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Recognition of amino acids and anions by a Zn(Ⅱ)-methylazacalix[4]pyridine complex

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Science China Chemistry 2009年第10期52卷 1639-1645页

作者： GONG HanYuan, WANG DeXian, HUANG ZhiTang & WANG MeiXiang beijing national laboratory for molecular sciences, CAS laboratory of molecular Recognition and Function, Institute of Chemistry, Chinese Academy of sciences, beijing 100190, China beijing national laboratory for molecular sciences CAS Laboratory of Molecular Recognition and Function Institute of Chemistry Chinese Academy of Sciences Beijing China

As a powerful macrocyclic host molecule with unique conformation and cavity structure that are fine-tuned by the bridging nitrogen atoms, methylazacalix[4]pyridine (MACP-4) has been shown to selectively recognize Zn2+ and form stable Zn(Ⅱ)-MACP-4 complexes both in solid state and solution with an association constant up to 5.97 (logKs). The molecular recognition of Zn(Ⅱ)-MACP-4 complexes towards various amino acids and anions with different geometry was investigated by using the spectral titration methods and X-ray analysis. The Zn(Ⅱ)-MACP-4 complex was found to recognize the 17 amino acids tested with the association constant up to 3.97 (logKs). On the other hand, the Zn(Ⅱ)-MACP-4 complex selectively interacted with anions and the maximum association constant of 3.9 (logKs) was obtained.

关键词： Zn(Ⅱ)-MACP-4 complex amino acids anions recognition

High-resolution photofragment translational spectro- scopy for the UV photodissociation of C_2H_5I

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Science China Chemistry 2007年第4期50卷 476-482页

作者： BI WeiBin, XU XiLing, HUANG JianGou, XIAO DaoQing & ZHU QiHe beijing national laboratory for molecular sciences, State Key laboratory of molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of sciences, beijing 100080, China beijing national laboratory for molecular sciences State Key Laboratory of Molecular Reaction Dynamics Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

The photodissociation of ethyl iodide at 279.71, 281.73, 304.02 and 304.67 nm has been studied on our new mini-photofragment translational spectrometer with a total flight path of only 5 cm. Some vibra-tional peaks are firstly resolved in the TOF spectra of I*(2P1/2) and I(2P3/2) channels. These vibrational peaks are assigned to the excitation states (ν2 = 0, 1, 2,…) of the umbrella mode (ν2, 540 cm-1) of the photofragment C2H5, and the distribution of the vibrational states is obtained. The dissociation energy has been determined to be D0(C-I)=2.314 ± 0.03 eV. The energy partitioning of the available energy (Eavl=ET+Eint=ET+EV,R) calculated from our experimental data E int /E avl= 22.1% at 281.73 nm, 22.4% at 304.02 nm for the I* channel, and E int /E avl= 25.2% at 279.71 nm, 25.9% at 304.67 nm for the I channel, seem to be more reliable.

关键词： photofragment translational spectroscopy C_2H_5I photodissociation vibrational state distribution energy partitioning dissociation energy

Methanol as a probe to investigate the relationship between the secondary electron donor TyrZ and the substrate water molecules in active photosystem Ⅱ

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Chinese Science Bulletin 2010年第9期55卷 809-813页

作者： BAO Han, ZHANG ChunXi, REN YaNan & ZHAO JingQuan laboratory of Photochemistry, beijing national laboratory of molecular sciences, Institute of Chemistry, Chinese Academy of sciences, beijing 100190, China laboratory of Photochemistry Beijing National Laboratory of Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing China

The secondary electron donor, TyrZ, is implicated in tuning the primary charge separation and the water oxidation in active pho-tosystem II (PSII). Two types of mechanisms have been proposed to explain the function of TyrZ. One is that TyrZ tunes the water oxidation through the direct interaction with substrate water molecules; the other is that TyrZ is located in a hydrophobic envi-ronment without interacting with H2O, and controls the water oxidation by tuning the strength of the hydrogen bond between TyrZ and His190. Here, methanol was used as a probe to study the possible relationship between TyrZ and H2O by monitoring the TyrZ oxidation and TyrZ· reduction at cryogenic temperatures with electron paramagnetic resonance spectroscopy. The oxidation of TyrZ and reduction of TyrZ· in both S2 and S0 states at 10 K were accelerated by addition of a small amount of methanol (6%). Theoretical studies indicate that Tyr oxidation becomes more difficult if it interacts directly with the methanol molecule; while the decrease of the polarity of its environment accelerates the oxidation of Tyr. Accordingly, CH3OH does not directly interact with TyrZ in active PSII, and the accelerative effect of methanol is caused by the strength increase of the hydrogen bond between TyrZ and His190, resulting from the decrease of polarity of their environment after the displacement of H2O by CH3OH inside PSII. Considering the similarity between methanol and water, the results in this study support the model in which TyrZ does not interact with H2O in active PSII.

关键词： photosystem Ⅱ secondary electron donor TyrZ methanol water electron paramagnetic resonance

Organic single crystals or crystalline micro/nanostructures: Preparation and field-effect transistor applications

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Science China Chemistry 2010年第6期53卷 1225-1234页

作者： FU XiaoLong,WANG ChengLiang,LI RongJin,DONG HuanLi & HU WenPing beijing national laboratory for molecular sciences,Key laboratory of Organic Solids,Institute of Chemistry,Chinese Academy of sciences,beijing 100190,China beijing national laboratory for molecular sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing China

Organic single crystals hold great promise for the development of organic semiconductor materials,because they could reveal the intrinsic electronic properties of these materials,providing high-performance electronic devices and probing the structureproperty *** article reviews the preparation methods for organic single crystals or crystalline micro/nanostructures,including vapor phase growth methods and solution-processed methods,and summarizes a few methods employed in the fabrication of field-effect transistors along with dozens of examples concerning both small molecules and polymers with high field-effect performance.

关键词： organic single crystal physical vapor transport (PVT) solution-processed technique field-effect transistors (FETs) micro/nanostructures

Cellulose conversion to polyols on supported Ru catalysts in aqueous basic solution

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Science China Chemistry 2010年第7期53卷 1476-1480页

作者： DENG TianYin,SUN JiYing & LIU HaiChao beijing national laboratory for molecular sciences,State Key laboratory for Structural Chemistry of Stable and Unstable Species Green Chemistry Center,College of Chemistry and molecular Engineering,Peking University,beijing 100871,China beijing national laboratory for molecular sciences State Key Laboratory for Structural Chemistry of Stable and Unstable Species Peking University Beijing China Green Chemistry Center College of Chemistry and Molecular Engineering Peking University Beijing China

It is of great significance and challenge to achieve direct conversion of cellulose to specific polyols,e.g.,ethylene glycol and propylene *** such selective conversion,a novel one-pot approach was studied by combination of alkaline hydrolysis and hydrogenation on supported Ru catalysts.A wide range of bases including solid bases,e.g.,Ca(OH)2 and La2O3,and phosphate buffers were examined in the cellulose reaction in water,and the cellulose conversions and polyol products depended largely on the basicity or pH values in the aqueous *** glycol,1,2-propanediol,and especially 1,2,5-pentanetriol were obtained with selectivities of 15%,14% and 22%,respectively,at 38% cellulose conversion at pH 8 in phosphate buffer *** preliminary results provide potentials for efficient conversion of cellulose to targeted polyols by using the advantages of bases.

关键词： cellulose polyols Ru catalysts solid bases aqueous basic solutions

Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M = Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

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Science China Chemistry 2007年第3期50卷 308-317页

作者： ZHANG Wen, ZHAO Fei, LIU Tao & GAO Song beijing national laboratory for molecular sciences, State Key laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and molecular Engineering, Peking University, beijing 100871, China beijing national laboratory for molecular sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing China

A series of 1D nickel(II)/zinc(II)-lanthanide(III) coordination polymers, [M(μ-L)2Ln(NO3)3]n·solvents (HL = bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1·NiGd), Tb (2·NiTb), Dy (3·NiDy), Ho (4·NiHo), Y (5·NiY); M = Zn, Ln = Gd (6·ZnGd), Tb (7·ZnTb), Dy (8·ZnDy), Ho (9·ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293 K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1―9, where weak ferromagnetic interaction is found in 1·NiGd, ferromagnetic interaction in 2·NiTb and 3·NiDy, and antiferromagnetic interaction in 4·NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.

关键词： nickel lanthanide 3d-4f coordination polymer magnetic property

Synthesis and photophysical properties of Ir~Ⅲ-Ln~Ⅲ(Ln=Nd,Yb,Er) bimetallic complexes containing bipyrimidines as bridging ligands

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Science China Chemistry 2009年第11期52卷 1808-1813页

作者： CHEN FangFang,JIANG WeiLi,LOU Bin,BIAN ZuQiang & HUANG ChunHui beijing national laboratory for molecular sciences,State Key laboratory of Rare Earth Materials Chemistry and Applications,College of Chemistry and molecular Engineering,Peking University,beijing 100871,China beijing national laboratory for molecular sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing China

Bipyrimidines have been chosen as(N^N)(N^N) bridging ligands for connecting metal ***Ⅲ-LnⅢ(Ln = Nd,Yb,Er) bimetallic complexes [Ir(dfppy)2(μ-bpm)Ln(TTA)3]Cl were synthesized by using Ir(dfppy)2(bpm)Cl as the ligand coordinating to lanthanide complexes Ln(TTA)3·*** stability constants between Ir(dfppy)2(bpm)Cl and lanthanide ions were measured by fluorescence *** obvious quenching of visible emission from IrⅢ complex in the IrⅢ-LnⅢ(Ln = Nd,Yb,Er) bimetallic complexes indicates that energy transfer occurred from IrⅢ center to *** emissions from NdⅢ,YbⅢ,and ErⅢ were obtained under the excitation of visible light by selective excitation of the IrⅢ-based *** was proven that Ir(dfppy)2(bpm)Cl as the ligand could effectively sensitize NIR emission from NdⅢ,YbⅢ,and ErⅢ.

关键词： bipyrimidine IrⅢ-LnⅢ bimetallic complexes stability constant NIR emission excitation of visible light

Periodic tables of diatomic and triatomic molecules

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Science China Chemistry 2012年第6期55卷 618-625页

作者： KONG FanAo & WU WeiQiang beijing national laboratory for molecular sciences, Institute of Chemistry, Chinese Academy of sciences, beijing 100190, China beijing national laboratory for molecular sciences Institute of Chemistry Chinese Academy of Sciences Beijing China

The Mendeleev periodic table of atoms is one of the most important principles in natural science. However, there is shortage of analog for molecules. Here we propose two periodic tables, one for diatomic molecules and one for triatomic molecules. The form of the molecular periodic tables is analogous to that of Mendeleev periodic table of atoms. In the table, molecules are classified and arranged by their group number G, which is the number of valence electrons, and the periodic number P, which represents the size of the molecules. The basic molecular properties, including bond length, binding energy, force constant, ionization potential, spin multiplicity, chemical reactivity, and bond angle, change periodically within the tables. The periodicities of diatomic and triatomic molecules are thus revealed. We also demonstrate that the periodicity originates from the shell-like electronic configurations of the molecules. The periodic tables not only contain free molecules, but also the "virtual" molecules present in polyatomic molecules. The periodic tables can be used to classify molecules, to predict unknown molecular properties, to understand the role of virtual molecules in polyatomic molecules, and to initiate new research fields, such as the periodicities of aromatic species, clusters, or nanoparticles. The tables should be of interest not only to scientists in a variety of disciplines, but also to undergraduates studying natural sciences.

关键词： molecular periodicity – periodic table – diatomic molecules – triatomic molecules – molecular property

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Electron structure and substituent effects in o-,m-,p-IC_6H_4OCH_3 iodoanisoles

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Science China Chemistry 2009年第11期52卷 1932-1937页

作者： TONG ShengRui,WANG WeiGang,MA ChunPing,GE MaoFa & WANG DianXun beijing national laboratory for molecular sciences(BNLMS),State Key laboratory for Structural Chemistry of Unstable and Stable Species,Institute of Chemistry,Chinese Academy of sciences,beijing 100190,China beijing national laboratory for molecular sciences (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing China

The electronic structures and substituent effects in o-,m-,and p-iodoanisoles have been investigated by ultraviolet photoelectron spectroscopy(UPS).The observed UPS bands were analyzed by combining empirical arguments and theoretical *** to the electron-donating nature of both iodoand methoxy substituents,the first ionization potentials of the three iodoanisoles are lower than those of iodobenzene and *** presence of the two substituents in iodoanisoles leads to an electronrich structure,which might contribute to the observed high reactivity of iodoanisoles in a number of organic reactions.

关键词： electronic structures substituent effects ultraviolet photoelectron spectroscopy reactivity