Synthesis and Crystal Structure of a New Mononuclear Nickel(Ⅱ) Mixed Complex Derived from 2-Aminoethyl-bi(3-bi-aminopropyl)amine with 1,10-Phenanthroline

The mixed complex [Ni(L)(L')](ClO4)2 has been synthesized using 2-aminoethyl- bi(3-bi-aminopropyl)amine with phen (1,10-phenanthroline) in the presence of Ni(II) ion, and its structure was determined by X-ray diffraction. The crystal crystallizes in monoclinic, space group P21/c with a = 13.713(2), b = 13.1466(19), c = 14.780(2) (A), β = 97.620(3)°, V = 2640.9(7)(A)3, F(000) = 1272, Z = 4, Dc = 1.540 g/cm3, R = 0.0536 and wR = 0.1207. The Ni2+ ion is six- coordinated to furnish a distorted octahedral geometry.     

Theoretical Study on Enol-keto Tautomerism of α-Fluorine-β-diketones

Density Functional Theory method is applied to investigate the enol-keto tautome- rism of both acyclic and cyclic α-fluorine-β-diketones. It is shown that, for acyclic cases, α-fluorine could improve the relative stability of keto tautomer by lessening intramolecular hydrogen bond of enol form, whereas the relative stability of cyclic enol could be attributed to two factors: destabi- lization of keto and stabilization of enol. Furthermore, the relative stabilities of all enol tautomers are improved in THF to different extents.     

Synthesis and Crystal Structure of 4,4′-(4-(1-Naphthyl)-4-phenyl- 1,3-butadienylidene)-bis[N,N-diethylbenzenamine]

The title compound (C40H42N2) has been synthesized by the reaction of 1-(1-naphthyl)-1-phenyl-3-chloropropylene and bis(4-(diethylamino) phenyl)methanone, and characterized by IR, 1H NMR, MS and X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 17.047(3), b = 10.807(2), c = 1&494(4) (A), β = 105.727(4)°, V=3279.4(11) A3, Mr = 550.76, Z = 4, Dc = 1.115 g/cm3, μ(MoKα) = 0.085 mm-1, F(000) = 1184, the final R = 0.0625 and wR = 0.1384 for 2276 observed reflections (I ＞ 2σ(Ⅰ)). X-ray analysis reveals that the butadiene fragment adopts a planar cisiod conformation and makes a dihedral angel of 69.4(2)° with the naphthalene ring.     

Synthesis, Spectroscopic Properties and Crystal Structural Characterization of a Triphenyltin(Ⅳ) Complex with 5-Bromonicotinic Acid

A novel organotin complex [Ph3Sn(C2H5OH)(OCOC5H3NBr)SnPh3(OCOC5H3NBr)]has been synthesized by the reaction of 5-bromonicotinic acid with triphenyltin hydroxide in ethanol and characterized by elemental analysis, IR and 1H NMR. The crystal structure was determined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 15.564(2), b = 24.975(4), c = 12.2973(19) (A), β = 92.224(2)°, Z = 4, V = 4776.5(13) (A)3, Dc = 1.596g/cm3, μ(MoKα) = 2.765 mm-1, F(000) = 2264, R = 0.0385 and wR = 0.0667. In the molecular structure of the title complex, the tin atoms are five-coordinated in a trigonal bipyramidal geometry.     

基于第一性原理的单层WS2热输运特性研究

二维WS₂是一种层状过渡金属硫化物,因其具有特殊的层状结构、可调带隙及稳定的物理化学性质而备受关注。结合玻尔兹曼输运方程(BTE)和密度泛函理论(DFT),利用第一性原理研究了单层WS₂声子的输运特性,分析了声子的谐性效应和非谐性效应对WS₂晶格热导率的影响机理,计算了其声子的临界平均自由程,提出通过调整阻断频率的方法来调控WS₂的晶格热导率。研究结果表明：单层WS₂在300 K时的本征晶格热导率为149.12 W/(m·K),且随温度的升高而降低;从各声子支对总热导率的贡献来看,声学声子支起主要作用,特别是纵向声学(longitudinal acoustic, LA)声子支对单层WS₂热导率的贡献百分比最大(44.28%);单层WS₂声学声子支和光学声子支之间的较大带隙(声光学声子支之间无散射)导致其具有较高的晶格热导率。本文研究可为基于单层WS₂纳米电子器件的设计和改进提供借鉴和理论指导。     

非金属掺杂改性g-C3N4光催化降解水中有机污染物的研究进展

近年来,石墨相氮化碳(g-C₃N₄)以其合适的带隙宽度、丰富的活性位点和成本低廉等优点,成为新兴的可见光响应非金属光催化剂,被广泛应用于光催化降解有机污染物领域。然而,纯g-C₃N₄对可见光的吸收效率较低且光生电子和空穴复合速率快,导致其光催化活性处于较低水平。基于g-C₃N₄的非金属特性,通过非金属掺杂可以有效提高g-C₃N₄的光催化性能,引起了学者们的广泛关注。本文介绍了目前非金属掺杂g-C₃N₄复合材料常见的制备方法,着重归纳了不同类型的非金属掺杂g-C₃N₄光催化降解水中有机污染物的相关研究进展,探讨其作为光催化剂在可见光条件下降解有机污染物的相关机理。最后,提出目前g-C₃N₄基复合材料在光催化降解水中有机污染物中所面临的挑战,旨在为非金属掺杂g-C₃...     

两个基于2,5-二甲氧基对苯二甲酸和咪唑衍生物的超分子钴配位聚合物的结构及光催化反应

本文以咪唑衍生物为配体,通过水热合成法与钴离子制备出两个配位聚合物:{[Co(DTA)(1,4-DIB)(H₂O)]·H₂O}_n(1)和[Co(DTA)(1,3-BMIB)]_n(2)(1,4-DIB=1,4-二(1H-咪唑-1-基)苯; 1,3-BMIB=1,3-二(4-甲基-1H-咪唑-1-基)苯;H₂DTA=2,5-二甲氧基对苯二甲酸)。利用X射线单晶衍射、粉末衍射、热失重、元素分析、红外光谱以及固体紫外-可见光谱等对两个配合物进行了表征。结构分析证实配合物1和2是通过二维结构堆积成的三维超分子化合物。粉末衍射测试则显示两个配合物在水中有很好的稳定性。固体紫外-可见光谱显示两个配合物属半导体材料,对紫外-可见光有很强的吸收作用。在光催化实验中,配合物1和2可加快亚甲基蓝的降解速度。     

高效液相色谱法鉴别黑色签字笔墨水字迹形成时间的研究

签字笔携带方便、书写流畅,现已成为常用的书写工具之一。在许多刑事及民事案件中,尤其在呈明显上升趋势的各类贪污、受贿案件中,经常会遇到由签字笔墨水形成的契约、合同、收据、借条等可疑文件中关于签字笔墨水字迹色痕的鉴定。对于字迹色痕形成时间的鉴定工作一直是困扰法庭     

兔主动脉冻结过程中未冻水份额的研究

利用差示扫描量热仪(DSC)技术中的分步扫描(Stepwise scanning)法,研究了不同浓度的低温保护剂对主动脉血管冻结过程中未冻水份额的影响。研究结果表明:分步扫描量热技术可以用于血管材料冻结过程中未冻水份额的定量研究,而且具有较高楠度;随着低温保护剂二甲亚砜(DMSO)浓度的增大,血管的初始冻结点温度呈线性降低,但其冻结过程的未冻水份额显著增大,这是由于高浓度DMSO具有很强水合能力所致。     

动叶顶部间隙对1+1/2对转涡轮性能的影响

本文对1+1／2对转涡轮中动叶顶部间隙大小对涡轮性能的影响进行了详细的数值模拟。对涡轮总体性能参数、节距平均出口气流角、出口节距平均相对马赫数以及不同叶高的负荷进行了对照,发现间隙对1+1／2对转涡轮性能影响明显,尤其是当间隙较大时。当低压动叶间隙宽度达到高压动叶前缘叶高的4．5％时,低压动叶间隙中流动普遍超音,在设计1+1／2对转涡轮时需要加以重点考虑。