Monomeric and polymeric structures of oxovanadium(IV) complexes with Schiff base ligands derived from (R,R)-2,4-pentanediamine: Synthesis and crystal structure

New tetradentate Schiff base–oxovanadium(IV) complexes which have electron donating or withdrawing groups at the 5-position of the salicylaldehyde moieties, [VO{Xsal-(R,R)-2,4-ptn}] (H₂{Xsal-(R,R)-2,4-ptn}: N,N′-di-Xsalicylidene-(R,R)-2,4-pentanediamine; X=5-MeO (methoxy), 5-Br, and 5-NO₂) were prepared. The structures and redox potentials for the V(V)/V(IV) couple of the complexes were compared with those of other [VO{Xsal-(R,R)-2,4-ptn}] (X=3-EtO (ethoxy), 3-MeO, and H). The 5-MeO substituted complex which has electron donating groups at the 5-position of the salicylaldehyde moieties forms a monomeric structure in the solid state. The 3-EtO substituted complex has both monomeric and polymeric structures. On the other hand, the other [VO{Xsal-(R,R)-2,4-ptn}] (X=H, 3-MeO, 5-Br, 5-NO₂) complexes have only polymeric structures. X-ray crystal structure analysis of [VO{5-MeOsal-(R,R)-2,4-ptn}]⋅CH₃OH (1) was carried out. Complex 1 has a monomeric five-coordinate square–pyramidal structure. The six-membered N–N chelate ring forms a distorted flattened boat form with two methyl groups in the axial positions.     

Transition Metal-Catalyzed C−H Activation/Annulation Approaches to Isoindolo[2,1-b]isoquinolin-5(7H)-ones

The isoindolo[2,1-b]isoquinolin-5(7H)-one scaffold is widely present in lots of bioactive natural products. Diverse types of strategies have been developed to construct this scaffold. Recently, transition metal-catalyzed C−H activation/annulation is emerging as a powerful and straightforward method to construct diverse polyheterocycles with high atom- and step-economy. It also has been employed for the synthesis of the isoindolo[2,1-b]isoquinolin-5(7H)-one scaffold. This review provides an introduction to recent advances for the preparation of isoindolo[2,1-b]isoquinolin-5(7H)-ones by using transition metal-catalyzed C−H activation/annulation. It will help researchers to find hidden opportunities and accelerate the discovery of novel transformations based on C−H activation/annulation.     

Syntheses,Crystal Structures,and Electro-chemical Properties of Three Anhydrides Based on Ferrocenecarboxylic Acid and Dehydroabietic Acid

Three title compounds(3~5) have been successfully synthesized via interactive reactions between ferrocenecarboxylic and dehydroabietic acids, which can be characterized by FT-IR, elemental analysis, ESI-MS, and NMR spectroscopy. The crystal structures of compounds 4 and 5 can be determined by single-crystal X-ray diffraction. Compound 4 is of orthorhombic system, space group P212121 with a = 7.7010(5), b = 11.7542(9), c = 28.3173(18) ?, Z = 4, V = 2563.3(3) ?~3, Mr = 512.45, Dc = 1.328 g/cm^-1, S = 1.041, μ = 0.619 mm^-1, F(000) = 1088, the final R = 0.0396 and wR = 0.0945 for 4394 observed reflections(I > 2σ(I)). Compound 5 crystallizes in orthorhombic system, space group P21212 as well, with parameters of a = 11.9875(15), b = 19.651(2), c = 7.2163(9) ?, Z = 2, V = 1699.9(3) ?~3, Mr = 582.83, Dc = 1.139 g/cm^-1, S = 1.091, μ = 0.070 mm^-1, F(000) = 636, the final R = 0.0653 and wR = 0.0719 for 1518 observed reflections(I > 2σ(I)). Additionally, electrochemical properties of compounds 3 and 4 have been investigated by the cyclic and differential pulse voltammogram techniques.     

蒎烯吡啶基吡嗪双核镝(Ⅲ)配合物的合成、晶体结构及磁性

采用蒎烯吡啶基吡嗪手性配体(PY)与Dy(TTA)_3反应制备了一个新的双核Dy(Ⅲ)配合物[Dy_2(PY)(TTA)_3](1)。通过X射线单晶衍射确定了配合物的单晶结构,结果表明在晶体生长过程中一个蒎烯基团发生了手性翻转,导致双核镝配合物呈中心对称构型。对配合物进行变温磁化率测试表明,双核镝配合物在无外加直流磁场下即表现出明显的慢磁弛豫性质。     

生物质衍生物γ-戊内酯催化转化制芳烃和2-环戊烯酮的研究

应用浸渍法在ZSM-5沸石分子筛孔道中引入过渡金属Zn物种,制备了具有不同Zn含量的Zn/ZSM-5。考察了反应温度、催化剂用量、催化剂的酸性性质等条件对γ-戊内酯芳构化产物组成(气、液、固产物)及其液体成分含量的影响。实验结果表明,ZSM-5分子筛孔道中引入Zn后,可以有效改变液体产物成分以及影响气体和固体产物收率。当ZSM-5分子筛孔道中引入Zn物种后,能够明显提高液体产物中苯、甲苯、乙苯、萘等芳香类化合物的含量,表明Zn物种能促进γ-戊内酯芳构化反应的进行。     

Design and Applications of Protein‐Cage‐Based Nanomaterials

Materials science is beginning to focus on biotemplation, and in support of that trend, it is realized that protein cages—proteins that assemble from multiple monomers into architectures with hollow interiors—can instill a number of unique advantages to nanomaterials. In addition, the structural and functional plasticity of many protein‐cage systems permits their engineering for specific applications. In this review, the most commonly used viral and non‐viral protein cages, which exhibit a wide diversity of size, functionality, and chemical and thermal stabilities, are described. Moreover, how they have been exploited for nanomaterial and nanotechnology applications is summarized.     

First total synthesis of (+)-hyacinthacine A2

The first synthesis of (+)-hyacinthacine A₂ has been achieved in six steps from 2,3,5-tri-O-benzyl-d-arabinofuranose in an overall yield of 11%. The structure of this natural product was thus unambiguously established as (1R,2R,3R,7aR)-1,2-dihydroxy-3-hydroxymethylpyrrolizidine.     

拉伸诱导的自修复铂配合物薄膜的发光变化

通过接枝含醛基的铂配合物Pt(N^C^N)Cl(N^C^N=1,3-二吡啶基苯)到聚二甲基硅氧烷(PDMS)骨架上,制备了一种弹性橙红色薄膜(PDMS-PtL1)。PDMS-PtL1薄膜具有很好的拉伸性(高达1500%的应变),并表现出较好的室温自修复性能。此外,PDMSPt L1薄膜表现出有趣的拉伸诱导的发光变化,拉伸后可以检测到单分子态铂配合物的~3π-π*发射。该弹性薄膜有效避免了铂配合物发光淬灭的现象,并且实现了外力诱导的发射态转换。     

Catalytic conversion of cellulose into polyols using carbon-nanotube-supported monometallic Pd and bimetallic Pd–Fe catalysts

A series of carbon nanotube (CNT)-supported monometallic Pd and bimetallic Pd–Fe catalysts were synthesized and employed for catalytic hydrogenolysis of cellulose into polyols, including hexitol, ethylene glycol (EG), 1,2-propanediol (1,2-PG), and glycerol (Gly). The physicochemical properties of the catalysts were characterized by nitrogen physical adsorption measurements, X-ray diffraction analysis, transmission electron microscopy, and X-ray photoelectron spectroscopy. The total yield of hexitol, EG, 1,2-PG, and Gly in hydrolytic hydrogenation of cellulose was 37, 55, and 53% for Pd/CNTs, Pd–Fe/CNTs (Pd:Fe = 1:1), and Pd–Fe/CNTs (Pd:Fe = 1:2), respectively. Addition of Fe to Pd significantly modified the physicochemical properties of the nanoparticles and their catalytic performance, especially regarding hexitol selectivity. The promoting effect of Fe, especially for hexitol selectivity, compared with the monometallic catalyst is due to the fact that incorporation of Fe may stabilize Pd⁰ nanoparticles and lead to downshift of the d-band center of Pd metal nanoparticles by charge transfer from Fe to Pd. Recycling experimental results showed that leaching of Fe resulted in a significant decrease in the hexitol yield obtained using the Pd–Fe/CNTs after the first recycle, further demonstrating that Fe element plays a promoting role for hexitol formation.     

基于金属配合物的下转换材料及其光伏应用研究进展

太阳能光伏作为一种把太阳光转换成电能的绿色可再生能源倍受青睐。通过下转换材料将太阳光谱中的紫外光转换为可见光后被太阳能电池更高效地利用,是提高电池光电转换效率的一条可行性途径,引起了科学界的广泛关注。本文将综述用于太阳能电池的下转换材料研究成果,重点介绍基于发光金属配合物的下转换材料及其光伏应用研究进展;同时展望基于太阳能电池用下转换材料开发的发展机遇,以及亟需解决的问题和途径。