Synthesis and structure of (η-cyclopentadienyl)(η-(1-(η-cyclopentadienyl)-2-phenyl-3-methyl-1-nickelaindenyl)nickel - the first analogue of nickelocene with a nickelacyclopentadienyl ring

A new metallacyclic compound (η⁵-cyclopentadienyl)(η⁵-(1-(η⁵-cyclopentadienyl)-2-phenyl-3-methyl-1-nickelaindenyl)nickel was synthesised and characterised. Its molecular and crystal structure was determined by X-ray measurements. It crystallises from hexane:THF mixture in the monoclinic crystal system and the P2₁/c space group. This is the first example of the homometallic metallametallocene of nickel. Like in nickelocene the central nickel atom has 20 valence electrons, so the compound can be regarded as the first nickelacyclic analogue of nickelocene.     

A Robust Photocatalytic Hybrid Material Composed of Metal-Organic Cages and TiO2 for Efficient Visible-Light-Driven Hydrogen Evolution

The design of photochemical molecular devices (PMDs) for photocatalytic H₂ production from water is a meaningful but challenging subject currently. Herein, a Pd₂L₄ type metal-organic cage (denoted as MOC-Q2) is designed as a PMD, which consists of two catalytic centers (Pd²⁺) and four photosensitive ligands (L-2) with four pyridine anchoring groups. Subsequently, the MOC-Q2 is combined with TiO₂ to form TiO₂-MOC-Q2 hybrid materials with different MOC-Q2 contents by a facile sol-gel method, which have micro/mesoporous structures and large surface areas. The optimized TiO₂-MOC-Q2 (6.5 wt%) exhibits high H₂ production activity (7.9 mmol g⁻¹ h⁻¹ within 5 h) and excellent durability, giving a TON value of 23477 or 11739 (based on MOC-Q2 or Pd moles) after recycling for 7 rounds. By contrast, the pure MOC-Q2 only shows an ordinary photocatalytic H₂ production rate (0.84 mmol g⁻¹ h⁻¹ within 5 h) in the homogeneous system. It can be deduced that TiO₂ drives the photocatalysis and simultaneously acts as the structure promoter. This study presents a meaningful and distinctive attempt of a new approach for the design and development of MOC-based heterogeneous photocatalysts.     

微米尺寸二硫化钼层间化合物的电化学制备及其储镁性能

采用一种简便的电化学方法制备了有机阳离子(1-丁基-3-甲基咪唑阳离子,BMIM~+)插层的微米尺寸MoS_2层间化合物,并将其用作镁离子电池正极材料。所制备的MoS_2层间化合物(MoS_2-BMIM~+)具有扩大的层间距(0.98 nm),能有效降低Mg~(2+)的嵌入/脱出势垒,为存储Mg~(2+)提供了更多的活性位点,从而表现出显著提高的充电比容量和良好的倍率性能。MoS_2-BMIM~+在20 mA·g~(-1)电流密度下的充电比容量可达101.93 mAh·g~(-1)(约4倍于初始体相MoS_2)。我们进一步证明了这一方法同样适用于插层1-丁基-1-甲基吡咯烷双阳离子(Pyr~+_(14)),所得化合物的层间距为1.04 nm。     

基于NaYF_4∶Yb~(3+),Er~(3+)上转换发光纳米晶的复合微球组装及其光动力活性

采用微乳液法,以NaYF4∶Yb3+,Er3+纳米晶为发光基元,肽菁锌(Zn Pc)光敏分子与十八碳烯-马来酸酐共聚物(PMAO)为功能分子,一步组装获得了NaYF4-Zn Pc-PMAO复合微球,此微球同时具备成像与光动力活性功能,NaYF4可作为低生物背景的荧光成像剂,同时其上转换发光可以敏化Zn Pc用于光动力活性研究,PMAO分子经过简单的水解反应即可实现表面羧基功能化。TEM,Zeta电位与PL测试证实了微球的结构与性能。利用荧光共聚焦成像技术实现了对Hela细胞的发光成像;进一步通过单线态氧监测及980 nm光照下的MTT法细胞活性测试表明微球具有光动力活性功能。     

基于NaYF4:Yb3+,Er3+上转换发光纳米晶的复合微球组装及其光动力活性研究

采用微乳液法,以NaYF₄:Yb³⁺,Er³⁺纳米晶为发光基元,肽菁锌(ZnPc)光敏分子与十八碳烯-马来酸酐共聚物(PMAO)为功能分子,一步组装获得了NaYF₄-ZnPc-PMAO复合微球,此微球同时具备成像与光动力活性功能,NaYF₄可作为低生物背景的荧光成像剂,同时其上转换发光可以敏化ZnPc用于光动力活性研究,PMAO分子经过简单的水解反应即可实现表面羧基功能化。TEM,Zeta电位与PL测试证实了微球的结构与性能。利用荧光共聚焦成像技术实现了对Hela细胞的发光成像;进一步通过单线态氧监测及980 nm光照下的MTT法细胞活性测试表明微球具有光动力活性功能。     

1-[4-(二甲氨基)苯亚甲基氨基]-4-苯基硫脲的另一个手性对映体晶体结构

对-二甲氨基苯甲醛和苯基氨基硫脲缩合反应生成1-[4-(二甲氨基)苯亚甲基氨基]-4-苯基硫脲(DMB), 产物能从溶液中析出单一手性对映体晶体. 用单晶X射线衍射技术测定了它的绝对构型, 晶体属正交晶系, P2₁2₁2₁空间群, a＝0.7870(2) nm, b＝1.1560(2) nm, c＝1.6668(3) nm, V＝1.5164(5) nm³, Z＝4, D_c＝1.307 g/cm³, F(000)＝632, μ＝0.213 mm^－1, 2557个可观测点[I＞2s(I)]精修的最终残差因子: R＝0.0409, wR＝0.1061, Flack参数为0.00(9), 能够确定绝对构型. 化合物的晶体结构和大宗粉末样品的固体圆二色谱表明化合物在结晶过程中发生单一对映体的手性堆积.     

Synthesis of 2-Chloromethyl-1-(<Emphasis Type="Italic">p</Emphasis>-vinylphenyl)cyclopropane and Its Copolymerization with Styrene

A new polyfunctional monomer, 2-chloromethyl-1-(p-vinylphenyl)cyclopropane, was synthesized, and its radical copolymerization with styrene was performed. The copolymerization constants were determined, and the Alfrey–Price Q–e parameters were calculated. The photochemical cross-linking of the synthesized copolymer containing photosensitive groups (cyclopropane ring, chlorinated organic moiety) was studied. The copolymer exhibits relatively high photosensitivity (54 cm² J^–1) and can be used as a photosensitive base of negative photoresists.     

A stereo- and regio-specific addition of η3-trimethylsilylallyltitanium compound with aldehydes. A facile and stereocontrolled synthesis of E- and Z-terminal dienes

η³-Trimethylsilyallyltitanium compound, (η⁵-C₅H₅)₂Ti(η³-1-trimethylsilylallyl), reacts with aldehydes to give (±)-(R,S)-3-trimethylsilyl-4-hydroxy-1-alkenes in excellent yields, which can be deoxysilylated to either E- or Z-1,3-dienes.     

Synthesis and Crystal Structure of the One‐Dimensional Polymer Compound {[Ba(OTf)2(thf)3]2[Ba(OTf)2(thf)2]} (OTf = CF3SO3–) – Excerpts from a Three‐Dimensional Structure as an Access to New Materials?

Ba(CF₃SO₃)₂ reacts with the O‐donor ligand THF to yield the coordination compound {[Ba(OTf)₂(thf)₃]₂[Ba(OTf)₂(thf)₂]} ( 1 ) (OTf = CF₃SO₃^–). The title compound can be described as a one‐dimensional excerpt from the higher‐dimensional crystal structure of Ba(CF₃SO₃)₂, stabilized by THF. This example for the concept of formally “cutting out” structural elements from a three‐dimensional solid state compound confirms and can be compared to the case of the structural “genealogy tree” of BaI₂. This could be an efficient approach for new materials with highly anisotropic properties.     

Synthesis,Crystal Structure and Properties of Novel Composite Complex: [La(Nmp)4(H2o)4][HsiMo12O40]·2nmp·H2o

A new composite complex of [La(NMP)₄(H₂O)₄][HSiMo₁₂O₄₀]·2NMP·H₂O (NMP = N-methyl-2- pyrrolidone) was synthesized and characterized by IR, UV, ESR, TG-DTA and single crystal structural analysis. The water and organic ligands (NMP) coordinate directly with La(III) to form a dodecahedral complex and the SiMo₁₂O^4? ₄₀ anion is the counter ion. IR and X-ray analysis show that there is strong interaction between the polyoxometalate and organic donors. The complex is strongly photosensitive under irradiation with sunlight, resulting in a charge-transfer complex by oxidation of the N-methyl-2-pyrrolidone and reduction of the polyoxometalate. Low temperature ESR spectra indicate thermal electron delocalization among the Mo atoms in the title compound.     

On the synthesis of xenon(II) fluorostannates(IV)

The reaction between tin difluoride and an excess of xenon difluoride at 140°C yields two new xenon(II) fluorostannates(IV): 3XeF_2^·4SnF₄ and XeF_2^·2SnF₄. The 3:4 compound can be written as a molecular adduct of XeF₂ and the 1:2 compound. On the basis of vibrational spectra, the 1:2 compound can be formulated as a XeF⁺ salt with a polymeric anion.     

Stable Heterometallic Cluster-Based Organic Framework Catalysts for Artificial Photosynthesis

A series of stable heterometallic Fe₂M cluster-based MOFs ( NNU-31-M , M=Co, Ni, Zn) photocatalysts are presented. They can achieve the overall conversion of CO₂ and H₂O into HCOOH and O₂ without the assistance of additional sacrificial agent and photosensitizer. The heterometallic cluster units and photosensitive ligands excited by visible light generate separated electrons and holes. Then, low-valent metal M accepts electrons to reduce CO₂, and high-valent Fe uses holes to oxidize H₂O. This is the first MOF photocatalyst system to finish artificial photosynthetic full reaction. It is noted that NNU-31-Zn exhibits the highest HCOOH yield of 26.3 μmol g⁻¹ h⁻¹ (selectivity of ca. 100 %). Furthermore, the DFT calculations based on crystal structures demonstrate the photocatalytic reaction mechanism. This work proposes a new strategy for how to design crystalline photocatalyst to realize artificial photosynthetic overall reaction.     

An organic–inorganic polymer with Keggin-type polyoxoanions as building blocks: preparation,characterization and crystal structure of {H[Ba(DMF)6PMo12O40]·(dma)} n

A novel organic–inorganic polymer of {H[Ba(DMF)₆(PMo₁₂O₄₀)]·(dma)} _n (dma?=?dimethylamine, DMF?=?N,N-dimethylformamide) has been synthesized and characterized. Single-crystal X-ray structural analysis indicates that the title compound crystallizes in a monoclinic lattice, C2/c with a?=?22.336(5), b?=?12.798(3), c?=?21.498(4)?Å, β?=?99.77(3)°, Z?=?4, V?=?6065(2)?ų, D _c ?=?2.673?Mg?m^?3, F(000)?=?4620, R ₁?=?0.0600, wR ₂?=?0.1125. Crystal structural analysis reveals that Ba²⁺ ion lies in a distorted square antiprismatic environment with eight oxygen atoms, six from DMF molecules and two from adjacent polyanions. [Ba(DMF)₆]²⁺ ions coordinated to [PMo₁₂O₄₀]^3? building blocks form a 1D corrugated chain. The results of the single crystal X-ray diffraction and IR spectra show the metal cations are coordinated to Keggin clusters. The ESR spectra show that the title compound is strongly photosensitive towards sunlight. Cyclic voltammetry shows that the title compound undergoes five two-electron reversible reductions and the [PMo₁₂O₄₀]^3? anions are the active centers for electrochemical redox reactions in solution.     

A 3D Adenine-based Cd-MOF: Synthesis,Structure and Photoluminescent Sensing for an Aromatic Azo Compound

A new Cd-MOF containing the nucleobase adenine and multicarboxylates, Cd₂(tdc)₂(1H-ade)₂(H₂O) (H₂tdc = 2,5-thiophene carboxylic acid, 1H-ade = adenine), was synthesized successfully under hydrothermal condition and characterized by single-crystal X-ray diffraction, infrared spectrum, thermogravimetric analysis and photoluminescence. The two crystallographically unsymmetrical Cd atoms are bridged by 2,5-tdc ligands with (κ¹-κ¹)-(κ¹)-μ₃ and (κ¹–κ¹)–μ₂ modes into two dimensional extended layers, which are further pillared with the neutral ade molecules to form a 3D frameworks stabilized by extensive π ··· π interactions between imidazole-, pyrimidine- and thiophene-rings. Inspection of the structure reveals that the architecture can be simplified as a 3,4,5- connected networks with a Schläfli symbol of (6² · 8)(4² · 6³ · 8)(4² · 6⁵ · 8³). The photochemical property shows that the luminescent emission can be significantly quenched by aromatic azo compounds. The quenching effect coefficient (K_sv) for bis(4-imidazol-1-yl-phenyl)diazene is determined to be 4.1 × 10⁴ m ^–1, indicating the title compound as a potential fluorescent sensing materials.     

New phosphonium molybdate-promoted green,fast and selective catalytic procedure for the synthesis of trisubstituted imidazoles

The compound 1,1′-(ethane,1,2-diyl)ditriphenylphosphonium hexamolybdate dimethylsulfoxide {C₂H₄[P(C₆H₅)₃]₂}{Mo₆O₁₉}·SO (CH₃)₂ ( I ) was prepared, and ¹H-NMR, ¹³C-NMR, Fourier transform-infrared, differential scanning calorimetry and single crystal X-ray diffraction analysis were used to characterize the titled compound. Crystallographic data showed that compound I crystallized in the monoclinic crystal system in C2/c space group. The compound ( I ) was used for selective synthesis of 2,4,5-tri aryl imidazole derivatives under solvent-free conditions efficiently. Because of hindrance of the catalyst, the yields of products for aldehydes bearing para substituents are higher than the aldehydes bearing ortho substituents, and for aromatic aldehydes with meta substituents are very low.     

New sandwich-type polymeric potassium-dicyanoargentate(I) complex: synthesis,characterization and enzymatic activity

Coordination compounds containing dicyanoargentate(I) have remarkable biological potential due to their therapeutic antibacterial, antifungal, antibiofilm, and anticancer properties. In this study, a new dicyanoargentate(I)-based complex was synthesized and characterized by various procedures (elemental, thermal, FT-IR for complex) involving crystal analysis of the complex. In addition, the biological activity of this new compound on the acetylcholinesterase (AChE) enzyme, an important enzyme for the nervous system, was investigated. When the infrared (IR) spectrum of the complex is examined, the OH vibration peak resulting from H₂O molecules in the structure at 3948-3337 cm⁻¹ and at 2138 cm⁻¹, along with a CN peak coordinated to Ag, can be seen, indicating that the mass remaining in the thermal degradation of the complex at 1000 ◦ C is the weight corresponding to the metal mixture consisting of K+Ag (calc.: 68.06). The crystal method revealed that the complex has a sandwich-like, polymeric chemical structure with layers formed by K⁺ cations and [Ag(CN)₂H₂O]⁻ anions. Therefore, the AChE enzyme has potential therapeutic uses in improving ACh levels in brain cells, in reducing various side effects, and in improving cognitive impairment, especially in advanced Alzheimer’s disease patients. In this study, the activity of this newly synthesized complex on AChE was also investigated. As a result of this research, [Ag(CN)₂(H₂O)K] had 0.0282 ± 0.010 μM Ki values against AChE. The compound was therefore a good inhibitor for the AChE enzyme. This type of compound can be used for the development of novel anticholinesterase drugs.     

一种用于选择性检测苯乙烯的Zn-MOFs发光传感器

在溶剂热条件下合成了一种新型金属有机框架（MOF）{[Zn₂（tyia）₂（H₂O）₂]·H₂O}_n（1）,其中H₂tyia为5-（1H-1,2,4-三唑-1-基）间苯二甲酸。运用X射线单晶衍射分析其结构,通过元素分析、粉末X射线衍射、热重分析、固体荧光分析等手段对配合物1进行表征,研究了其与有机小分子相互作用的荧光特性。结果表明其能够对低浓度苯乙烯迅速做出反应,最低识别浓度为1.06 mmol·L^-1。此外,还对其传感机制进行了研究。     

Stable Heterometallic Cluster‐Based Organic Framework Catalysts for Artificial Photosynthesis

A series of stable heterometallic Fe₂M cluster‐based MOFs ( NNU‐31‐M , M=Co, Ni, Zn) photocatalysts are presented. They can achieve the overall conversion of CO₂ and H₂O into HCOOH and O₂ without the assistance of additional sacrificial agent and photosensitizer. The heterometallic cluster units and photosensitive ligands excited by visible light generate separated electrons and holes. Then, low‐valent metal M accepts electrons to reduce CO₂, and high‐valent Fe uses holes to oxidize H₂O. This is the first MOF photocatalyst system to finish artificial photosynthetic full reaction. It is noted that NNU‐31‐Zn exhibits the highest HCOOH yield of 26.3 μmol g^?1 h^?1 (selectivity of ca. 100 %). Furthermore, the DFT calculations based on crystal structures demonstrate the photocatalytic reaction mechanism. This work proposes a new strategy for how to design crystalline photocatalyst to realize artificial photosynthetic overall reaction.     

配位化合物Zn(Met)3(NO3)2·H2O(s)(Met=L-α-蛋氨酸)的低温热容及标准摩尔生成焓

利用精密绝热热量仪测定了化合物配合物Zn(Met)₃(NO₃)₂·H₂O (s) (Met=L-α-蛋氨酸)在78-371 K温区的摩尔热容. 通过热容曲线解析, 得到了该配合物的起始脱水温度为T_D=325.10 K. 将该温区的摩尔热容实验值用最小二乘法拟合得到了摩尔热容(C_p)对约化温度(T)的多项式方程, 由此计算得到了配合物的舒平热容值和热力学函数值. 基于设计的热化学循环, 选择100 mL of 2 mol·L^-1 HCl为量热溶剂, 利用等温环境溶解-反应热量计, 得到了298.15 K配合物的标准摩尔生成焓为Δ_fH_m⁰[Zn(Met)₃(NO₃)₂·H₂O(s),s]=-(1472.65±0.76) J·mol^-1.     

Non-chair six-membered-ring conformations. Preference for a twist-boat (or skew) structure in α- -sorbopyranose derivatives

The conformational preferences for 2,3-O-isopropylidene-α- -sorbopyranose derivatives 3–6 were determined by using ¹H NMR data and empirical force field calculations. Proton NMR studies of 3–6 indicate that a twist-boat (or skew) conformation (³S₀) prevails over possible chair forms for each compound. Force-field calculations (MM2, MNDO, AM1) on a model 2,3-O-isopropylidene-α- -sorbopyranose system (18) indicate that the ³S₀ conformation is among the low-energy structures. X-Ray crystallographic analysis of α- -sorbopyranose sulfamate 3, a compound with potent anticonvulsant activity, demonstrates that the ³S₀ skew conformation is manifested in the solid state, as well.