Two Mn(2)(II)Ln(4)(III) (Ln = Gd, Eu) hexanuclear compounds of p-tert-butylsulfinylcalix[4]arene

Two 3d-4f heterometallic compounds of p-tert-butylsulfinylcalix[4] arene were synthesized by the solvothermal method and characterized by some hinged double-dumbbell-like subunits in which two perpendicular dumbbell entities were constructed by an in-between isosceles triangle Mn(II)Ln(2)(III), and two tail-to-tail calixarene molecules, and hinged by the lanthanide-sulfinyl group bonding. The magnetic properties of the title compounds were examined.

A ternary supramolecular compound of p-sulfonatocalix[8]arene with 1D channels

A ternary supramolecular complex of [Ni(bipy)(2)(H2O)](4)(C8AS)center dot 17.6(H2O) (bipy=4,4'-dimethyl-2,2'-bipyridine and C8AS = p-sulfonatocalix[8]arene) has been synthesized by a hydrothermal method and characterized by FT-IR spectroscopy, TG-DTA analysis and single crystal X-ray diffraction. In the structure. the water-soluble p-sulfonatocalix[8]arene molecule adopts a double partial cone conformation and is coordinated by four nickel atoms each of which is bonded by two 4,4'-dimethyl-2,2'-bipyridine molecules and one water molecule at the same time. The tetranuclear Subunits are stacked into an extended 3D structure with 1D water-filled channels via hydrogen bonds and C-H center dot center dot center dot pi interactions.

Assembly of Seven Supramolecular Compounds with p-Sulfonatocalix[6]arene

Seven supramolecular compounds comprising p-sulfonatocalix[6]arene and transition metals, {[Cu(Imz)-(phen)(H2O)](4)[C6AS]}center dot 10H(2)O (1), {[Cu(Imz)(2)(phen)](2)[Cu(Imz)(phen)(H2O)(2)](2)[C6AS]}center dot 13.3H(2)O (2), {[M(phen)(2)(H2O)]-[(M(phen)(2)](2)[C6AS]}center dot nH(2)O (3 and 4) (3: M = Co and n = 29.6; 4: M = Zn and n = 29.9), {[Cu(phen)(2)](4)[C6AS]}(2)center dot 13H(2)O (5), [H3O](2)[Co(phen)(3)](2)[C6AS]center dot 10.7H(2)O(6), and [Cu(phen)(2)(H2O)](2){[Cu(phen)(2)](2)[C6AS]}center dot 8H(2)O(7)(phen = 1,10-phenanthroline, C6AS = p-sulfonatocalix[6]arene, Imz = imidazole), have been synthesized by a hydrothermal method and structurally characterized by IR spectroscopy, thermogravimetric-differential thermal analysis (TG-DTA), and single crystal X-ray diffraction.

1,2,3,4-Alternate double cone conformational extreme in the supramolecular assemblies of p-sulfonatocalix[8]arene

Two supramolecular assemblies of p-sulfonato-calix[8]arene were stacked by some infinite 1D 'molecular capsule' chains in which the calixarenes adopt an unprecedented 1,2,3,4-alternate double cone conformation.

P(AM/AMPS/NVP)降失水剂合成与耐温性能研究

采用自由基水溶液聚合法成功制备了丙烯酰胺(AM)/2-甲基-2-丙烯酰胺基丙磺酸(AMPS)/N-乙烯基吡咯烷酮(NVP)三元共聚耐温型降滤失剂,通过红外(FTIR)光谱和核磁C谱表征了共聚物的结构,通过元素分析考察了共聚物组成。热失重(TGA)表明,P(AM/AMPS/NVP)耐温性优于P(AM/AMPS)和P(AM),通过对三元共聚物的抗高温性和降失水性的研究,表明P(AM/AMPS/NVP)具有良好的耐温降滤失性能。

Cyclization of citronellal to p-menthane-3,8-diols in water and carbon dioxide

A clean process has been developed for the synthesis of p-menthane-3,8-diols from cyclization of citronellal in CO2-H2O medium without any additives. With the addition of CO2, the reaction rate could be enhanced about 6 times for the cyclization of citronellal in H2O, because CO2 dissolved into water and formed carbonic acid inducing an increase of the acidity. Although, the reaction conversion in CO2-H2O is slightly lower compared to that obtained with sulfuric acid as catalyst, CO2-H2O could replace the sulfuric acid at a relative higher reaction temperature. The reaction kinetics studies showed that the hydration of isopulegols to p-menthane-3,8-diols is a reversible reaction. The equilibrium constant and the maximum equilibrium yield obtained in CO2-H2O at a range of CO2 pressures are similar to that with sulfuric acid catalyst.

From Tunneling to Hopping: A Comprehensive Investigation of Charge Transport Mechanism in Molecular Junctions Based on Oligo(p-phenylene ethynylene)s

The charge transport mechanism of oligo(p-phenylene ethynylene)s with lengths ranging from 0.98 to 5.11 nm was investigated using modified scanning tunneling microscopy break junction and conducting probe atomic force microscopy methods. The methods were based on observing the length dependence of molecular resistance at single molecule level and the current-voltage characteristics in a wide length distribution. An intrinsic transition from tunneling to hopping charge transport mechanism was observed near 2.75 nm. A new transitional zone was observed in the long length molecular wires compared to short ones. This was not a simple transition between direct tunneling and field emission, which may provide new insights into transport mechanism investigations. Theoretical calculations provided an essential explanation for these phenomena in terms of molecular electronic structures.

Polymerization of 1,3-butadiene with VO(P-204)(2) and VO(P-507)(2) activated by alkylaluminum

The oxovanadium phosphonates (VO(P-204)(2) and VO(P-507)(2)) activated by various alkylaluminums (AlR3, R = Et, i-Bu, n-Oct; HAIR(2), R = Et, i-Bu) were examined in butadiene (Bd) polymerization. Both VO(P-204)(2) and VO(P-507)(2) showed higher activity than those of classical vanadium-based catalysts (e.g. VOCl3, V(acac)(3)). Among the examined catalysts, the VO(P-204)(2)/Al(Oct)(3) system (I) revealed the highest catalytic activity, giving the poly(Bd) bearing M-n of 3.76 x 10(4) g/mol, and M-w/M-n ratio of 2.9, when the [Al]/[V] molar ratio was 4.0 at 40 degrees C. The polymerization rate for I is of the first order with respect to the concentration of monomer. High thermal stability of I was found, since a fairly good catalytic activity was achieved even at 70 degrees C (polymer yield > 33%); the M-n value and M-w/M-n, ratio were independent of polymerization temperature in the range of 40-70 degrees C. By IR and DSC, the poly(Bd)s obtained had high 1,2-unit content (> 65%) with atactic configuration. The 1,2-unit content of the polymers obtained by I was nearly unchanged, regardless of variation of reaction conditions, i.e. [Al]/[V], ageing time, and reaction temperature, indicating the high stability of stereospecificity of the active sites.