Lewis base stabilized phosphanylborane

The abstraction of the Lewis acid from [W(CO)(5)(PH(2)BH(2)NMe(3))] (1) by an excess of P(OMe(3))(3) leads to the quantitative formation of the first Lewis base stabilized monomeric parent compound of phosphanylborane [H(2)PBH(2)NMe(3)] 2. Density functional theory (DFT) calculations have shown a low energetic difference between the crystallographically determined antiperiplanar arrangement of the lone pair and the trimethylamine group relative to the P-B core and the synperiplanar conformation. Subsequent reactions with the main-group Lewis acid BH(3) as well as with an [Fe(CO)(4)] unit as a transition-metal Lewis acid led to the formation of [(BH(3))PH(2)BH(2)NMe(3)] (3), containing a central H(3)B-PH(2)-BH(2) unit, and [Fe(CO)(4)(PH(2)BH(2)NMe(3))] (4), respectively. In oxidation processes with O(2), Me(3)NO, elemental sulfur, and selenium, the boranylphosphine chalcogenides [H(2)P(Q)BH(2)NMe(3)] (Q = S 5 b; Se 5 c) as well as the novel boranyl phosphonic acid [(HO)(2)P(O)BH(2)NMe(3)] (6 a) are formed. All products have been characterized by spectroscopic as well as by single-crystal X-ray structure analysis.     

Expanding the world of endohedral fullerenes--the Tm3N@C2n (39< or =n< or =43) clusterfullerene family

A new family of endohedral fullerenes, based on an encaged trithulium nitride (Tm(3)N) cluster, was synthesised, isolated and characterised by HPLC, mass spectrometry, and visible-NIR and FTIR spectroscopy. Tm(3)N clusterfullerenes with cages as small as C(76) and as large as C(88) were prepared and six of them were isolated. Tm(3)N@C(78) is a small clusterfullerene. The two isomers of Tm(3)N@C(80) (I and II) were the most abundant structures in the fullerene soot. Tm(3)N@C(82), Tm(3)N@C(84), and Tm(3)N@C(86) represent a new series of higher clusterfullerenes. All six isolated Tm(3)N clusterfullerenes were classified as large energy-gap structures with optical energy gaps between approximately 1.2 and approximately 1.75 eV. Tm(3)N@C(80) (I) and Tm(3)N@C(80) (II) were assigned to the C(80) cages C(80):7 (I(h)) and C(80):6 (D(5h)). For Tm(3)N@C(78), the analysis pointed to an elliptical carbon cage with C(78):1 (D(3)) or C(78):4 (D(3h)) being the probable structures.     

Neutral helium compounds: theoretical evidence for a large class of polynuclear complexes

Ab initio calculations at the MP2 and CCSD(T) levels of theory disclose the conceivable existence of neutral complexes containing up to four helium atoms. These species are formally obtained by replacing the hydrogen atoms of parent molecules such as CH(4), SiH(4), NH(3), PH(3), H(2)O, H(2)S, C(2)H(2), C(2)H(4), and C(6)H(6) with -NBeHe moieties, which behave as monovalent functional groups containing helium. The geometries and vibrational frequencies of these M(NBeHe)(n) (n>1; M=central moiety) polyhelium complexes have been investigated at the MP2(full)/6-31G(d) level of theory, and their stability with respect to the loss of helium atom(s) has been evaluated by means of single-point calculations at the CCSD(T)/6-311G(d,p) level of theory. Molecules such as H(n)C(NBeHe)(4-n) and H(n)Si(NBeHe)(4-n) (n=0-3), C(2)(NBeHe)(2), and ortho-, meta-, and para-C(6)H(4)(NBeHe)(2) were invariably characterized as energy minima, and were found to be stable with respect to the loss of helium atom(s) by approximately 4-5 kcal mol(-1). On the other hand, species such as C(2)(NBeHe)(4) and C(6)(NBeHe)(6) were characterized as high-order saddle points on the potential-energy surface, and were unstable with respect to helium atom(s) loss owing to the bending motion of the -NBeHe groups. The molecules containing N, P, O, or S as the central atom also showed a variable topology and include second-order saddle points such as S(NBeHe)(2), third-order saddle points such as HN(NBeHe)(2), but also minimum-energy structures such as O(NBeHe)(2) and HP(NBeHe)(2), which are also stable by approximately 5 kcal mol(-1) with respect to the helium atom(s) loss. These results suggest the conceivable existence of an, in principle, very large class of M(NBeHe)(n) (n>1) polyhelium complexes, whose stability may be substantially affected by the nature and the size of the central moiety M. Atoms-in-Molecules (AIM) calculations on selected species invariably suggest that, in our investigated M(NBeHe)(n) (n>1) compounds, the beryllium-helium interaction is essentially electrostatic.     

Monolayers (Langmuir films) behavior of multi-component systems composed of a bile acid with different sterols and with their 1:1 mixtures

Different physicochemical properties of Langmuir films (monolayers) composed of 10 mixed systems of a bile acid, deoxycholic acid (DC) with various plant sterols, such as stigmasterol (Stig), beta-sitosterol (Sito) and campesterol (Camp) and a stanol, cholestanol (Chsta) in addition to an animal sterol, cholesterol (Ch) [these sterols and Chsta are abbreviated as St] and DC with 1:1 St mixtures; (Ch+Chsta), (Ch+Stig), (Stig+Chsta), (Ch+Sito) and (Ch+Camp) on the substrate of 5M aqueous NaCl solution (pH 1.2) at 25 degrees C, were investigated in terms of mean surface area per molecule (A(m)), the partial molecular area (PMA), surface excess Gibbs energy (DeltaG((ex))), interaction parameter (I(p)) as well as activity coefficients (f(1) and f(2)) in 2-D phase of each binary (or ternary) component system and elasticity (Cs(-1)) of formed films; these were analyzed on the basis of the respective surface pressure (pi) versus A(m) isotherms as a function of mole fraction of Sts (X(st)) in the DC/St(s) mixtures at discrete surface pressures. Notable findings are: (i) all the binary component systems did form patched film type monolayers consisting of (a) DC-dominant film solubilizing a trace amount of St molecules and (b) St dominant film dissolving a small amount of DC molecules, (ii) DC in 2-D phase exhibited a transition from LE film to LC film at a constant pressure (pi(C)(1)) accompanied by compression and (iii) DeltaG((ex)) as well as I(p) was found to be greatly dependent on (a) the combinations of DC with different St species and (b) to be markedly varied by a difference in mixing ratio of DC to Sts. Compressibility (or elasticity) analyses and fluorescence microscopy images could support the above findings as well as interpretation.     

Strontium ion-selective electrodes based on the diamides with pyridine ring as ionophores

Poly(vinyl chloride) membrane strontium ion-selective electrodes were developed by using three lipophilic diamides containing pyridine ring as ionophores. The relationship between the structure of the ionophores and the performance of these electrodes, as well as the effects of the plasticizers and additives, were investigated. The Sr(2+)-electrode based on N,N,N',N'-tetracyclohexyl-2,6-pyridine-bis(methyleneoxy acetamide) as neutral carrier, potassium tetrakis (p-chlorophenyl) borate (KTpClPB) as additive, and o-nitrophenyloctyl ether (o-NPOE) as plasticizing solvent. It exhibits excellent properties with a Nernstian slope of 29 mV/pSr(2+)and a linearity range of 2x10(-5) to 1x10(-2) M at 25 degrees C, K(Sr,Ba)(Pot)=2x10(-2).     

具酯酶活性的温敏型分子印迹微凝胶

以双醛葡聚糖-组氨酸偶连物(PAD-His)为功能大单体、过渡态类似物p-硝基苯磷酸酯(NPP)为模板分子、Co2+为中心离子,采用油包水反相乳液法首次制得具有酯酶活性的温敏型分子印迹微凝胶(MIGs).催化水解实验表明,MIGs催化活性受模板分子用量的影响,并可通过温度进行有效调控.MIGs催化p-硝基乙酸苯酯(NPA)水解反应行为可用Michaelis-Menten方程进行描述,其最大催化水解反应速率和Michaelis-Menten常数分别为2.04×10-8mol/h和2.2×10-5mol/L,且具有较好的催化选择性.     

选择性接聚乙烯醇枝聚醚氨酯的合成及其血液相容性

合成了α－甲基，ω－（２，３－环氧丙基）－聚乙二醇醚（Ⅱ）．经水解得到悬挂聚乙二醇（ＰＥＧ）枝的丙二醇－２，３（Ⅲ）．用二元醇（Ⅲ）为扩链剂制得了在硬链段上接有ＰＥＧ枝的聚醚氨酯（Ｈ－ＰＥＵ）．以四氢呋喃与少量大分子单体（Ⅱ）进行正离子开环共聚合制得每个链接有约１．３个ＰＥＧ枝的聚丁二醇（Ⅳ），用以合成了在软链段上接有ＰＥＧ枝的聚醚氨酯（Ｓ－ＰＥＵ）．ＥＳＣＡ及抗凝血性研究结果表明，不同位置接枝的ＰＥＵ，其表面都有明显的聚醚链段富集．Ｓ－ＰＥＵ抗凝血复钙时间只比未接枝者增长约２０％，而Ｈ－ＰＥＵ则增约一倍，比Ｓ－ＰＥＵ增约６０％．随ＰＥＧ最增大，复钙时间增长．     

Newly synthesized peripherally octa-substituted zinc phthalocyanines carrying halogen terminated phenoxy-phenoxy moiety: comparative photochemical and photophysical features

This study reports the 3 new phthalonitrile derivatives, namely 4, 5 Bis-[4-(4-bromophenoxy) phenoxy] phthalonitrile ( 1 ), 4,5 Bis-[4-(4-chlorophenoxy) phenoxy]phthalonitrile ( 2 ), and 4, 5 Bis[4-(4-fluorophenoxy) phenoxy] phthalonitrile ( 3 ). Their octa-substituted zinc phthalocyanines ( 4 , 5 , 6 ) are reported for the first time in this study. The resulting compounds were characterized by utilizing some spectroscopic methods, such as UV-Vis, 1HNMR, FT-IR spectroscopy, as well as mass spectraand elemental analysis. To show photosynthesizer’s potential, emission (F F ), singlet oxygen (1O2), and photodegradation quantum yields (F∆, Fd) of octa-peripherally phthalocyanines (Pcs) were performed in the solutions, such as biocompatible solvent DMSO (dimethyl sulfoxide) as well as DMF (dimethylformamide) and THF (tetrahydrofuran). Solvent and octa-peripherally binding effect of the halogen (Br, Cl, F) terminated phenoxy-phenoxy groups on phthalocyanine rings for photophysicochemical properties ( 4 , 5 , and 6 ) were compared with the tetra-peripherally and tetra nonperipherally substituted derivatives. The new dyes ( 4 to 6 ) may be evaluated in photodynamic therapy (PDT) of cancer as photosensitizers due to efficient 1O2 from 0.55 to 0.75.     

New Cu(II) compounds with ligands synthesized through nucleophilic addition of pyrazoles to dicyanamide. Synthesis,crystal structures and spectroscopy

Three newly synthesized ligands, i.e. (pyrazolecarbimido)-cyanoamine (abbreviated as Hdcapz), (3-methylpyrazolecarbimido)cyanoamine (abbreviated as Hdcampz) and (3,5-dimethylpyrazolecarbimido)cyanoamine (abbreviated as Hdcadmpz) are presented in this study, including the X-ray crystal structures for two of them, as well as their coordination behaviour with respect to Cu(II).     

Complexation of the vulcanization accelerator tetramethylthiuram disulfide and related molecules with zinc compounds including zinc oxide clusters (Zn4O4)

Zinc chemicals are used as activators in the vulcanization of organic polymers with sulfur to produce elastic rubbers. In this work, the reactions of Zn(2+), ZnMe(2), Zn(OMe)(2), Zn(OOCMe)(2), and the heterocubane cluster Zn(4)O(4) with the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and with the related radicals and anions Me(2)NCS(2)(*), Me(2)NCS(3)(*), Me(2)NCS(2)(-), and Me(2)NCS(3)(-) have been studied by quantum chemical methods at the MP2/6-31+G(2df,p)//B3LYP/6-31+G* level of theory. More than 35 zinc complexes have been structurally characterized and the energies of formation from their components calculated for the first time. The binding energy of TMTD as a bidendate ligand increases in the order ZnMe(2)相似文献   

Conformation of 2-aminomethylpyrrolidine and 2-aminomethylpiperidine in ternary platinum(II) complexes: regulation of conformation of the diamine by the coexisting ligand

Square-planar complexes with the formula [Pt(L(2))(L(1))](X)(2) x nH(2)O, where L(1) is S-2-aminomethylpyrrolidine (S-pyrda) or 2-aminomethylpiperidine (pipda) and L(2) is diammine (X=Cl), cyclobutane-1,1-dicarboxylato (cbdca) (X=none), 2,2'-bipyridine (bpy) (X=NO(3)), or 1,10-phenanthroline (phen) (X=Cl), were prepared and the nature of the coordination of L(1) was examined by (1)H-NMR spectroscopy and X-ray crystallography. These 2-aminomethylazacycloalkane derivatives form five-membered chelate rings condensed with an azacycloalkane ring in cis- or trans-configurations. The (1)H-NMR spectrum of complexes with S-pyrda as L(1) were consistent with cis-condensed rings in an S(N) conformation with any of L(2) group. However, (1)H-NMR spectra of the complexes with pipda as L(1) indicated trans-fused successive rings for the diammine and cbdca as L(2), but spectra for bpy and phen as L(2) were consistent with a conformation having cis-fused successive rings. X-Ray crystallography data for the two complexes with pipda as L(1) and cbdca (1) and bpy (2) as L(2) confirms the different coordination behavior in the solid state.     

Resistivity-Temperature Behavior of CB-Filled HDPE Foaming Composites

High-density polyethylene/carbon black foaming conductive composites were prepared from acetylene black（ACEY） and super conductive carbon black（HG-1P） as conductive filler, low-density polyethylene（LDPE） as the second component, ethylene-vinyl acetate（EVA） and ethylene propylene rubber（EPR） as the third component, azobisformamide（AC） as foamer, and dicumyl peroxide（DCP） as cross-linker. The structure and resistivity-temperature behavior of high-density polyethylene（HDPE）/CB foaming conductive composites were investigated. Influences of carbon black, LDPE, EVA, EPR, AC, and DCP on the foaming performance and resistivity-temperature behavior of HDPE/CB foaming conductive composites were also studied. The results reveal that HDPE/CB foaming conductive composite exhibits better switching characteristic; ACET-filled HDPE foaming conductive composite displays better positive temperature coefficient（PYC） effect; whereas super conductive carbon black（HG-1P）-filled HDPE foaming conductive composite shows better negative temperature coefficient（NTC） effect.     

Selective separation of magnolol using molecularly imprinted membranes

Molecularly imprinted membranes (MIMs) for selective separation of magnolol were prepared by thermal polymerization using magnolol as the template, ethylene glycol dimethacrylate (EGDMA) as the cross‐linker, 2,2‐azobisisobutyronitrile (AIBN) as the initiator, organic solvent as the porogen, methacrylamide (MAM) and acrylic acid (AA) as the functional monomers and cellulose acetate as the agglutinant. Commercial filter paper was used as the supporting material. The effects of different porogens and the ratio of functional monomers on the binding and recognition capacity of MIMs were investigated, and the morphology of the membranes was examined by scanning electron microscopy (SEM). The results showed that the MIMs have the highest selectivity to magnolol when the ratio of MAM/AA was 1:4 and tetrahydrofuran (THF) with dimethyl sulfoxide (DMSO) was used as the porogen. The morphology of the imprinted membranes after template extracting is much rougher with big cavities than that of the non‐imprinted membranes (NIMs) and the imprinted membranes before template extracting. The MIMs can selectively separate the magnolol.     

Extraction of lead(II) and copper(II) from salicylate media by tributylphosphine oxide.

Tributylphosphine oxide (TBPO) is proposed as an extractant for the extraction of lead(II) and copper(II) from salicylate media. The optimum conditions were evaluated by varying the experimental parameters, such as the pH, sodium salicylate concentration, tributylphosphine oxide (TBPO) concentration, shaking period and various diluents. The probable extracted species, deduced from log-log plots were Pb(HSal)2.2TBPO and Cu(HSal)2.2TBPO. The extraction took place through a solvation mechanism. The method permits the binary separation of lead(II) and copper(II) from commonly associated elements as well as the mutual separation of lead(II) and copper(II). The method is applicable to the determination of lead(II) and copper(II) in various alloys as well as environmental and pharmaceutical samples.     

Nanomaterialien zum Anfassen. Do‐it‐yourself !

Eight selected experiments intend at demonstrating synthesis, properties, function and application of nanomaterials. The reader should be stimulated to “Do‐it‐yourself” experiments at schools as well as at universities. In detail the experiments are: (1) Light scattering of suspensions, (2) Self‐made opals, (3) Quantum‐Size effects and red gold, (4) Surfaces and surface functionalization, (5) Pyrophoric iron, (6) Superparamagnetism and magnetic liquids, (7) TiO₂ and dye‐sensitized solar cells as well as (8) Phosphors and luminescent biomarkers. All experiments are organized to allow for simple and fast implementation, although this implies a certain limitation regarding the quality of the material properties in detail. Altogether, the interest in nanosciences and nanotechnology should be aroused as well as the curiosity to learn even more.     

Timolol maleate release from pH-sensible poly(2-hydroxyethyl methacrylate-co-methacrylic acid) hydrogels

Multifunctional polymeric materials were obtained from poly(methacrylic acid-co-2-hydroxyethyl methacrylate), to be used as a raw material in the manufacture of contact lens and as drug delivery systems. Poly(methacrylic acid-co-2-hydroxyethyl methacrylate) was prepared by free-radical polymerization in aqueous solution at 60 °C using potassium persulfate (KPS) as initiator and N,N^′-methylenebisacrylamide (BIS) as cross-linker agent. The dynamic and equilibrium swelling properties of dry glassy poly(methacrylic acid-co-2-hydroxyethyl methacrylate) polymeric networks were studied as a function of pH and methacrylic acid (MAA) content. The water content increase as MAA content and pH increase. Timolol maleate delivery from poly(MAA) and poly(2-hydroxyethyl methacrylate) (HEMA) homopolymers was studied and the results show a Fickian diffusion behavior.     

On the syntheses and some reactions of bis- and tris(methylthio)thiophenes

Reaction between various thienyllithium derivatives and dimethyl disulfide has been used for the preparation of 2,5-, 2,3-, and 3,4-bis(methylthio)thiophenes, as well as 2,3,4- and 2,3,5-tris(methylthio)thiophenes. Bromination of (methylthio)thiophenes with N-bromosuccinimide was found to be most convenient for the preparation of brominated (methylthio)thiophenes such as 3-bromo-2,5-bis(methylthio)- and 5-bromo-2,3-bis(methylthio)thiophene, 3,4-dibromo-2,5-bis(methylthio)-, 2,5-dibromo-3,4-bis(methylthio)- and 2,3-dibromo-4,5-bis(methylthio)thiophene as well as 3-bromo-2,4,5-tris(methylthio)thiophene. The reaction of methylthio substituted thienyllithium derivatives with methyl chloroformate was used for the syntheses of methyl methylthio substituted thiophenecarboxylates and using 1/3 of an equivalent for the direct preparation of methylthio substituted 3-thienylcarbinols as tris[2,4,5-tris(methylthio)-3-thienyl]carbinol.     

天然气中温SOFC阳极材料铒掺杂的氧化铈的制备与性能研究

采用溶胶-凝胶法合成了新型中温固体氧化物燃料电池(IT-SOFC)阳极材料Ce_1-xEr_xO_y(x=0.00,0.10,0.15,0.20,0.25,0.30)(EDC),并采用共压-共烧结法制备了以NiO-EDC复合阳极为支撑、以Ce_0.8Gd_0.2O_2-δ(GDC)为电解质、以La_0.8Sr_0.2Co_0.8Fe_0.2O_3-δ(LSCF)-GDC为复合阴极的单电池。利用XRD和SEM等方法对阳极材料EDC进行了晶相结构、微观形貌和化学相容性等分析。在400~700 ℃范围内,以加湿天然气(3% H₂O)为燃料气,氧气为氧化气测试了电池的电化学性能。结果表明：EDC阳极材料具有良好的孔道结构;11种不同阳极组成的单电池中50%(质量分数)NiO-50%(质量分数)Ce_0.85Er_0.15O_y(E15C85)阳极支撑的单电池具有最佳的电化学性能,在650 ℃时其最大电流密度为117.84 mA·cm^-2和最大比功率为24.37 mW·cm^-2。     

Preparation of ethambutol-copper(II) complex and fabrication of PVC based membrane potentiometric sensor for copper

Copper(II) complex of ethambutol (I) was prepared and used in the fabrication of Cu(2+) selective ISE membrane. The membrane having Cu(II)-ethambutol complex (I) as electroactive material, along with sodium tetraphenylborate (NaTPB) as anion discriminator, dioctylphthalate (DOP) as plasticizer in poly(vinyl chloride) (PVC) matrix in the percentage ratio 6:2:190:200 (I:NaTPB:DOP:PVC) (w/w) gave a linear response in the concentration range 7.94x10(-6) to 1.0x10(-1) M of Cu(2+) with a slope of 29.9+/-0.2 mV per decade of activity and a fast response time of 11+/-2 s. The sensor works well in the pH range 2.1-6.3 and could be satisfactorily used in presence of 40% (v/v) methanol, ethanol and acetone and is selective for copper over a large number of cations with slight interference from Na(+) and Co(2+) if present at a level 1.5x10(-5) and 6.5x10(-5) M, respectively. It works well over a period of 6 months and can also be used as indicator electrode for the end point determination in the potentiometric titration of Cu(2+) against EDTA as well as in the determination of Cu(2+) in real samples.     

An Electrochemical Biosensor Platform for Testing of Dehydroepiandrosterone 3‐Sulfate (DHEA−S) as a Model for Doping Materials

Endogenous steroids such as dehydroepiandrosterone (DHEA) and dehydroepiandrosterone 3‐sulfate (DHEA?S) have commonly used as doping materials by athletes and to date novel techniques are needed for detection of these molecules. In this study, antibody‐based electrochemical biosensor has developed for testing level of the DHEA?S. For this aim, gold surfaces were initially modified with cysteamine (Cys) and then, DHEA?S antibody was immobilized on the surface via glutaraldehyde (GA) as a crosslinking agent. The stepwise modification of electrode surface was monitored by using various electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Linear range was determined as 2.5–100 ng/mL DHEA?S using differential pulse voltammetry (DPV) technique, as well. Moreover, repeatability (±S.D.), coefficient of variation (%) and limit of detection (LOD) values were calculated as 0.033, 1.030 and 3.971, respectively. Also, DHEA?S in synthetic serum and urine samples were successfully determined with standard addition method and confirmation analysis were performed with liquid chromatography quadrupole‐time of flight mass spectrometry (LC‐QTOF/MS) system. The selectivity was studied with the addition of some interfering molecules (testosterone, bovine serum albumin (BSA), cholesterol, uric acid, lactic acid, codein (COD), ascorbic acid, DHEA). Consequently, this work is proposed as practical, innovative and cost‐effective technique that can be easily adapted for the miniaturized form for the analysis of other doping substances as well as DHEA?S for the future works.