Planar Quinary Cluster inside a Fullerene Cage: Synthesis and Structural Characterizations of Sc3NC@C-80-I-h

The endohedral fullerene Sc3NC@C-80-I-h has been synthesized and characterized; it has an unprecedented planar quinary cluster in a fullerene cage. It is also the first chemical compound in which the presence of an unprecedented (NC)(3-) trianion has been disclosed. The fascinating intramolecular dynamics in Sc3NC@C-80-I-h enables the whole molecule to display high polarity and promising ferroelectricity. This finding inspires the possibility that such a planar quinary cluster may be useful in constructing many other endohedral fullerenes.973 Program [2006CB300402, 2007CB815307]; NSFC [20821003, 20702053, 20973137, 20673088, 20425312, 20721001, 20423002]; Ministry of Science and Technology [2008ZX05013-004

Synthesis of micro-nano hierarchical structured LiFePO(4)/C composite with both superior high-rate performance and high tap density

Efforts were made to synthesize LiFePO(4)/C composites showing both high rate capability and high tap density. First, monoclinic phase FePO(4)center dot 2H(2)O with micro-nano hierarchical structures are synthesized using a hydrothermal method, which are then lithiated to LiFePO(4)/C also with hierarchical structures by a simple rheological phase method. The primary structures of FePO(4 center dot)2H(2)O are nanoplates with similar to 30 nm thickness, and the secondary structures of the materials are intertwisted micro-scale rings. The LiFePO(4)/C materials lithiated from these specially structured precursors also have hierarchical structures, showing discharge capacities of more than 120, 110, and 90 mAh g(-1) at rates of 5 C, 10 C and 20 C, respectively, and high tap density of 1.4 g cm(-3) as cathode materials for lithium ion batteries. Since tap density is an important factor that needs to be considered in fabricating real batteries in industry, these hierarchical structured LiFePO(4)/C moves closer to real and large-scale applications.National Science Foundation of China[20901062]; Central Universities[2082002

Synthesis of Novel Thiazolo[3,2-a]pyrimidine Compounds

A new class of thiazolo[3,2-a]pyrimidine compounds were synthesized by the reaction of 5-carbethoxyl-4-aryl-6-methyl-1,2,3,4-tetrahydropyrimidin-2-ones with dimethyl acetylenedicarboxylate. The reaction has the advantages of excellent yields and simple workup procedures. The products were characterized thoroughly by IR and NMR (H-1, C-13, COSY, HSQC and HMBC) together with elemental analysis. The X-ray crystallographic analysis of the 1,3-dipolar cycloaddition derivative of the title product provided the direct information for the structure of the product

Structure-chiroptical property relationship of kinetically labile camphor-derivative beta-diketone Yb(III) complexes: do the adducts coexist as diastereomers or not?

The present work examines the relationship between the crystal structures and chiroptical properties of four chiral Yb(III) complexes with camphor-derivative beta-diketone ligands by means of solid-state circular dichroism (CD) spectroscopy. For the seven-coordinate complexes, [Yb(H(2)O)(d-hfc)(3)] (I) and [Yb(H(2)O)(l-hfc)(3)] (II) (d/l-hfc(-) = 3-heptafluorobutyryl-(+)/(-)-camphorate), the Lambda- and Delta-diastereomers coexist in their crystals and no apparent bisignate couplets are observed in their solid-state CD spectra. A theoretical study indicates that the ground-state energy difference between the two diastereomers I and II is only 0.913 kcal mol(-1), which explains why they could coexist in a crystal environment with the ratio of 1:1. While, eight-coordinate complexes Delta-[Yb(TPPO)(2)(d-hfc)(3)]center dot CHCl(3)center dot 3C(6)H(12) (III) and Lambda-[Yb(TPPO)(2)(l-hfc)(3)]center dot CHCl3 center dot 3C(6)H(12) (IV) (TPPO = triphenylphosphine oxide) are enantiopure in the solid-state, and typically negative and positive exciton splitting patterns around 330 nm are observed in their solid-state CD spectra. The solid-state CD spectra of these four complexes are in accordance with their X-ray single-crystal analyses. Besides, their solution CD spectra show that no particular isomer predominates in solution.NSFC[20973136, 20773098, 20673069]; NSF of Shanxi province[2007011021

NMR Studies on Interactions between Diperoxovanadate and 1-Ethyl-1H-Imidazole

To understand the effects of organic ligands on the reaction equilibrium, interactions between a series of diperoxovanadate complexes [OV(O-2)(2)L](-) (L=D2O or HOD, the corresponding peroxovanadate species (bpV)) and [OV (O-2)(2)LL'](n-) {n=1-2; LL' =3-hydroxyl-picolinate (3-OH-pic), 2-(2'-pyridine)-imidazole (py-im), 1,10-phenanthroline (phen), the corresponding peroxovanadate species bpV(3-OH-pic), bpV(py-im), and bpV(phen)} and 1-ethyl-1H-imidazole (N-Et-im) in solution were explored using multinuclear (H-1, C-13, and V-51) magnetic resonance, COSY (con-elated spectroscopy), HSQC (heteronuclear single quantum coherence) and variable temperature nuclear magnetic responance (NMR) using 0.15 mol.L-1 NaCl ionic medium to mimic physiological conditions. Experimental results indicated that the reactivity of these four complexes with 1-ethyl-1H-imidazole decreased as follows: bpV > bpV(3-OH-pic)> bpV(py-im)> bpV(phen). The coordinating ability, the steric effect, and the molecular weight of these organic ligands affected the reaction equilibrium. A new six-coordinated peroxovanadate species [OV(O-2)(2)(N-Et-im)](-) was formed because of competitive coordination.National Natural Science Foundation of China [20772027, 20803020]; China Postdoctoral Science Foundation [20070410805]; Science Research Foundation of Ministry of Health & United Fujian Provincial Health ; Education Project for Tackling the Key Research [WKJ2008-2-036]; Health and Science and Technology of Xiamen, China [3502Z20051027

Targeted synthesis of an electroactive organic framework

A new strategy for targeted design and synthesis of an electroactive microporous organic molecular sieve (JUC-Z2) is described. Experiment demonstrated that such a targeted synthesis approach to achieve phenyl-phenyl coupling was a controllable process and predominately generated two-dimensional polymer sheets, significantly different from the traditional chemical or electrochemical oxidation methods to prepare conducting polymers. Successive self-assembly leads to a lamellar organic framework comprised of stacked polymer sheets with an hcb topology. JUC-Z2 was found to have a well-defined uniform micropore distribution (similar to 1.2 nm), a large surface area (BET = 2081 m(2) g(-1)) and high physicochemical stability (> 440 degrees C). After doping with I(2), JUC-Z2 exhibits typical p-type semiconductive properties. As the first example of an electroactive organic framework, JUC-Z2 possesses a unique ability of electrochemical ion recognition, arising from the synergistic function of the uniform micropores and the N-atom redox site.State Basic Research Project[2011CB808703]; NSFC[91022030, 20771041, 20773101, 20833005]; "111'' project[B07016]; Ministry of Science and Technology[2006DFA41190]; Jilin Science and Technology Department[20106021

An Intermetallic Au24Ag20 Superatom Nanocluster Stabilized by Labile Ligands

通讯作者地址: Zheng, NFAn intermetallic nanocluster containing 44 metal atoms, Au24Ag20(2-SPy)(4)(PhC C)(20)C-l2, was successfully synthesized and structurally characterized by single-crystal analysis and density funtional theory computations. The 44 metal atoms in the cluster are arranged as a concentric three-shell Au-12@Ag-20@Au-12 Keplerate structure having a high symmetry. For the first time, the co-presence of three different types of anionic ligands (i.e., phenylalkynyl, 2-pyridylthiolate, and chloride) was revealed on the surface of metal nanoclusters. Similar to thiolates, alkynyls bind linearly to surface Au atoms using their s-bonds, leading to the formation of two types of surface staple units (PhC C-Au-L, L = PhC C- or 2-pyridylthiolate) on the cluster. The co-presence of three different surface ligands allows the site-specific surface and functional modification of the cluster. The lability of PhC C- ligands on the cluster was demonstrated, making it possible to keep the metal core intact while removing partial surface capping. Moreover, it was found that ligand exchange on the cluster occurs easily to offer various derivatives with the same metal core but different surface functionality and thus different solubility.MOST of China 2011CB932403 2015CB932303 NSFC of China 21420102001 21131005 21390390 21227001 21333008 Academy of Finlan

Specific Release of Bacteriochlorophylls B800 of LH2 from Rhodobacter azotoformans Induced by Sodium Dodecyl Sulfate

The release behaviors of bacteriochlorophylls of peripheral light-harvesting complex LH2 from Rhodobacter azotoformans induced by sodium dodecyl sulfate (SDS) were investigated using absorption spectroscopy. The results indicated that bacteriochlorophylls of B800 band are released from their binding sites and transformed into free bacteriochlorophylls by incubating LH2 sample in 10 mmol.L-1 Tris-HCl (pH 8.0) buffer containing SDS of low concentration at room temperature. However, the bacteriochlorophylls of B850 band are not released. The dynamics of B800 release and free BChl formation induced by 0.08% (w/V) SDS can be well fitted by the monoexponential model. The rate constant of B800 release is nearly equal to that of free BChls formation. The release of both B800 and B850 of LH2 can be induced by high concentration SDS, simultaneously. The bacteriochlorophylls of B800 band can be completely transformed into free BChls, but not for B850. Although both of their release processes show monoexponential models in 1% SDS solution, the release rate constant of B850 is remarkably lower than that of B800 and close to that of free BChls formation.国家自然科学基金(No. 30970068)、国家科技基础条件平台建设(No. 2005DKA21209)、厦门大学近海海洋环境科学国家重点实验室高级访问学者基 金(No. MELRS0907)和山西省回国留学人员科研(No. 200713)资助项目

A molecular imprinting-based turn-on Ratiometric fluorescence sensor for highly selective and sensitive detection of 2,4-dichlorophenoxyacetic acid (2,4-D)

A novel molecular imprinting-based turn-on ratiometric fluorescence sensor was constructed via a facile sol-gel polymerization for detection of 2,4-dichlorophenoxyacetic acid (2,4-D) on the basis of photo induced electron transfer (PET) by using nitrobenzoxadiazole (NBD) as detection signal source and quantum dots (QDs) as reference signal source. With the presence and increase of 2,4-D, the amine groups on the surface of QDs@SiO2 could bind with 2,4-D and thereby the NBD fluorescence intensities could be significantly enhanced since the PET process was inhibited, while the QDs maintained constant intensities. Accordingly, the ratio of the dual-emission intensities of green NBD and red QDs could be utilized for turn-on fluorescent detection of 2,4-D, along with continuous color changes from orange-red to green readily observed by the naked eye. The as-prepared fluorescence sensor obtained high sensitivity with a low detection limit of 0.14 mu M within 5 min, and distinguished recognition selectivity for 2,4-D over its analogs. Moreover, the sensor was successfully applied to determine 2,4-D in real water samples, and high recoveries at three spiking levels of 2,4-D ranged from 95.0% to 110.1% with precisions below 4.5%. The simple, rapid and reliable visual sensing strategy would not only provide potential applications for high selective ultratrace analysis of complicated matrices, but also greatly enrich the research connotations of molecularly imprinted sensors. (C) 2016 Elsevier B.V. All rights reserved