Structure of Perchlorato(2,5,8,11-Tetraazadodecane)Copper (II) Perchlorate Monohydrate

[Cu(C₈H₂₂N₄)]·(ClO₄)₂.H₂O, M_r= 454.80, orthorhombic C222₁, a = 15.481(5), b = 7.404(1), c = 14.827(3)Å, V = 1699.5(8)ų, Z = 4, D_x = 1.78 g/cm³, λ(MoKα) = 0.71073Å, μ = 16.5 cm^?1. F(000) = 940, T = 22°C, R = 6.86%, R_w = 7.66% for 820 observed reflections (I > 2.5σ (I)). The coordination number for the copper(II) ion is five, and the coordination geometry about copper(II) ion is a buckled square pyramid with the tetraamine equatorial and a perchlorate ion axial. The tetraamine is coordinated in a square-plannar manner with slight tetrahedral distortions. The four Cu-N distances span a very narrow range, 1.990(10) ?1.994(14)Å.     

Wire-shaped electrode of CdSe-sensitized ZnO nanowire arrays for photoelectrochemical hydrogen generation

We combined CdSe nanoparticles and ZnO nanowire arrays to demonstrate a wire-shaped electrode for photoelectrochemical hydrogen generation illuminated with AM 1.5 spectrum. An array of ZnO nanowires was grown vertically and radially outward from a Cu-wire mesh substrate. CdSe nanoparticles were attached to the surface of the orientated ZnO nanowires. Such wire-shaped electrode with radially outward orientated CdSe/ZnO nanowires provided improved electrolyte mass transport and minimized loss of incident photons. CdSe/ZnO nanowires were formed in all directions over the Cu wire, leading to low incident-light-angle dependence. For photoelectrochemical hydrogen generation under one-sun irradiation, the wire-shaped electrode device outperformed the planar-shaped electrode device by at least 30%.     

Synthesis and properties of poly(ether imide)s derived from 2,6-bis(3,4-dicarboxyphenoxy)naphthalene dianhydride and aromatic diamines

A new naphthalene unit-containing bis(ether anhydride), 2,6-bis(3,4-dicarboxyphenoxy)naphthalene dianhydride, was synthesized in three steps starting from the nucleophilic nitrodisplacement reaction of 2,6-dihydroxynaphthalene and 4-nitrophthalonitrile in N,N-dimethylformamide (DMF) solution in the presence of potassium carbonate, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). High-molar-mass aromatic poly(ether imide)s were prepared using a conventional two-step polymerization process from the bis(ether anhydride) and various aromatic diamines. The intermediate poly(ether amic acid)s had inherent viscosities of 0.65–2.03 dL/g. The films of poly(ether imide)s derived from two rigid diamines, i.e. p-phenylenediamine and benzidine, crystallized during the thermal imidization process. The other poly(ether imide)s belonged to amorphous materials and could be fabricated into transparent, flexible, and tough films. These aromatic poly(ether imide) films had yield strengths of 104–131 MPa, tensile strengths of 102–153 MPa, elongation to break of 8–87%, and initial moduli of 1.6–3.2 GPa. The glass transition temperatures (T_g's) of poly(ether imide)s were recorded in the range of 220–277°C depending on the nature of the diamine moiety. All polymers were stable up to 500°C, with 10% weight loss being recorded above 550°C in both air and nitrogen atmospheres. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1657–1665, 1998     

Electroactive aromatic polyamides and polyimides with adamantylphenoxy-substituted triphenylamine units

A new triphenylamine-containing aromatic diamine monomer, 4-[4-(1-adamantyl)phenoxy]-4′,4″-diaminotriphenylamine, was synthesized from cesium fluoride-mediated N,N-diarylation of 4-(1-adamantyl)-4′-aminodiphenyl ether with 4-fluoronitrobenzene and subsequent reduction of the resultant dinitro compound. Novel electroactive aromatic polyamides and polyimides with adamantylphenoxy-substituted triphenylamine moieties were prepared from the newly synthesized diamine monomer with aromatic dicarboxylic acids and tetracarboxylic dianhydrides, respectively. All the resulting polymers were amorphous and most of them were readily soluble in polar solvents such as N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc) and could be solution-cast into transparent and strong films with good mechanical properties. These polymers exhibited glass-transition temperatures between 254 and 310 °C, and they were fairly stable up to a temperature above 450 °C for the polyamides and above 500 °C for the polyimides. These polymers exhibited strong UV-vis absorption maxima at 293-346 nm in solution, and the photoluminescence spectra of polyamides showed maximum bands around 408-452 nm in the blue region. Cyclic voltammograms of the polyamide and polyimide films on an indium-tin oxide (ITO)-coated glass substrate exhibited one pair of reversible redox couples at half-wave oxidation potentials (E_1/2) around 0.83-0.86 V and 1.12-1.13 V, respectively, versus Ag/AgCl in an acetonitrile solution. All the polymer films revealed good electrochemical and electrochromic stability by repeatedly switching electrode voltages between 0.0 V and 1.1-1.4 V, with coloration change from the pale yellowish neutral state to the green or blue oxidized state.     

硼酰化钴中硼的快速测定

硼酰化钴中硼的测定采用EDTA作为钴的络合掩蔽剂,消除了钴对测定硼的影响。同时改用溴甲酚绿-甲基红-酚酞三元混合指示剂作为测定硼的指示剂,使滴定终点灵敏、准确。建立了一种测定硼酰化钴中硼含量的简便、快速的分析方法。     

Preparation and properties of aromatic polyamides from 1,4-bis(p-carboxyphenoxy)naphthyl and aromatic diamines

A new aromatic dicarboxylic acid, 1,4-bis (p-carboxyphenoxy)naphthyl ( 3 ), was synthesized by the reaction of p-fluorobenzonitrile with 1,4-naphthalenediol, followed by hydrolysis. Aromatic polyamides having inherent viscosities of 1.27–2.22 dL/g were prepared by the triphenyl phosphite activated polycondensation of diacid 3 with various aromatic diamines. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including N,N-dimethyl-acetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and m-cresol. Transparent, tough, and flexible films of these polymers could be cast from the DMAc or NMP solutions. The cast films had tensile strengths ranging from 64–104 MPa, elongations-at-break from 6 to 10%, and initial moduli from 1.52 to 2.14 GPa. These polyamides had glass transition temperatures in the range of 195 to 240°C. Almost all polymers were thermally stable up to 400°C, with 10% weight loss being recorded above 480°C in air and nitrogen atmospheres. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2273–2280, 1997     

Synthesis and Evaluation of α-Methylidene-γ-butyrolactone bearing flavone and xanthone moieties

In a search for inhibitors of platelet aggregation, a number of α-methylidene-γ-butyrolactones 5 and 6 bearing flavone or xanthone moieties, respectively, were synthesized and evaluated for their antiplatelet activity against thrombin(Thr)-, arachidonic-acid(AA)-, collagen(Col)?, and platelet-activating-factor(PAF)-induced aggregation in washed rabbit platelets. These compounds were synthesized from 7-hydroxyflavone ( 1 ) or 3-hydroxyxanthone ( 2 ) via O-alkylation (→ 3 and 4 , resp.) and Reformatsky-type condensation (Scheme). Most of the flavone-containing α-methylidene-γ-butyrolactones 5a – d showed potent antiplatelet effects on AA- and Col-induced aggregation, while xanthone derivatives 6c – e were found to have the same pharmacological profile than aspirin in which only AA-induced aggregation was inhibited (Table 1). However, 6c – e were approximately three to ten times more potent than aspirin (Table 2). For the vasorelaxing effects, 5a was the only compound which exhibited significant inhibitory activity on the high-K⁺ medium, Ca²⁺-induced vasoconstriction (Table3). Both 5a and 6a , with an aliphatic Me substituent at C(γ) of the lactone, were active against norepinephrine-induced phasic and tonic constrictions while their γ-aryl-substituted counterparts 5b – f and 6b – f were inactive.     

Synthesis and structural studies of hydrophilic mesocyclic trithioethers

The functionalized mesocyclic trithioethers, 1,4,7-trithiacyclodecane-9,9-dimethanol (10S3-diMeOH), 9 -methyl-1, 4, 7 - trithiacyclodecane - 9 -carboxylic acid (Me-10S3-acid), 1,4,7-trithiacycloundecane-9,10-diol (dihydroxy-11S3), 1,5,9-trithiacyclododecane-3,3-dimethanol (12S3-diMeOH), 3-methyl-1,5,9-trithiacyclododecane-3-carboxylic acid (Me-12S3-acid), and 1 , 5 , 9 - trit hiacyclo tride cane -11 , 12 - diol ( dihydroxy - 13S3), have been synthesized using the cesium dithiolate technique. The single-crystal X-ray structure has been determined for 3-methyl-1,5,9-trithiacyclododecane-3-carboxylic acid. The compound crystallizes in the monoclinic space group P2₁/n, with a = 9.513(2) Å, b = 5.706(1) Å, c = 25.70(1) Å, β = 96.50(1)°, Z = 4, and R = 0.075. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:123–128, 1998     

Atomic structures of silicon and metal surfaces; pulsed-laser tof atom-probe and field ion microscopy

The atomic structure of a solid surface can be imaged with the field ion microscope and the chemical species of surface atoms can be identified by the time-of-flight atom-probe. By combining a pulsed-laser technique to field ion microscopy, atomic processes in surface reconstruction and growth of thin films can be studied with a resolution of 2.5 Å, and in time steps of a few nanoseconds. The mass resolution and material applicability of a pulsed-laser time-of-flight atom-probe are greatly improved. Thus materials of poor conductivity such as high purity silicon can be analyzed with excellent mass resolution. It is also ionion energy analyzer with an accuracy and resolution of 2 parts per 100 000 and an ion reaction and dissociation time analyzer of 20 fs time resolution. Some recent studies with these techniques such as (1) surface reconstruction of Pt and Ir(001) and (110) surfaces, (2) observation of well ordered and atomically resolved images of pure silicon surfaces and surface reconstruction of many surfaces of silicon, and (3) formation of multiple charge cluster ions and dissociation of compound ions by atomic tunneling in an electric field etc., will be briefly described. We want to emphasize that recent studies of Si and metal surfaces are concerned with atomic structures of thermally equilibrated surfaces, and not with field evaporated surfaces as in earlier studies.     

Ranking fuzzy numbers with integral value

Ranking fuzzy numbers is important in decision making. Since very often the alternatives are evaluated by fuzzy numbers in a vague environment, a comparison between these fuzzy numbers is indeed a comparison between alternatives. This paper proposes a method of ranking fuzzy numbers with integral value. The method, which is independent of the type of membership functions used and the normality of the functions, can rank more than two fuzzy numbers simultaneously. It is relatively simple in computation, especially in ranking triangular and trapezoidal fuzzy numbers. Further, an index of optimism is used to reflect the decision maker's optimistic attitude. Discussion on comparative advantages is included.