对苯二甲醛双缩硫代氨基脲的合成与晶体结构

对苯二甲醛双缩硫代氨基脲的合成与晶体结构;杀菌活性     

含Eu(Ⅲ)和Gd(Ⅲ)共轭高分子配合物发光性质研究

线性共轭高分子P-1是由单体1,4-二溴-2,3-二正丁氧基萘(M-2)和5,5′-二乙烯-2,2′-联吡啶(M-3)通过Pd催化Heck偶合反应合成得到,高分子配合物P-2和P-3由高分子P-1和Eu(TTA)₃·2H₂O和Gd(TTA)₃·2H₂O反应生成。高分子P-1能发射强蓝绿色荧光。高分子配合物P-2和P-3发光性能测试表明,含有Eu(Ⅲ)的高分子配合物P-2不仅显示高分子荧光,而且还显示了Eu(Ⅲ)(⁵D₀ → ⁷F₂)特征荧光,含Gd(Ⅲ)的高分子配合物P-3仅发射高分子的荧光,其荧光波长相对P-1而言,呈现13 nm红移。     

Self-assembly of a mesoporous ZnS/mediating interface/CdS heterostructure with enhanced visible-light hydrogen-production activity and excellent stability

We designed and successfully fabricated a ZnS/CdS 3D mesoporous heterostructure with a mediating Zn_1–xCd_xS interface that serves as a charge carrier transport channel for the first time. The H₂-production rate and the stability of the heterostructure involving two sulfides were dramatically and simultaneously improved by the careful modification of the interface state via a simple post-annealing method. The sample prepared with the optimal parameters exhibited an excellent H₂-production rate of 106.5 mmol h^–1 g^–1 under visible light, which was 152 and 966 times higher than CdS prepared using ethylenediamine and deionized water as the solvent, respectively. This excellent H₂-production rate corresponded to the highest value among the CdS-based photocatalysts. Moreover, this heterostructure showed excellent photocatalytic stability over 60 h.     

Self-assembly of zinc polymers based on a flexible linear ligand at different pH values: Syntheses,structures and fluorescent properties

Five novel coordination polymers, [Zn(imbz)₂]_n (1), {[Zn(imbz)₂]·H₂O}_n (2), [Zn(imbz)(μ₂-OH)]_n (3), [Zn₃(imbt)₂(p-bdc)₃]_n (4), [Zn₄(μ₃-OH)₂(imbt)₂(p-bdc)₃]_n (5), (imbt = 4′-(imidazol-1-ylmethyl)benzonitrile, imbz^? = 4′-(imidazol-1-ylmethyl)benzoate and p-bdc = terephthalic acid) have been hydrothermally prepared through systematically changing the pH values of reaction mixture, and structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray crystallography. Compounds 1 and 2 exhibit similar 2D (4,4) grid structures, whereas compound 2 contains a right-handed helix along b-axis. Compound 3 has a distorted diamond framework which was constructed via imbz^? ligands and μ₂-OH groups linking metal atoms. Compound 4 shows a 2D 6-connected network with trinuclear zinc clusters as secondary building units (SBUs), whereas 5 shows a distorted α-Po with tetranuclear zinc clusters as SBUs, in which p-bdc ligands act as bridges. Moreover, compounds 1–5 all exhibit strong blue photoluminescence in the solid state at room temperature.     

Syntheses and characterizations of five coordination polymers constructed by 3,5-bis(pyridin-3-ylmethoxy)benzoic acid ligand

Five coordination polymers, namely [Cd(L3)₂]·H₂O (1), [Zn(L3)₂] (2), [Co(L3)₂] (3), [Ni(L3)₂] (4) and [Cu₂(L3)₂]·3H₂O (5), where L3 = 3,5-bis(pyridin-3-ylmethoxy)benzoic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. Compound 1 is a binodal (3,4)-connected net with (6³)(6⁶) topology. Compounds 2–4 are isostructural and described by the uninodal (4,4)-connected net with (4⁴ · 6²) Schläfli symbol. The structure of 5 is a 2D binodal (6,3) net. In addition, the luminescent properties of compounds 1 and 2 have been studied in the solid state at room temperature.     

An unprecedented (6,8)-connected self-penetrating network based on two distinct zinc clusters

The first (6,8)-connected self-penetrating metal-organic framework has been constructed using an asymmetric neutral ligand based on dinuclear zinc clusters, as six-connected nodes, and trinuclear zinc clusters as eight-connected nodes, representing the highest-connected binodal network topology presently known for self-penetrating systems.     

淀粉系高吸水性树脂反应中间体稳定性及反应活性的量子化学研究

运用abinitioUHF方法和DFTUB3LYP方法在6-31G基组水平下对淀粉系高吸水性树脂反应中间体的模型体系进行几何构型优化.针对每类自由基对应得到的两种典型的构象异构体(1_a,1_b和2_a,2_b),进行稳定性和反应活性分析.构型1_a和2_b的总能量相对较低.比较4个模型体系的前线分子轨道,构型1_a的能隙较小,同时HOMO能量较高,易给出电子,LUMO能量较低,易得电子,有利于电子转移,因而有较好的反应活性.自由基自旋密度主要集聚在C2或C3上,未有较大弥散,同时也是前线MO主要布居位置和重要的反应活性部位.对构型1_a与丙烯酸模型分子形成的复合物分析表明,两者的反应未经过过渡态,在瞬间即可完成.     

Local Transient Jamming in Stress Relaxation of Bulk Amorphous Polymers

Bulk amorphous polymers become stretched and parallel-aligned under loading stress, and their intermolecular cooperation slows down the subsequent stress relaxation process. By means of dynamic Monte Carlo simulations, we employed the linear viscoelastic Maxwell model for stress relaxation of single polymers and investigated their intermolecular cooperation in the stress relaxation process of stretched and parallel-aligned bulk amorphous polymers. We carried out thermal fluctuation analysis on t...     

基于酰腙类Schiff碱的锌和镉配合物的合成、晶体结构和性质

采用溶剂挥发法合成了配合物[M（HBrsth）₂]（M=Zn（1）,Cd（2）,H₂Brsth=5-溴水杨醛缩噻吩-2-甲酰腙）和配合物[Cd（L）₂]（3,HL=2-乙酰基吡啶缩异烟酰腙）,并经元素分析、红外光谱、紫外光谱和热重分析等对它们进行了表征。用X射线单晶衍射分析确定了配合物1和3的晶体结构,1属单斜晶系,C2/c空间群,呈现一维链状配位聚合结构;3属正交晶系,C2cb空间群。用MTT法测试了配合物对人肝肿瘤细胞HEPG2和人结肠癌细胞SW620的增殖抑制作用。还研究了配合物的发光性质。     

Covalent Organic Framework Materials for Photo/ Electrocatalytic Carbon Dioxide Reduction北大核心CSCD

Covalent organic frameworks （COFs）are a class of emerging materials connected by covalent bonds,which have high thermal/chemical stability （except boric acid COFs）,permanent porosity,large specific surface area and good crystallinity. In addition,the structure of the monomer unit in COFs is adjustable and can coordinate with many transition metal ions to provide catalytic active sites. These advantages make COFs helpful to catalyze various reactions. Among them,COFs have an excellent catalytic effect on the CO2 reduction reaction（CO2 RR）. This is mainly because the adjustable pore structure of COFs allows them to adsorb a large amount of CO2 and the π-π stacking structure in COFs can promote charge transfer, which can greatly improve the efficiency of CO2 reduction. COFs can be used as photo/ electrocatalysts to efficiently reduce CO2 to CO,CH4 ,HCOOH and other products. This review discusses the important achievements of CO2 RR catalyzed by COFs, including photo/electrocatalytic CO2 RR and photoelectric coupling CO2 RR. In addition,the future development of COFs as CO2 RR catalysts is also prospected. © 2022, Science Press (China). All rights reserved.