Coordination chemistry of organometallic polydentate ligand Reactive chemistry of the tridentate ligand trans‐Fe(Ph2PQu‐P)2‐(CO)3 [PhzPQu=2‐diphenyl‐phosphino‐4‐methylquinoline] and molecular structure of [Fe(CO)3(μ‐Ph2PQu)2HgI]+ [HgI3]

Reaction of a new type of bidentate ligand PhPQu [PhPQu = 2‐diphenylphosphino‐4‐methylquinoline] with Fe(CO)₅ in butanol gave trans‐Fe(FpPQu‐P)(CO)₃ (1). Compound 1, which can act as a neutral tridentate organometallic ligand, was reacted with I B, II B metal compounds and a rhodium complex to give six binuclear complexes with Fe? M bonds, Fe(CO)₃ (μ‐Ph₂PQu)MX_n (2–7) [M= Zn(II), Cd(II), Hg(II), Cu(I), Ag(I), Rh(I)], and an ion‐pair complex [Fe(CO)₃ (μ‐Ph₂PQu)₂HgI][HgI₃]^? (8). The structure of 8 was determined by X‐ray crystallography. Complex 8 crystallizes in the space group P‐1 with a = 1.0758(3), b = 1.6210(4), c=1.7155(4)nm; a=75.60(2), β=71.81(2), γ=81.78(2)° and Z = 2 and its structure was refined to give agreement factors of R=0.050 and R_w = 0.057. The Fe‐Hg bond distance is 0.2536nm.     

Preparation, characterization and gas-sensitive properties of nano-crystalline Cr_2O_3-Fe_2O_3 mixed oxides

Ｆｅｒｒｉｃｏｘｉｄｅ(αＦｅ2Ｏ3),ｃｈｒｏｍｉｃｏｘｉｄｅ(αＣｒ2Ｏ3)ａｎｄｔｈｅｉｒｍｉｘｅｄｃｏｍｐｏｕｎｄｓｈａｖｅｉｍｐｏｒｔａｎｔａｐｐｌｉｃａｔｉｏｎｉｎｍａｎｙｆｉｅｌｄｓ.Ｆｏｒｉｎｓｔａｎｃｅ,ｔｈｅｙｃａｎｂｅｕｓｅｄａｓｃａｔａｌｙｓｔｓｆｏｒｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｗａｔｅｒｇａｓｓｈｉｆｔｒｅａｃｔｉｏｎ[1]ａｎｄｒｅｄｕｃｔｉｏｎｏｆＮＯｘｂｙＮＨ3[2],ａｓｒｅｆｒａｃｔｏｒｙｍａｔｅｒｉａｌｓ[3]ａｎｄｓｅｎｓｉｎｇｍａｔｅｒｉａｌｓ[4,5],ａｎｄｓｏｏｎ.Ｓｉｎｃ…     

X-ray Crystal Structure of a Mononuclear Copper (Ⅱ) Complex with Unusual Monodentate O-coordination of Carboxylate Group of Isonicotinate

Copperproteinsitesareassociatedwithavarietyofvitalbiologicalfunctions,includingelectrontransfer,anddioxygentransportandactivationl.ThelargemolecularweightandcomPlexnatureoftheproteinsmakedetailedstudiesoftheiractivesitesandchemistryverydifficult-Tobetterunderstandtheinherentcoordinationchemistryassociatedwiththeactivesite,syntheticanalogsaremostuseful2.Histidine(imidazole)playskeyrolesinthecatalyticfunctionsofalmostallofthemetalloenzymes.Therefore,complexeswithinddazoleligandsareofinterestast…     

Crystal Structure of (3S, 6S, 7R, 8R)-3,6-Bis-diphenylphosphino-1,4-dioxabicyclo〔3.3.0〕octane

1INTRoDUCTIONThetitlecompoundhasbeenfoundtobeaveryefficientchiralligandusedtoco-ordinatewithpalladiumformingcatalystsystemsforasymmetrichydroesterificationofnorborneneandstyrene.Intheseasymmetriccatalyticreactions,thechiralinduc-tionofthetitlecompoundisratherstronggivingveryhighoptica1yields(>9o%)ofproductstl3.Inordertostudytherelationshipoftheperformanceandthestructureofthisligand,itisimportanttodeterminethemolecularstructureofthechiraldiphos-phinecompound,whichwaspreparedbytheliteraturem…     

氮、氧为配位原子的铅(Ⅱ)混合配合物的稳定性研究Ⅳ.铅(Ⅱ)-芳香氮碱-苯烷基丙二酸体系

混合配体配合物中配体间的相互作用在金属酶化学及其生物识别过程中具有重要意^[1,2].以往的研究,主要针对具有部分填充的3d过渡金属离子与芳香氮碱、氨基酸或一元羧 配合物体系^[3,4].铅(Ⅱ)为非过渡的主族金属离子,我们在对其PbLA型配合物的研究时 ,配合物中也存在配体间的相互识别作用^[5～7].     

Synthesis, structure and magnetic properties of the S=1/2, one-dimensional antiferromagnet, Y5Re2O12

Single crystals of Y₅Re₂O₁₂ have been grown, and the crystal structure has been determined by X-ray diffraction. This compound crystallizes in space group C2/m with cell dimensions of a=12.4081(10) Å b=5.6604(5)Å, c=7.4951(6) Å, β=107.837(3)°, Z=2. The final refinement led to R1=0.0238, WR2=0.0459 for 1053 observed reflections with F>4σ(F₀). Edge-sharing ReO₆ octahedra form infinite linear [ReO₂O_4/2]_n chains along the b direction with alternating short and long Re-Re distances. Three crystallographically independent yttrium atoms surround O2 to form OY₄ tetrahedra, which share edges and corners in the ab plane to form a two-dimensional Y₅O₄ network which separates the [ReO₂O_4/2]_n magnetic chains. This compound is therefore isostructural with the series Ln₅Re₂O₁₂Ln=Gd-Lu, which have been known since 1969. The average Re oxidation state is +4.5 in the chains and a reasonable, if qualitative MO scheme results in one unpaired electron per Re dimer. Consistent with this, magnetic susceptibility data can be fitted to the one-dimensional antiferromagnetic Heisenberg model with S=1/2 and parameters J^intra/k=−89(1)K, g=2.15(4) and χ(TIP)=5(1)×10⁻⁴ emu/mol. There is no sign of long-range magnetic order down to 2 K. These results are contrasted with those for the isostructural Y₅Mo₂O₁₂.     

Selective functionalization at the small rim of calix[6]arene. Synthesis of novel non-symmetrical N3, N4 and N3ArO biomimetic ligands

Eight novel calix[6]arene-based biomimetic ligands for transition metal ions have been synthesized. They display a non-symmetrical N₃, N₄ or N₃ArO binding core that mimics enzyme active sites presenting histidine and tyrosine residues. The key step for their synthesis is the mono-alkylation at the small rim of the C_3v symmetrical trimethyl ether derivative of tBu-calix[6]arene with N-Boc-2-chloroethylamine to yield a novel calix[6]arene synthon. Its combined O-alkylation with a chloromethyl aromatic amine and N-deprotection or alkylation or reductive alkylation with a salicylaldehyde derivative yielded the calix[6]arene-based ligands with mixed N/O donors.     

共聚物配体交替结构与其催化活性关系的理论研究

本文采用以ASED-MO(含原子对排斥的EHMO法)为基础的结构自动优化的EHTOPT法及Monte-Carlo法, 对甲醇羰基化制乙酸催化剂的共聚物配体交替结构进行了理论研究。计算了AA, AB, BB, BA二聚反应的反应途径, 找出了过渡态, 并确定了反应活化势垒。在假设两反应频率因子相同的前提下, 求出竞聚率, 采用Monte-Carlo法模拟共聚物结构, 计算出共聚物配体中起催化活性的AB交替结构所占比率。比较不同共聚物配体的活性, 并研究了温度及单体配比对共聚物配体交替结构的影响。     

Protein-ligand binding free energy estimation using molecular mechanics and continuum electrostatics. Application to HIV-1 protease inhibitors

A method is proposed for the estimation of absolute binding free energy of interaction between proteins and ligands. Conformational sampling of the protein-ligand complex is performed by molecular dynamics (MD) in vacuo and the solvent effect is calculated a posteriori by solving the Poisson or the Poisson-Boltzmann equation for selected frames of the trajectory. The binding free energy is written as a linear combination of the buried surface upon complexation, SASbur, the electrostatic interaction energy between the ligand and the protein, Eelec, and the difference of the solvation free energies of the complex and the isolated ligand and protein, deltaGsolv. The method uses the buried surface upon complexation to account for the non-polar contribution to the binding free energy because it is less sensitive to the details of the structure than the van der Waals interaction energy. The parameters of the method are developed for a training set of 16 HIV-1 protease-inhibitor complexes of known 3D structure. A correlation coefficient of 0.91 was obtained with an unsigned mean error of 0.8 kcal/mol. When applied to a set of 25 HIV-1 protease-inhibitor complexes of unknown 3D structures, the method provides a satisfactory correlation between the calculated binding free energy and the experimental pIC5o without reparametrization.     

Highly substituted azulene dyes as multifunctional NLO and electron-transfer compounds

Two highly substituted azulene derivatives were synthesised by Pd-mediated dimerisation from the corresponding tolan species. One azulene derivative (2) has donor functionalities (dianisylaminophenyl and dianisylamino) in the 1-, 2-, 3- and 6-positions, while the other (1) has donors (dianisylaminophenyl) in the 2- and 6-positions and acceptors (nitrophenyl) in the 1- and 3-positions. Each azulene derivative shows strong bond length alternation in the solid state, determined by X-ray crystal analysis, and an intense CT band around 450-500 nm in its UV/Vis spectrum. The first-order hyperpolarisability of 1 and of 2 was measured by hyper-Rayleigh scattering and is about that of disperse red DR1. Both azulene derivatives show multiple oxidation processes. The intramolecular adiabatic ET behaviour of the mixed valence radical cations of 1 and of 2 was investigated by UV/Vis/NIR spectroelectrochemistry. The intervalence-CT band of 1(+) could be analysed by the Generalised Mulliken-Hush theory, which yields an electronic coupling V=1140 cm(-1) for the optically induced adiabatic hole transfer.