystal versus decahedral multiply twinned particles). In turn, the crystallinity of a seed and the extent of the PVP coverage on the seed were both instrumental in controlling the morphology of final product. The ability to generate silver nanostructures with well-defined morphologies provides a great opportunity to experimentally and systematically study the relationship between their properties and geometric shapes.