Spectroscopic characterization and stereodynamics of ferrocenylselenoethers Pt(II), Pd(II), Rh(III) complexes

Ferrocenlyselenides (C₅H₅FeC₅H₄SeR, Fe(C₅H₄SeR)₂) and their complexes of metal Pt, Pd, Rh (R=undecenyl, benzyl, phenyl) have been prepared. The spectroscopic characterization has been examined by mass spectrum, XPS, IR and NMR. IR, NMR spectra of C₅H₅Fe C₅H₄Se (CH₂)₉ CH=CH₂PtCl₂ reveal C=C double-bond in Fe(C₅H₄Se (CH₂)₉CH=CH₂)₂ Pt Cl₂ is free because of binding with Pt(II). The results obtained from^H,¹³C and⁷⁷Se NMR indicate that invertomers ofmeso anddl species existence. The ratio ofmeso/dl for BUnSeF Pt is ca 70/30, whereas four and three invertomers for BUnSeF Pt and BBSeFPd have been clearly observed from¹H NMR spectra. Tian Bingshou: born in Feb. 1938, Associate professor     

Enolate chelating N-heterocyclic carbene complexes of Fe(II): Synthesis, structure and their catalytic activity for ring-opening polymerization of ε-caprolactone

The reaction of anhydrous FeBr2 with two equivalents of anionic N-heterocyclic carbene (NaL1 and NaL2), which are generated in situ by the reaction of the corresponding salt [4-R-C6H4COCH2{CH- (NCHCHNiPr)}Br] (R = OCH3, H2L1Br, 1; R = F, H2L2Br, 2) with two equivalents of NaN(SiMe3)2, affords bis-ligand Fe(II) complexes of L12Fe (3) and L22Fe (4) in high yield, respectively. Attempt to synthesize mono-ligand Fe(II) bromide by the 1:1 molar ratio of NaL to FeBr2 is unsuccessful, and the same com- plexes of 3 and 4 were obtained. Both 3 and 4 have been depicted by elemental analysis and X-ray structure determination. Preliminary studies show that both 3 and 4 can be used as single-component catalyst for the ring-opening polymerization of ε-caprolactone, and the catalytic activity of 3 is higher than that of 4.     

Electrochemical behavior of novel bis (aliphatic amine) ruthenium (II) and osmium (II) porphyrins

Bis (aliphatic amine) ruthenium (II) and osmium (II) porphyrins, M (Por)-(H₂NR)₂ and M(Por)(HNR′₂)₂, [M=Ru and Os; Por=meso-tetrakis (p-tolyl) porphyrinato (TTP), meso-tetrakis (4-chlorophenyl) porphyrinato (4-Cl-TPP), meso-tetrakis (3, 5-dichlorophenyl) porphyrinato (3, 5-Cl-TPP) and meso—tetraphenyl porphyrinato(TPP); R=methyl, ethyl, iso-propyl and t-butyl; R′=methyl and ethyl] were synthesized by us. The electrochemical behavior of these complexes in 1, 2-dichloroethane with TBABF₄ as supporting electrolyte, has been studied by cyclic voltammetry and controlled potential electrolysis. Bis (aliphatic amine) ruthenium (II) porphyrins under go reversible one-electron oxidation and one-electron reduction processes in 1,2-dichloroethane solution. The osmium (II) analogues is shown two oxidation couples III and V, an additional small wave IV. The redox potentials of these complexes are markedly dependent on the nature of the substituent bound to the phenyl group of the porphyrin ring. It is obvious that redox potentials increases the electron-withdrawing power of the substituents increases. The couple I was found at −0.34, −0.23 and −0.15 V vs Cp₂ Fe^+/0 (Cp₂Fe=ferrocene) for Ru(TPP)(H₂NBu-t)₂, Ru(4-Cl-TPP) (H₂NBu-t)₂ and Ru(3,5-Cl-TPP)(H₂NBu-t)₂ respectively. Supported by the foundation of the Chinese Education Commission Li Zaoying: born in 1949, Associate Professor     

Electrochemical behavior of novel bis (aliphatic amine) ruthenium (II) and osmium (II) porphyrins

Bis (aliphatic amine) ruthenium (II) and osmium (II) porphyrins, M (Por)-(H₂NR)₂ and M(Por)(HNR′₂)₂, [M=Ru and Os; Por=meso-tetrakis (p-tolyl) porphyrinato (TTP), meso-tetrakis (4-chlorophenyl) porphyrinato (4-Cl-TPP), meso-tetrakis (3, 5-dichlorophenyl) porphyrinato (3, 5-Cl-TPP) and meso—tetraphenyl porphyrinato(TPP); R=methyl, ethyl, iso-propyl and t-butyl; R′=methyl and ethyl] were synthesized by us. The electrochemical behavior of these complexes in 1, 2-dichloroethane with TBABF₄ as supporting electrolyte, has been studied by cyclic voltammetry and controlled potential electrolysis. Bis (aliphatic amine) ruthenium (II) porphyrins under go reversible one-electron oxidation and one-electron reduction processes in 1,2-dichloroethane solution. The osmium (II) analogues is shown two oxidation couples III and V, an additional small wave IV. The redox potentials of these complexes are markedly dependent on the nature of the substituent bound to the phenyl group of the porphyrin ring. It is obvious that redox potentials increases the electron-withdrawing power of the substituents increases. The couple I was found at −0.34, −0.23 and −0.15 V vs Cp₂ Fe^+/0 (Cp₂Fe=ferrocene) for Ru(TPP)(H₂NBu-t)₂, Ru(4-Cl-TPP) (H₂NBu-t)₂ and Ru(3,5-Cl-TPP)(H₂NBu-t)₂ respectively. Supported by the foundation of the Chinese Education Commission Li Zaoying: born in 1949, Associate Professor     

Crystal structure and surface photo-electric property of Mn（Ⅱ） coordination supramolecules

Two Mn（Ⅱ） coordination supramolecules, [Mn2（C8HTO2）4（phen）2（p-H20）] （1） and [Mn2（btec）（phen）2（H2O）6]·2H2O （2） （phen=1,10-phenanthroline, H4btec=1,2,4,5-benzenetetracarboxylic acid）, were synthesized by hydrothermal method. The crystal structures of the complexes were determined by X-ray single crystal diffraction. The result indicates that （1） and （2） are both binuclear Mn（Ⅱ） complexes. The existence of hydrogen bonds makes the binuclear complexes become further connected to coordination supramolecules, which possess 1D and 3D infinite structures respectively. The complexes were identified by IR, UV-Vis, surface photovoltage spectrum （SPS） and field-induced surface photovoltage spectrum （FISPS）. The results of SPS for the complexes indicate that they both exhibit positive surface photovoltage response bands in the range of 300-600 nm. The SPS phase spectrum and FISPS of complexes indicate that they show certain p-type semiconductor characteristic. However, the intensity, position and number of the SPV response bands are different obviously. The difference of the SPV response bands is mainly attributed to the different structures of the complexes and the different coordination environment of Mn（ll） in the two complexes. This paper discusses the action of hydrogen bonds in the construction of the supramolecule and the change on the surface photovoltage of complex in different coordination environment.     

Equilibrium dialysis study on the interaction between Cu(II) and HSA or BSA

The interaction of Cu(II) and human serum albumin (HSA) or bovine serum albumin (BSA) at physiological pH is studied by equilibrium dialysis. The successive stability constants are obtained by non-linear least square methods fitting Bjerrum formula. For both the Cu(II)-HSA and Cu(II)-BSA systems, the order of magnitude of K₁ and K₂ was found to be ≈10⁴ mol⁻¹· dm³. There are about twenty stoichiometry binding sites found in one HSA or BSA molecule. They can be divided into two or three sets. Results of equilibrium dialysis experiments suggest that there exists one strong metal binding site in both Cu(II)-HSA and Cu (II)-BSA. It is the imidazol group nitrogen atoms of His³ that are primarily concerned with copper binding site. After reaching dialysis equilibrium, there is the interaction among the different binding sites, the values ofK all deviate from the simple statistical effect except forK ₁ and K₂ in both Cu(II)-HSA and Cu(II)-BSA systems, and the positive cooperative effect is found.     

The strong cooperativity of dioxygen binding by dicobalt (II) diporphyrin compounds in nonaqueous solution at room temperature

Thermodynamic data were determined for the reversible binding of O₂ to two compounds of dicobalt(II) di(meso-tetra-phenyl)porphyrin derivatives with different lengths of diamidoaliphatic bridge (abbreviated to Co₂PP₈ and Co₂PP₄) in N,N-dimethylformamide at room temperature. The partial pressure of dioxygen necessary for half-oxygenation (P _1/2) and hill coefficient (n) at 298 K were determined as follows:P _1/2=54.2 kPa,n=2.0 for Co₂PP₈ andP _1/2=6.8 kPa,n=1.8 for Co₂PP₄, respectively. The rate equations of reversible oxygen binding by Co₂PP₈ were determined and the reaction path was proposed. The results of ther-modynamic and kinetic studies indicate that there exists strong cooperative effect during oxygenation of the compounds. The ESR observation reveals that the dioxygen complexes formed in the solutions are of superoxo (Co-O ₂ ⁻ ) type. Supported by the Research Foundation of the State Education Commission of China Zhou Xiaohai: born in 1962, Ph.D. Associate professor     

凹凸棒土负载硫化纳米零价铁对水中Cu(Ⅱ)的去除机理研究

针对纳米零价铁易团聚及表面形成钝化层的缺点,本文以凹凸棒土为载体、以硫代硫酸钠为硫化试剂,制备了凹凸棒土负载硫化纳米零价铁(S-nZVI@ATP)复合材料,并考察了复合材料对水中Cu(Ⅱ)的去除效果。由SEM可观察到,经过凹凸棒土负载及硫化改性后的纳米零价铁串珠状结构变短,且被分散为单个的球形颗粒;比表面积测定结果表明,S-nZVI@ATP复合材料的BET比表面积为46.04m~2/g,与纳米零价铁相比提高了约1.35倍;由TEM观察到,经硫化的纳米零价铁颗粒界面处包裹了一层FeS,粒径由57.6nm增至118.5nm。S-nZVI@ATP复合材料去除水中Cu(Ⅱ)的机理主要是硫化纳米铁界面处的Fe~0将Cu~(2+)还原为Cu~0以及FeS转化为溶度积更小的CuS,该过程符合Langmuir-Hinshelwood吸附/还原模型和Langmuir等温吸附模型。本实验条件下,复合材料对Cu(Ⅱ)的最大吸附-还原量可达9.25mmol/g(587.8mg/g)。     

Synthesis,Structural Characterization,and Electrochemical Properties of Binuclear Copper(Ⅱ) Complexes Containing Tetradentate Schiff Base Ligand

Two binuclear copper(Ⅱ) complexes, [Cu2(saloph)2 (μ-O)2]-2(DMF)[H2saloph=N,N′-o-phenylenebis(salicylideneaminato)] (a) and [Cu2(salen)2(μ-O)2] [H2salen=N,N′-bis(salicylic-deneaminato) ethylene] (b)were synthesized and characterized by X-ray crystallography. Both of them have distorted rectangular pyramidal geometry around Cu(Ⅱ). The complete series of complexes show bridging phenoxo groups between the copper centers, together with hydroxo-bridges in these complexes. The complexes have also been characterized by elemental analysis, IR, TG-DTA, and electrochemical results.     

HPLC determination of ascorbic acid using luminol-Cu (II) chemiluminescence-application to the analysis of Juice beverage

The chemiluminescence (CL) of luminol-Cu (II) was applied to HPLC determination of ascorbic acid, which was separated by a C₁₈ reverse-phase column with a mobile phase of 0.25 mol/L HAc. The eluted ascorbic acid was mixed with 0.3 mmol/L luminol and 0.05 mol/L CuSO₄. The light emission from the reaction of Cu(II) oxidized ascorbic acid and luminol was detected by a modified luminometer. The detection limit was 3.6×10⁻⁶ mol/L for ascorbic acid at aS/N ratio of 3, and the linear calibration range was 2×10⁻⁴–2×10⁻³ mol/L. The relative standard deviation for 5 replicate injections of 1×10⁻³ mol/L ascorbic acid was calculated as 4.3%. The method was successfully applied to determination of ascorbic acid in juice beverage. Foundation item: National Natural Science Foundation of China (29605001) Biography: Wu Feng-wu(1963-), male, research direction: analytical chemistry.     

Adrenomedullin inhibits the endothelin production induced by urotensin II in rat vascular smooth muscle cells

The aim of this study was to observe the effects of adrenomedullin (ADM) on endothelin (ET) production induced by urotensin Ⅱ (UⅡ) in rat vascular smooth muscle cells (VSMCs). Cultured VSMCs which were incubated with UⅡ (10^-8 mol/L) and with various concentrations of ADM were used to measure the VSMCs ³H-TdR incorpora- tion, the activity of extracellular signal-regulated kinase (ERK), the amount of ET mRNA and ET production in VSMCs. In this work we found that incubation with UⅡ(10^-8 mol/L) increased obviously the amount of ET mRNA in VSMCs and ET production in medium, however, coincubation with ADM (10^-10—10^-8 mol/L) and UⅡ(10^-8 mol/L) reduced the amount of ET mRNA by 15%, 24% and 45% (P< 0.01) respectively, compared with UⅡ alone. The content of ET in medium was 14.13, 11.38 and 11.00 pg/mL. ADM alone (10^-8 mol/L) had no effect on ET production in VSMCs. UⅡ (10^-8 mol/L) promoted the 3H-TdR incorpo- ration and activity of ERK in VSMCs. ADM inhibited VSMCs 3H-TdR incorporation and activation of ERK in a concentration-dependent manner. Compared with UⅡ group, after coincubation with ADM (10^-10—10^-8 mol/L) and UⅡ (10^-8 mol/L) the VSMCs 3H-TdR incorporation was decreased by 7% (P > 0.05), 32% (P < 0.05) and 41% (P < 0.01), respectively, and the activity of ERK was decreased by 24% (P > 0.05), 32% (P < 0.05) and 36% (P < 0.05), re- spectively, in a concentration-dependent manner. The results show that in cultured VSMCs ADM inhibits ET mRNA expression, ET production and proliferation stimulated by UⅡ, and that inhibitory effect of ADM on UⅡ bioaction could be mediated through inhibiting MAPK pathway.     

N-(3-苯甲酰丙烯酰基)水杨酰肼的合成和抗炎活性

为探讨双酰肼类化合物的合成方法和抗炎活性,以水杨酸甲酯和水合肼合成了水杨酰肼,通过傅克酰基化反应合成了3-苯甲酰丙烯酸,再与二氯亚砜反应获得了相应的3-苯甲酰丙烯酰氯,最后用水杨酰肼与3-苯甲酰丙烯酰氯反应得到N-(3-苯甲酰丙烯酰基)水杨酰肼.并对化合物进行了元素分析、IR、1H NMR和13C NMR表征,应用爪掌肿胀法进行了生物体抗炎活性测试.结果表明:N-(3-苯甲酰丙烯酰基)水杨酰肼具有较好的抗炎活性,值得进一步研究探讨.     

Synthesis and characterization of amphiphilc block copolymer poly(methyl acrylic acid)-block-polytetrahydrofuran

Under the specially designated condition the polymerization of both tetrahydrofuran (THF) andtert-butyl methacrylate (tBMA) is a living one. The diblock copolymer, poly(tert-butyl methacrylate)-block-polytetrahydrofuran (PtBMA-b-PTHF), was successfully synthesized by means of the coupling reaction of living cationic PTHF⁺, SbF₆ with living anionic PtBMA^-, Li⁺. LiCI, which has a beneficial effect on the molecular weight distribution (MWD) in the anionic polymerization of (meth)acrylates, hinders the coupling reaction of living chains and cannot be used in the preparation of tBMA precursor. The hydrolysis of the aforementioned diblock copolymer under acid condition results in the amphiphilic diblock copolymer, i.e. poly(methy1 acrylic acid)-block-polytetrahydrofuran (PMAA-b-PTHF). The diblock copolymers were characterized with GPC and IR.     

Solid-phase preparation and characterization of Chitosan

0　IntroductionChitosanhasbeenwidelyusedinpharmaceu tical,agriculturalandindustrialfieldbe causeofitsintriguing properties[1 ] .Chemicalmethodstopreparechitosanfromchitinhavebeenbroadlystudiedincludingsolutionmethod ,meltedalkalinemethod,microwavesemi drymethod ,improvedLinelbergmethod ,dissolution precipita tionmethodandsoon ,inwhichalkalinewasallusedasthecatalyst[2 ] .Biologicalmethodwasapromisingwayinthatitproducedlittleenviron mentalpollutionanditsreactionconditionsweremild .However,thism…     

PEG-g-poly（aspartamide-co-N,N-dimethylethylenediamino aspartamide）： Synthesis, characterization and its application as a drug delivery system

PEG-g-poly(aspartamide-co-N,N-dimethylethylenediamino aspartamide) (PEG-DMEDA-PASP) was synthesized by two-step ring-opening reactions of polysuccinimide (PSI) with α-methoxy-ω-amino-poly(ethylene glycol) and N,N-dimethylethylenediamine. The polymer structure was confirmed by ¹H NMR and FT-IR. The resultant PEG-DMEDA-PASP with ammonium glycyrrhizinate (AMG) could form polymeric micelles in aqueous solution. The results of transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements revealed that these polymeric micelles were spherical particles with a narrow diameter distribution and that their average diameter was ca. 70 nm. These polymeric micelles had high-loading capacity (58%) and encapsulation efficiency (70%) for AMG. The results of in vitro release experiments showed that these polymeric micelles possessed sustained-release effects, with a release rate of 25% within 3 h and 90% within 24 h.     

Crystal structure and photoelectricity property of Fe(II/III) coordination supermolecules

Three new mixed-ligand Fe(II/III) complexes [Fe₂(μ₂–btec)(μ₂–H2btec)(phen)₂(H₂O)₂]_n (1), [Fe2(btec) (phen)₂(H₂O)₄] (2), and {[Fe(o-pha)(phen)(H₂O)]•H₂O}_n (3) (phen=1,10-phenanthroline, o-H₂pha=o-phthalic acid, H₄btec=1,2,4,5-benzenetetracarboxylic acid) have been hydrothermally synthesized and detected by single crystal X-ray diffraction, showing that complexes (1) and (2) are both bridged by the betc⁴⁻ ligands to form 1D chain and dinuclear structure and complex (3) is bridged by the o-pha groups to form 1D chain structure. The coordinated modes of the carboxyl groups adopt μ₂-η¹η¹ηη¹η¹ and μ₂-η²η¹ respectively in com-plexes (2) and (3). The betc groups in complex (1) show two different coordinated modes: μ₂-η¹η¹η¹η¹ and μ₂-η¹η¹. In addition, the hydrogen bonds and π…π type interactions make the complex molecule further connect to three-dimensional and two-dimensional networks respectively. These complexes are detected by IR, UV-Vis-NIR and surface photovoltage spectrum (SPS). The SPS of complexes (1)–(3) indicate that there are positive SPV responses in the range of 300–600 nm and show p-type semiconductor characteristic. Because the structure, the valence and the coordinative environment of the Fe ions are all different in the three complexes, the intensity, position and the number of the response bands are different obviously. The results of SPS are corresponding with UV-Vis-NIR spectra.     

NMR studies of the interaction betweenBacillis subtilis neutral proteinase and inorganic metal compounds

The interaction betweenBacillis subtilis neutral proteinase (B.S.NP) and inorganic metal compounds (CoCl₂, NiCl₂) was investigated by¹H NMR spectroscopy. It has been shown that the Zn(II) ion in the active center of the native enzyme may directly interact with external CoCl₂ and NiCl₂, producing Co(II)- and Ni(II)-substituted derivatives, and their¹H NMR spectra were obtained for the first time. From the¹H NMR spectra, the coordinated structure of the active center in the native enzyme was described.     

Photoelectrical performance of nanocrystalline TiO2 film electrode sensitized by Ru(II)-bipyridine complexes

Two kinds of Ru(II)-bipyridine complexes,cis-di(thiocyanate)bis(2,2′-bipyridyl-4,4′-dicarboxylate) ruthenium(II) andcis-di(thiocyanate)bis(2, 2′-bipyridyl-3, 3′-dicarboxylate) ruthenium(II), were utilized as the sensitizers to the nanocrystalline TiO₂ film electrodes. Study shows that the two dyes have quite different sensitization properties due to the strong steric effect of carboxyl groups. In addition, the pretreatment to nanocrystalline TiO₂ film electrodes with TiCl₄ was investigated, which is an effective way to improve the photoelectric conversion performances of sensitized TiO₂ electrodes.     

Label-free selective sensing of Pb2+ lead(II) sensors based on the aggregation of a pyrene fluorescent probe

In the present work, we report a label-free fluorescence turn-on approach for the sensitive and selective sensing of Pb²⁺. Pyrene with one positive charge was used as the fluorescent probe, and thrombin aptamer (TBA), which was a G-rich oligonucleotide, was employed to form G-quadruplex with lead(II). When TBA and Pb²⁺ were mixed with lead(II) in an aqueous solution, it was folded into a stable G-quadruplex. Subsequently, a single-stranded nucleic acid-specific nuclease S1 was added. The G-quadruplex stabilized by Pb²⁺ lead(II) had markedly a significant resistant ability to nuclease S1 digestion. However, in the absence of Pb²⁺ lead(II), no quadruplex or less stable quadruplex was formed and TBA was digested by nuclease S1 in 3 min under the optimized experimental conditions. Finally, pyrene probe was mixed with oligonucleotide in Pb²⁺ lead(II). Electrostatic interactions between oligonucleotide (a polyanion) and the probe induced the aggregation of the probe, which in turn produced strong emission of the strong pyrene excimer emission. The intensity of the induced excimer emission was directly proportional to the amount of Pb²⁺ added. Our approach shows good selectivity and sensitivity for the detection of Pb²⁺ with a limit of detection limit as low as 800 nmol/L.     

Kinetic studies of the decomposition reaction of adducts of dinuclear Fe(Ⅱ)/O2

Kinetic studies of the decomposition reaction of dinuclear Fe(Ⅱ) adducts [Fe₂(N-Et-HPTB){O₂P(OPh)₂}](Cl- O₄)₂ (1) and [Fe₂(N-Et-HPTB) {O₂P(Ph)₂}] (ClO₄)₂ (2) with O₂ have been carried out at low temperature using UV-vis spectra. The decomposition reaction of Fe(Ⅱ)/O₂ adducts was first-order in the experimental conditions, and the activation parameters were obtained. ?H^¹ = 85.62 kJ·mol^-1, ?S¹ = 19.43 J·mol^-1·K^-1 for compound (1) and ?H^¹ = 97.97 kJ·mol^-1, ?S^¹ = 55.68 J·mol^-1·K^-1 for compound (2). These results are similar to those of dioxygen adducts of other metals complexes and natural enzymes such as methane mono- oxygenase (MMOH).