A Novel Uranyl Complex with Dimeric Lacunary Polyoxoanion: [(A-α-SiW<Subscript>9</Subscript>O<Subscript>33</Subscript>)<Subscript>2</Subscript>K{UO<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)}<Subscript>2</Subscript>]<Superscript>11−</Superscript>

A novel uranyl complex with dimeric lacunary polyoxoanion like open-mouthed clam, Na₅[(A-α-SiW₉O₃₃H₃)₂K{UO₂(H₂O)}₂], was prepared and characterized by elemental analysis, infrared and ultraviolet–visible spectroscopy and single crystal X-ray diffraction. In the anion, two A-α-SiW₉O₃₄¹⁰⁻ groups share two terminal oxygen atoms O_d′ derived from removal of three corner-shared W atoms from saturated α-Keggin anion, forming a dimeric anion with an open mouth in which potassium ion and uranyl ions are coordinated. Uranium atom adopts a pentagonal bipyramidal geometry. The coordinating anions are linked by sodium ions via coordination of terminal or bridging oxygen atoms, forming two-dimensional layer arrangement. Between the layers are the hydrogen bonds from which a supramolecular architecture is created. UV–VIS spectrum gives W–O and U–O charge transfer transitions at 230–265 and 432 nm, showing the change of geometry of the polyanion and weakening of the U–O bonds of the uranyl cation. Electronic supplementary material The online version of this article () contains supplementary material, which is available to authorized users.     

A novel Ce<Superscript>III</Superscript>-cyclam type complex and its redox chemistry in aqueous solutions

A new Ce^III complex was synthesized by mixing the ligand “dioxocyclam” with Ce^III ions at pH 8.0 and its redox properties were investigated.

A Novel Dimeric BINOL for Enantioselective Recognition of 1,2‐Amino Alcohols

A novel auxillary chiral dimeric binol has been designed, synthesized, and used to enantioselectively recognize 1,2‐amino alcohols through the three point of interactions, the reversible imine bond, resonance assisted hydrogen bonding and the hydrogen bonding by the additional chiral moiety introduced at the receptor. The enantioselectivities were comparable to those of the previous reported receptors.     

A Novel 3D Supramolecular Network Constructed from [Cu(4,4'-bipyridine)(O_2CMe)_2]_2 Molecular Ladders by Hydrogen Bonding

1 INTRODUCTION In recent years, the assembly of extended supra- molecular architectures from molecular building units has yielded a new generation of materials with diverse network topologies[1～3]. A number of such frameworks have been found to exhibit fascinating physical and chemical properties. The investigation of hydrogen bonding is important for many practical applications, such as the design of antibiotics and development of new materials with programmed properties[4]. A great va…     

Effect of Ce<Superscript>3+</Superscript> on spectral characteristic of D1/D2/Cytb559 complex from spinach

It was studied by spectroscopy that PSII reaction center complex consisting of three polypeptides, D₁, D₂ and Cytb559, were purified from PSII particle of CeCl₃ treated spinach. The results of the experiment show that Ce³⁺ could improve the growth of spinach, and accelerate electron transport of PSII particles. Of chl-a of UV-Vis spectrum of D1/D2/Cytb559 complex, Soret band was blue-shifted by 3 nm and Q band by 2 nm, respectively, and the fluorescence emission peak was blue-shifted by 5 nm in CeCl₃-treated spinach compared with the one in control. By the extended X-ray absorption fine structure (EXAFS) spectroscopy methods, it has been found that Ce³⁺ is coordinated with 8 nitrogen atoms in the first coordination shell with Ce-N bond length of 0.253 nm, and Ce³⁺ with 6 oxygen atoms in the second coordination shell with Ce-O bond length of 0.32 nm. However, the secondary structure of D1/D2/Cytb559 complex by circular dichroism (CD) spectroscopy has no significant change after CeCl₃ treated. It might be that Ce³⁺ binds to porphyrin rings of chlorophyll and oxygen of amino acid residue of polypeptide in D1/D2/Cytb559 complex, and then accelerates the primary reaction of PSII, intensifies function of P680⁺ primary electron donor of D1/D2/Cytb559, but there is little change in conformation of PSII reaction center complex.     

Effects of La<Superscript>3+</Superscript> on inward K<Superscript>+</Superscript> channels at plasma membrane in guard cells

The effects of La³⁺ on inward K⁺ channels at plasma membrane in vicia guard cells are investigated using the whole-cell patch-clamp recording mode. It is shown that La³⁺ on both sides of plasma membrane blocks inward K⁺ currents in a concentration-dependent manner, indicating that La³⁺ binding sites may exist on both sides of plasma membrane in guard cells in vicia. The dose response is fitted by the Michaelis-Menten relation characterized by an inhibitor constant K _i of 2.56±0.25 μmol · L⁻¹ (outside membrane) and (1.18±0.11)×10⁻¹⁵ mol · L⁻¹ (inside membrane). Intracellular La³⁺ has much stronger inhibitory effect on inward K⁺ currents than extracellular La³⁺ does, suggesting there may exist stronger binding sites inside membrane than outside membrane. Since ion channel activities of guard cells directly affect plant stomatal movement and water status, our results imply that rare earth elements might have potential practical values in regulating plant water status and strengthening plant drought endurance.     

Theoretical study on the reaction mechanism of (CH<Subscript>3</Subscript>)<Subscript>3</Subscript>CO<Superscript>.</Superscript> radical with NO

The reaction mechanism of (CH₃)₃CO^. radical with NO is theoretically investigated at the B3LYP/6-31G* level. The results show that the reaction is multi-channel in the single state and triplet state. The potential energy surfaces of reaction paths in the single state are lower than that in the triple state. The balance reaction: (CH₃)₃CONO⇔(CH₃)₃CO^.+NO, whose potential energy surface is the lowest in all the reaction paths, makes the probability of measuring (CH₃)₃CO^. radical increase. So NO may be considered as a stabilizing reagent for the (CH₃)₃CO^. radical.     

NMR Spectra of Cyclic Nitrones. 7. The Influence of Substituents and a Hydrogen Bond on <Superscript>14</Superscript>N and <Superscript>17</Superscript>O Chemical Shifts in Derivatives of 3-Imidoazoline 3-Oxide

Derivatives of 3-imidazoline 3-oxide have been studied by ¹⁴N and ¹⁷O NMR methods. Regularities of the influence of substituents and of a hydrogen bond on chemical shifts have been made apparent. The range of changes of the chemical shifts of the nitrogen and oxygen nuclei of the nitrone group has been determined. Both in the ¹⁷O and in the ¹⁴N NMR spectra the signals of the amino derivatives are the highest field signals for the nitrone group, and the lowest field signals are the signals of the cyano derivatives in the series of derivatives investigated. Depending on the substituent (from amino to cyano group) the ¹⁷O chemical shifts varied over a range ∼155 ppm, but the interval of change of the ¹⁴N chemical shifts for the same substituents was ∼110 ppm. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1336–1341. September, 2005.     

A combined experimental and theoretical study on the complexation of Li<Superscript>+</Superscript> with valinomycin

Abstract  From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant of the valinomycin–lithium complex in nitrobenzene saturated with water was determined. Further, the structure of the resulting complex was indicated by means of the density functional level of theory (DFT) calculations. Graphical abstract        

A Novel Three—dimensional Framework with Tunnels Based on the Cobalt—containing Molybdenum Phosphate Moieties

IntroductionThedesignandsynthesisoforganic inorganichybridma terialsareofgreatinterestinmaterialscienceowingtotheirextensiveapplicationsincatalysis ,sorptionandelectricalconductivity.1 4 Exploitationofhydrothermaltechniquesanduseoforganicstructure directingagentshavebeenprovedfruitfulmethodsintheproductionoforganic inorganichybridmaterials.5,6 Metaloxideclustersbasedonanionicmolybde numphosphatesareoneofexcellentsubfieldswithabundantstructures.Itiswellknownthatmolybdenumphosphatesathydrotherma…     

A Prototype of a Volumetric Three‐Dimensional Display Based on Programmable Photo‐Activated Phosphorescence

A proof‐of‐principle prototype of a volumetric 3D‐displaying system is demonstrated by utilizing the photo‐activated phosphorescence of two long‐lived phosphorescent metal‐porphyrins in dimethyl sulfoxide (DMSO), a photochemically deoxygenating solvent. The first phosphorescent sensitizer, Pt(TPBP), absorbs a light beam with a wavelength of 635 nm, and the sensitized singlet oxygen is scavenged by DMSO. The second phosphorescent emitter, Pt(OEP), absorbs a light beam with a wavelength of 532 nm and visibly phosphoresces only in the deoxygenated zone generated by the first sensitizer. The phosphorescent voxels, 3D images, and animations are well‐defined by the intersections of the 635‐nm and 532‐nm light beams that are programmable by tuning of the excitation‐power densities, the beam shapes, and the kinetics. As a pivotal selection rule for the phosphorescent molecular couple used in this 3D‐displaying system, their absorptions and emissions must be orthogonal to each other, so that they can be excited and addressed independently.     

基于三维纳米银修饰电极的硝酸根微型传感芯片研究

研制一种基于金叉指微电极阵列(IDA)的电流型硝酸根离子(NO-3)微传感电极芯片.基于微机电系统(Micro-Electro-Mechanical Systems,MEMS)工艺制备金IDA微电极,通过电化学沉积技术在IDA微电极表面修饰三维枝状结构纳米银敏感膜,利用敏感膜对硝酸根离子良好的电催化还原性能,采用脉冲方波伏安(SWV)电化学测量方法,实现对硝酸根离子在25～1000μmol/L浓度范围内的快速检测,灵敏度达9.5 nA/(μmol/L),线性度为99.98%,检测下限为10μmol/L.考察水体中常见的NO-2,F-,3PO 4-,SO 42-,2CO3-,NH+4,Na+和K+等离子对该传感芯片的干扰性能,传感芯片表现出较好的抗干扰性能.制备的三维枝状结构纳米银修饰IDA微电极可实现水环境(pH 5.0～9.0)中NO-3的电化学检测,对应用于自然水环境中硝酸根离子的现场检测具有积极意义.     

基于昆虫气味结合蛋白的新型酰基哌啶类化合物的构效关系

利用Sybyl7.3软件对29个具有驱避活性的新型酰基哌啶类化合物与气味结合蛋白AgamOBP1的结合模式进行研究,发现二者之间的结合以疏水作用和水桥作用为主. 其中酰基哌啶类化合物末端的疏水片段可与AgamOBP1结合腔内狭长的疏水通道产生相互作用. 同时,其关键药效基团——酰基氧可通过HOH153与AgamOBP1中的关键残基Trp114和Gly92或Cys95形成多重氢键作用. 利用比较分子力场分析法（CoMFA）和比较分子相似性指数分析法（CoMSIA）构建了新型酰基哌啶类化合物的三维定量构效关系（3D-QSAR）模型,其交叉验证系数r_cv²分别为0.650和0.587. 研究表明,在CoMSIA模型中,疏水场、静电场和立体场组合所得的三维构效关系模型最佳,其中尤以疏水场对这类酰基哌啶类化合物的驱避活性最为重要. 基于AgamOBP1靶标结合口袋特征和酰基哌啶类化合物的3D-QSAR模型得出具有驱避活性的酰基哌啶类化合物的构效关系如下：在酰基C上引入一定碳链长度的疏水基团可使化合物表现出驱避活性,其中又以含9~10个C的化合物的驱避活性最佳,这与AgamOBP1结合口袋的疏水性质密不可分;当酰基端碳链长度一定时,在哌啶环上不宜引入立体效应过大的取代基,这是由AgamOBP1结合口袋的大小决定的;与哌啶N相连的酰基作为氢键受体基团,对于化合物识别与结合AgamOBP1蛋白至关重要.     

Cloning,Sequence Analysis and Three-dimensional Structure Prediction of DNA Pol I from Thermophilic <Emphasis Type="Italic">Geobacillus</Emphasis> sp. <Emphasis Type="Italic">MKK</Emphasis> Isolated from an Iranian Hot Spring

Molecular phylogenetic analysis of a novel thermophilic eubacterium isolated from an Iranian hot spring using 16S rDNA sequence showed that the new isolate belongs to genera Geobacillus. DNA pol I gene from this isolate was amplified, cloned, sequenced, and the three-dimensional (3D) structure of deduced amino acid sequence was predicted. Sequence analysis revealed the gene is 2,631 bp long, encodes a protein of 876 amino acids with a calculated molecular mass of 99 kDa, and belongs to family A DNA polymerases. Comparison of 3′–5′exonuclease domain of Klenow fragment (KF) with corresponding region of newly identified DNA pol I (MF), the large fragment of Bacillus stearothermophilus DNA pol I (BF) and Klentaq1, revealed not only deletions in three regions compared to KF, but that three of the four critical metal-binding residues in KF (Asp355, Glu357, Asp424, and Asp501) are altered in MF as well. Predicted 3D structure and sequence alignments between MF and BF showed that all critical residues in the polymerase active site are conserved.     

A 3D‐QSAR Study of Celebrex‐Based Pdk1 Inhibitors Using Comfa Method

A 3D‐QSAR study of celebrex‐based compounds of PDK1 inhibitors using comparative molecular field analysis (CoMFA) was carried out. The structures of the compounds were obtained using quantum chemistry calculation. CoMFA calculations for a number of grouped subsets of compounds gave q² values of correlation in the range from 0 to 0.8. The low q² values should be mainly due to the narrow span of biological activity. Calculations for several subsets of 11–13 compounds gave high q² values, with 0.5–0.8. Factors affecting the results of the calculations are discussed. Calculated results with high q² values suggest that further chemical modifications of the compounds could lead to enhanced activity and could be an aid in the design of celebrex‐based cancer drugs.     

A Stereolithography‐Based 3D Printed Hybrid Scaffold for In Situ Cartilage Defect Repair

Damage to articular cartilage can over time cause degeneration to the tissue surrounding the injury. To address this problem, scaffolds that prevent degeneration and promote neotissue growth are needed. A new hybrid scaffold that combines a stereolithography‐based 3D printed support structure with an injectable and photopolymerizable hydrogel for delivering cells to treat focal chondral defects is introduced. In this proof of concept study, the ability to a) infill the support structure with an injectable hydrogel precursor solution, b) incorporate cartilage cells during infilling using a degradable hydrogel that promotes neotissue deposition, and c) minimize damage to the surrounding cartilage when the hybrid scaffold is placed in situ in a focal chondral defect in an osteochondral plug that is cultured under mechanical loading is demonstrated. With the ability to independently control the properties of the structure and the injectable hydrogel, this hybrid scaffold approach holds promise for treating chondral defects.     

A Prototype of a Volumetric Three-Dimensional Display Based on Programmable Photo-Activated Phosphorescence

A proof-of-principle prototype of a volumetric 3D-displaying system is demonstrated by utilizing the photo-activated phosphorescence of two long-lived phosphorescent metal-porphyrins in dimethyl sulfoxide (DMSO), a photochemically deoxygenating solvent. The first phosphorescent sensitizer, Pt(TPBP), absorbs a light beam with a wavelength of 635 nm, and the sensitized singlet oxygen is scavenged by DMSO. The second phosphorescent emitter, Pt(OEP), absorbs a light beam with a wavelength of 532 nm and visibly phosphoresces only in the deoxygenated zone generated by the first sensitizer. The phosphorescent voxels, 3D images, and animations are well-defined by the intersections of the 635-nm and 532-nm light beams that are programmable by tuning of the excitation-power densities, the beam shapes, and the kinetics. As a pivotal selection rule for the phosphorescent molecular couple used in this 3D-displaying system, their absorptions and emissions must be orthogonal to each other, so that they can be excited and addressed independently.     

Ionic Conduction of ANovel Comb Polvmer Electrolyte Based on Maleic Anhydride Copolymer with Oligo－oxyethylene Side Chains

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