Solution self-assembly, spontaneous deprotonation, and crystal structures of bipyrazolate-bridged metallomacrocycles with dimetal centers

A series of nanosized cavity-containing bipyrazolate-bridged metallomacrocycles with dimetal centers, namely, {[(bpy)M]8L4}(NO3)8 [L=3,3',5,5'-tetramethyl-4,4'-bipyrazolyl, Pd, Pt; 1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene), Pd; and 1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbiphenyl, Pd], {[(phen)M]8L4}(NO3)8 [L=3,3',5,5'-tetramethyl-4,4'-bipyrazolyl, Pd, Pt; 1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene, Pd; and 1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbiphenyl, Pd], {[(bpy)Pd]6L3}(NO3)6 [L=1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene,], {[(phen)Pd]6L3}(NO3)6 [L=1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene,], {[(bpy)Pd]4L2}(NO3)4 [L=1,3-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene, and 1,2-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene,], and {[(phen)Pd]4L2}(NO3)4 [L=1,3-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene, and 1,2-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene,] (where bpy=2,2'-bipyridine and phen=1,10-phenanthroline) have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the 1H-bipyrazolyl ligands in aqueous solution. These complexes, with weak Pd(II)...Pd(II) or Pt(II)...Pt(II) interactions, have been characterized by elemental analysis, 1H and 13C NMR, cold-spray ionization or electrospray ionization mass spectrometry, UV-visible spectroscopy, and luminescence spectroscopy. Complexes and have also been characterized by single-crystal X-ray diffraction analysis.     

Ln2O3/Al2O3催化酯化合成邻苯二甲酸二辛酯

Ｌｎ_２Ｏ_３／Ａｌ_２Ｏ_３催化酯化合成邻苯二甲酸二辛酯陈其瑞，张凤美，罗明润，焦肇林（安徽师范大学化学系，芜湖２４１０００）关键词稀土氧化物，担载催化剂，催化酯化，邻苯二甲酸二辛酯邻苯二甲酸二（２－乙基己醇用酯（Ｄｉｏｃｔｙｌｐｈｔｈａｌａｔｅ）是一...     

Studies on synthesis and molecular dynamics simulation of dendrimers containing amino acids and peptides

A series of poly(ether-amide) dendrimers with amino acids and peptides as the peripheral functional groups was synthesized, and their structures were confirmed by nuclear magnetic resonance (NMR) and electrospray ionization-mass spectrometry (ESI-MS) spectrometry. Molecular dynamics simulation of the peptide dendrimers in solution was performed, indicating that, the prior conformations of the dendrimers were atom number dependent, i.e., with the increases of the atom number, the prior conformations were more spherical. Also, the amino acid α-C atom radial distribution indicated that, with larger peripheral groups, more back-folding of the dendrimers occurred. __________ Translated from Acta Chimica Sinica, 2007, 65(1): 21–26 [译自: 化学 通报]     

Syntheses,Characterization and Crystal Structures of Three Structurally Similar Dinuclear Schiff Base Cadmium(II) Complexes with Bridging Azide or Thiocyanate Ligands

Three novel Schiff base cadmium(II) complexes, derived from the end‐on (μ‐1,1‐N₃) azide or end‐to‐end (μ‐1,3‐NCS) thio cyanate bridges and similar tridentate Schiff base ligands, have been synthesized under similar synthetic procedures and their crystal structures determined by X‐ray diffraction methods. They are the dinuclear double end‐on azide‐bridged [Cd₂(L1)₂(N₃)₂(μ‐1,1‐N₃)₂] ( 1 ), the dinuclear double end‐on azide‐bridged [Cd₂(L2)₂(N₃)₂(μ‐1,1‐N₃)₂] ( 2 ), and the dinuclear double end‐to‐end thiocyanate‐bridged [Cd₂(L3)₂(NCS)₂(μ_1,3‐NCS)₂] ( 3 ), where L1, L2 and L3 are three similar tridentate Schiff bases obtained by condensation of 2‐pyridylaldehyde with N,N‐diethylethane‐1,2‐diamine, of 2‐pyridylaldehyde with N‐isopropylethane‐1,2‐diamine, and of 2‐pyridylaldehyde with N,N‐dimethylpropane‐1,3‐diamine, respectively. Each cadmium(II) centre in the complexes is in a distorted octahedral coordination. There is a crystallographic inversion centre in each of the complexes. The similar small ligands used as the secondary ligands in the preparation of the cadmium(II) complexes with similar Schiff bases can result in similar structures.     

A facile route to vinyl- and arylphosphonates by vinyl and aryl radical trapping with (MeO)3P

The generation of vinyl or aryl radicals under classical, thermal AIBN/n-Bu(3)SnH conditions at 80 degrees C in the presence of an excess of (MeO)(3)P gives rise to the corresponding vinyl- or arylphosphonates in good yields. This approach complements the photochemical reactions of the same systems previously used. Reactions with the individual stereoisomers of MeCH=CHMeBr (thermal AIBN/n-Bu(3)SnH conditions) afford a radical-equilibrated 96/4 E/Z ratio of vinylphosphonates. Substitution of (TMS)(3)SiH for n-Bu(3)SnH yields an approximately 1/1 ratio of separable E and Z vinylphosphonate diastereomers.     

咪唑-金属配合物的合成、性质及其与DNA的作用机理

Three hexakis（imidazole）metallo complexes of Co, Cd and Ni were synthesized and spectroscopically characterized. The crystal and molecular structures have been determined by X-ray crystallography analysis. The metal ions have an octahedral geometry with the MN6 chromophore. The electrochemical experimental results indicate that both [Co（Im）6]C12·2HCl·2H2O （1） and [Ni（Im）6]C12·4H2O （3） [Im=imidazole] could interact with DNA mainly by intercalation.     

微波辐射下LaNaY沸石的水热交换反应

报道微波辐射应用于ＮａＹ沸石与Ｌａ（ＮＯ＿３）＿３溶液的离子交换反应，结果表明微波辐射可提高Ｌａ￣＋的交换度，缩短交换时间。     

Structures and energies of coadsorbed CO and H2 on Fe5C2(001), Fe5C2(110), and Fe5C2(100)

Density functional theory calculations have been carried out on the CO/H2 coadsorption on the (001), (110), and (100) surfaces of Fe5C2 for the understanding of the Fischer-Tropsch synthesis (FTS) mechanism. The stable surface species changes with the variation of the H2 and CO coverage. Along with dissociated hydrogen and adsorbed CO in 2-, 3-, and 4-fold configurations, methylidyne (C(s)H) (C(s), surface carbon), ketenylidene (C(s)CO), ketenyl (C(s)HCO), ketene (C(s)H2CO), and carbon suboxide (C(s)C2O2) are computed as thermodynamically stable surface species on Fe5C2(001) and Fe5C2(110) containing both surface iron and carbon atoms. These surface carbon species can be considered as the preliminary stages for FTS. On Fe5C2(100) with only iron atoms on the surface layer, the stable surface species is dissociated hydrogen and CO with top and 2-fold configurations. The bonding nature of these adsorbed carbon species has been analyzed.     

Crosslinking polydopamine/cellulose nanofibril composite aerogels by metal coordination bonds for significantly improved thermal stability,flame resistance,and thermal insulation properties

Cellulose nanofibril (CNF) aerogels have attracted great interests in recent years due to the low cost, sustainability and biocompatibility of raw CNF. However, the poor thermal stability and flammable feature of CNF aerogels have limited their wider applications. In this paper, polydopamine/CNF composite aerogels with good comprehensive properties are fabricated by modification of CNF with polydopamine and metal coordination bonds crosslinking. The microstructure and properties of composite aerogels are thoroughly characterized by a variety of tests. It is found that the microstructure of aerogels are more regular and the compressive strength of aerogels are enhanced by the incorporation of polydopamine and Fe³⁺ crosslinking. Importantly, the thermal stability and flame resistance of aerogels are significantly improved, which permit the application of composite aerogels in high-temperature thermal insulation. In addition, the reversible characteristic of metal coordination bonds allows the water induced healing of fractured composite aerogels. This study is expected to provide information for future development of green and high-performance aerogels.

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The effect of the third component on butadiene–propylene alternating copolymerization catalyzed by vanadium–aluminum system

The effects of five ethers and four AliBu₂OR's with varied R' on butadiene–propylene alternating copolymerization were investigated. It was found that by adding the proper third component, both the conversion and the catalytic efficiency could be increased. The effect of the third component on the valence state of vanadium ion was also studied. A model of the active center of the ternary-component catalyst system was proposed.