{110}晶面取向Ag3PO4多面体的水热制备及可见光催化活性

采用简易水热法在聚乙二醇-6000 (PEG-6000)辅助下合成了Ag₃PO₄多面体.系统考察了水热反应温度、时间及PEG-6000用量对产物形貌和结构的影响.通过X射线衍射(XRD),扫描电子显微镜(SEM),紫外-可见漫反射光谱(UV-Vis DRS)和荧光(PL)光谱等测试手段对光催化剂进行了表征.结果表明,适宜的水热温度及PEG-6000用量是制备具有{110}活性晶面取向Ag₃PO₄多面体的必要条件,该多面体通过纳米颗粒的Ostwald熟化效应生长而成.可见光催化降解罗丹明B (RhB)的实验表明,该Ag₃PO₄多面体活性明显优于其它水热条件下所制备的非{110}取向晶面样品和离子交换法所得纳米颗粒,其降解反应速率常数(k)为离子交换法所得Ag₃PO₄纳米颗粒的8.3倍.总有机碳含量(TOC)及循环实验证明,该Ag₃PO₄多面体可以有效地矿化RhB并保持较好的循环稳定性.活性自由基捕获实验表明,空穴(h⁺)和羟基自由基(·OH)是光催化氧化的主要活性物种.结合活性物种的氧化还原电位以及Ag₃PO₄的能带结构分析,提出了催化反应界面光生电子-空穴(e^--h⁺)对的分离及转移机制.     

Syntheses and Crystal Structures of Two Cadmium(Ⅱ) Compounds Linked by N,N-Bis(3-pyridylmethyl)amine

Two cadmium(Ⅱ) compounds linked by a flexible dipyridyl ligand {[Cd2(Hbpma) Cl5(H2O)]·2H2O}n 1 and [Cd(Hbpma)Cl(H2O)2]2·2SO4·3H2O 2 (bpma = N,N-bis(3-pyridylmethyl)amine) have been synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 crystallizes in triclinic, space group P with a = 9.5612(6), b = 11.3401(7), c = 11.5069(12), α = 112.8540(10), β = 106.5330(10), γ = 101.6680(10)°, V = 1030.77(14)3, C12H20Cd2Cl5N3O3, Mr = 656.36, Z = 2, Dc = 2.115 g/cm3, μ(MoKα) = 2.727 mm-1, F(000) = 636, S = 1.059, the final R = 0.0319 and wR = 0.0822 for 3443 observed reflections (I > 2σ(I)). For complex 2, it belongs to triclinic, space group P with a = 10.9487(4), b = 11.4197(4), c = 15.4288(5), α = 94.7470(10), β = 104.1000(10), γ = 104.42°, V = 1790.76(11)3, C24H42Cd2Cl2N6O15S2, Mr = 1014.46, Z = 2, Dc = 1.881 g/cm3, μ(MoKα) = 1.529 mm-1, F(000) = 1020, S = 1.050, the final R = 0.0178 and wR = 0.0451 for 6026 observed reflections (I > 2σ(I)). Complex 1 is found to have tetranuclear Cd(Ⅱ) clusters which are bridged by the protonated bpma ligands leading to one-dimensional coordination polymers, whereas complex 2 consists of binuclear Cd(Ⅱ) structures linked by the protonated bpma ligands. Both complexes are assembled into three-dimensional supramolecular structures through hydrogen bonding interactions.     

时间分数阶对流-扩散方程的局部间断Galerkin谱方法

提出了求解时间分数阶对流-扩散方程的局部间断Galerkin谱方法.在空间方向上,按局部间断Galerkin谱方法进行离散,时间方向上,对α阶Caputo时间分数阶导数按有限差分格式进行离散,非线性项和源项采用Chebyshev-Gauss-Lobatto插值,从而得到有限差分/局部间断Galerkin谱全离散格式,并且给出了其全离散格式线性情形下的稳定性和收敛性分析.最后给出了一些数值算例,比较了单区域方法和局部间断Galerkin谱方法的数值结果,得出后种方法更具优势.还通过对比Gorenflo-Mainardi-Moretti-Paradisi(GMMP)和有限差分这两种全离散格式下的数值结果,得出有限差分格式在某些问题中比GMMP格式精度更高,收敛速度更快.     

Synthesis,Crystal Structure and Magnetic Property of a New Cd（Ⅱ） Complex with Four Nitronyl Nitroxide Radicals

A new Cd(Ⅱ) complex with four nitronyl nitroxide radicals [Cd(NIT4Py)4Cl2](NIT4Py = 2-(4'-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been synthesized and structurally characterized by X-ray diffraction analysis.It crystallizes in triclinic,space group P1 with a = 7.2441(4),b = 13.6964(8),c = 13.7354(8) ,α = 89.8610(10),β = 77.9180(10),γ = 87.2250(10)°,V = 1331.01(13) 3,C48H64CdCl2N12O8,Mr = 1120.41,Z = 1,Dc = 1.398 g/cm3,μ(MoKα) = 0.573 mm-1,F(000) = 582,S = 1.043,the final R = 0.0257 and wR = 0.0641 for 4333 observed reflections(I > 2σ(I)).The title complex exists in the mononuclear-metal structures,in which each Cd(Ⅱ) ion adopts a distorted octahedral geometry and is coordinated by two Cl-anions and four pyridyl-N atoms from four NIT4Py ligands.The magnetic measurements show weak antiferromagnetic interactions between the nitroxide radicals.     

两个以大环草酰胺为主配体的多核铜及镍配合物的合成及晶体结构

本文利用大环草酰胺与2,2′-联吡啶、间苯二甲酸共配设计并合成了2个同多核配合物[Cu₂L(2,2′-bipy)(H₂O)(ClO₄)]ClO₄ (1)和[Ni₃L₂(ipt)(H₂O)]H₂O (2)(ipt=isophthalic acid,H₂L=2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-diene),并利用单晶X-射线结构分析、红外对该配合物进行了结构表征,研究了其荧光性质。结构分析表明,配合物1为单斜晶系,空间群为P2₁/n,a=1.413 1(17) nm,b=1.091 7(13) nm,c=2.325 4(19) nm,β=119.35(5)°,Z=4。配合物2为单斜晶系,空间群为P2₁/c,a=1.159 7(2) nm,b=2.059 9(4) nm,c=1.847 7(4) nm,β=90.788(3)°,Z=4。配合物1和2分别是通过草酰胺桥联的双核、三核配合物,并通过氢键分别构成三维、二维超分子结构。