A novel three-dimensional (3D) silver(I) coordination polymer, namely [Ag2(dmtrz)2]n (1) (Hdmtrz=3,5-dimethyl-1H,1,2,4-triazole), was synthesized through diffusion method. 1 was characterized by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis (TGA) and single-crystal X-ray diffraction. 1 crystallizes in the orthorhombic system, space group Iba2 with a=12.5026(10), b=7.6026(6), c=18.8981(17), V=1796.3(3)3, Z=6, Mr=407.98, Dc=2.263 g·cm-3, μ=3.252 mm-1, F(000)=1176, the final R=0.0304 and wR=0.0634 for 1310 observed reflections (I > 2σ(I)). In the structure of 1, silver(I) centers are triconnected to dmtrz ligands, forming the (3,3)-connected 3D coordination polymer with a 6.102 topology. The luminescence property of 1 was also studied in solid state at room temperature.
A series of Co/Mg–Al oxide samples,CoMgAl-x(x=(Mg+Co)/Al molar ratio of 1–5),were prepared by the self-combustion method followed by H2reduction.The catalytic performance and stability of the samples were studied in dry reforming of CH4.XRD and H2-TPR characterization results showed that the reduced CoMgAl-x samples mainly consisted of solid solution and spinel phases with cobalt particles.The spinel phases contained Co3O4 and Con Mg1-n Al2O4(0≦n≦1)varying with the(Mg+Co)/Al ratio.The effect of (Mg+Co)/Al molar ratio on the catalytic behavior was investigated in detail and CoMgAl-3 exhibited the highest catalytic activity and stability among the catalysts studied.
Wen-Jia CaiLin-Ping QianBin YueXue-Ying ChenHe-Yong He
Improvement of the low-cost transition metal electrocatalyst used in sluggish oxygen evolution reaction is a significant but challenging problem. In this study, ultrafine Fe-modulated Ni nanoparticles embedded in a porous Ni-doped carbon matrix were produced by the pyrolysis of zirconium metal–organic–frameworks, in which 2,2′-bipyridine-5,5′-dicarboxylate operating as a ligand can coordinate with Ni^(2+) and Fe^(3+). This strategy allows formation of Fe-modulated Ni nanoparticles with a uniform dimension of about 2 nm which can be ascribed to the spatial blocking effect of ZrO_(2). This unique catalyst displays an efficient oxygen evolution reaction electrocatalytic activity with a low overpotential of 372 mV at 10 mA·cm^(–2) and a small Tafel slope of 84.4 mV·dec^(–1) in alkaline media. More importantly, it shows superior durability and structural stability after 43 h in a chronoamperometry test. Meanwhile, it shows excellent cycling stability during 4000 cyclic voltammetry cycles. This research offers a new insight into the construction of uniform nanoscale transition metals and their alloys as highly efficient and durable electrocatalysts.
Activated by methylaluminoxane, mononuclear bis(hydroxyindanone-iminate)nickel complexes Ni[ArN == CC_2H_3(CH3)C_6H_2(R)O]_2 (Ar = 2,6-i-Pr2C6H3, R = Me (1), R = Cl (2), and R = H (3)) showed good activity for the styrene polymerization. The effect of many reaction parameters including the Al/Ni ratio, tempera- ture, and reaction time on catalytic activities of catalytic systems and the molecular weights of the ob- tained polystyrene was ascertained. The highest activity of 1.34×105 g(PS)·mol^(-1)(Ni)·h^(-1) was obtained under the optimum reaction condition. The 13C NMR spectra of the polymers revealed that the polymer was isotactic-rich atactic polystyrene. And the coordination mechanism was confirmed by the analyses of the polymer chain end-groups.
Ordered mesoporous aluminosilicate Al-SBA-15 materials with cage-like macropores have been synthesized by using micrometer-sized aluminum balls as an Al source,tetraethyl orthosilicate(TEOS) as a silica source,and triblock copolymer Pluronic P123 as a template.The resulting materials were fully characterized by XRD,N2 adsorption,SEM,TEM,ICP-AES,and 27Al MAS-NMR.The products(Al-SBA-15) have ordered two-dimensional(2-D) hexagonal mesostructures(space group p6mm).The calcined Al-SBA-15 materials exhibit disordered macropores with diameters of about 70―80 nm and ordered mesopores with a diameter of ～5 nm,a BET surface area of about 500 m2/g,Si/Al ratio of 40―80,and a ratio of tetrahedral Al to octahedral Al sites of about 2:1.This combination of properties gives these materials potential applications in areas such as adsorption,catalysis and separation.
This paper focuses on the group of metalloproteins/metalloenzymes in the acetyl-coenzyme A synthesis pathway of anaerobic microbes called Wood-Ljungdahl pathway,including formate dehydrogenase (FDH),corrinoid iron sulfur protein (CoFeSP),acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH). FDH,a key metalloenzyme involved in the conversion of carbon dioxide to methyltetrahydrofolate,catalyzes the reversible oxidation of formate to carbon dioxide. CoFeSP,as a methyl group transformer,accepts the methyl group from CH3-H4 folate and then transfers it to ACS. CODH reversibly catalyzes the reduction of CO2 to CO and ACS functions for acetyl-coenzyme A synthesis through condensation of the methyl group,CO and coenzyme A,to finish the whole pathway. This paper introduces the structure,function and reaction mechanisms of these enzymes.
ZHU XiaoFei1 & TAN XiangShi1,2 1 Department of Chemistry,Fudan University,Shanghai 200433,China
A new 1,8-naphthalimide derivative was prepared in which the C-4 position was substituted by pyridin-4-ol.This derivative shows good gelation property that can gelate most of polar solvents.As an achiral molecule,helical fibre morphology was observed when the compound gelated acetone solvent.When 0.5 eq of D-tartaric acid or L-tartaric acid was added to the gel,the helical morphology was changed from left-handed to right-handed structure.This result was further proved by circular dichroism measurement.FT-IR experiment showed the formation of intermolecular H-bond between the gelator and tartaric acid.The photophysical properties of gelator had no difference before and after addition of tartaric acid;whereas the lamellar structure was varied by addition of tartaric acid.
CAO XinHuaZHANG MingMingLIU KeYinMAO YueYuanLAN HaiChuangLIU BinYI Tao
