Dioxygen affinities and catalytic oxidation performance of cobalt(Ⅱ) hydroxamates with benzo-15-crown-5 pendants

The oxygenation constants （Ko2） of cobalt（Ⅱ） hydroxamates （CoL^1 2-CoL^3 2） with benzo-15-crown-5 （B15C5） pendants were measured over the range of -5 to ＋20 ℃, and the values of thermodynamic parameters （ΔH^0 and ΔS^0） were calculated based on these （Ko2） values, Meanwhile, these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110Δ under normal atmospheric pressure. The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O2-binding capabilities and oxidation for p-xylene were investigated with the comparison of crown-free analogues CoL^4 2.

Microcalorimetric study on host-guest complexation of naphtho-15-crown-5 with four ions of alkaline earth metal

Thermodynamic parameters of complexation of naphto- 15-crown-5 with four alkaline earth ions in aqueous media was determined using titration microcalorimetry at 298.15 K. The stability of the complexes, thermal effect and entropy effect of the complexation is discussed on the basis of the guest ions structure and the solvent effect. The stability constants tendency to vary with ion radius was interpreted. Complex of naphtha-15-crown-5 with calcium ion is very stable due to the synergism of static electric interaction and size selectivity between the host and the guest.

The Novel Benzo-15-Crown-5 with Palladium(II) Complex: [Na(B15CS)]_2,[Pd(SCN)_4]

A novel Pd(II) Benzo-15-crown-5 complex [Na(B15CS)]_2[Pd(SCN)_4] has been isolated and characterized by IR and X-ray diffraction analysis. The crystal structure belongs to monoclinic, space group P2_1,/n with cell dimensions, a = l.0164(6), b = l.3743(3), c = l.4987(7) nm, β = 95.248(6) °, V = 2.0847 'nm_3, Z = 2, F(000) = 944, R = 0.053, Rw = 0.072. The compound consists of two [Na(B15CS)]+ complex canons and a [Pd(SCN)4_]^(2-) complex anion. Each sodium ion is coordinated by five crown ether oxygen atoms and one N atom from the SCN group of [Pd(SCN)_4]^(2-) to form stable neutral complex.

STUDISS ON HETERO-MACROCYULIC POLYETHER(Ⅲ).THE SYNTHESES OF 10-TELLURABENZO-15-CROWN-5 AND ITS PLATINUM COMPLEX AS WELL AS ITS CATALYTIC BEHAVIOR IN HYDROSILYLATION

The syntheses of a new type of heteromacrocyclic polyether- 2,3-benzo-1,4,7,13-tetraoxa-10-telluracyclopentadeca-2-ene(L),and its pla- tinum complex(PtL_2Cl_2)were described.The catalytic activity of this complex for the hydrosilylation of olefins by triethoxysilane was investigated.

STUDIES ON COMPLEXES OF RARE EARTHS WITH CROWN ETHERS(Ⅳ)SYNTHESIS AND CHARACTERIZATION OF THE COMPLEXES OF RARE EARTH NITRATES WITH 4'-BROMO-5'-NITROBENZO-15-CROWN-5

Six new solid complexes of macrocyclic polyether ligand 4′-bromo-5′-nitrobenzo-15-crown-5(L)with Uivalent rare earth nitrates having composition of RE(NO_3)_3·L·mCH_3CN·nH_2O(RE=L_a--Nd,m=n=0, RE=Sm,Bu,m=0.1,n=1,4)have been synthesized in acetonitrile or acetone.All the isolated complexes have been char- acterized by elementary analysis,IR and UV spectra,differential thermal and thermogravimetric analysis,X-ray powder diffraction analysis,molar conductance and measurementa of solubility in some general solventa.It shows that coordination number of the rare earth cation in the complexes of La,Ce,Pr and Nd nitrate is eleven.

STUDIES ON HETERO-MACROCYCLIC POLYETHER (Ⅱ). THE SYNTHESIS OF PLATINUM COMPLEX OF 10-SELENABENZO-15-CROWN-5 AND ITS CATALYTIC BEHAVIOR IN HYDROSILYLATION

The title complex (PtL_2Cl_2) was synthesized by reacting 10-selenabenzo-15-crown-5 (L) with potassium chloroplatinite. Its catalytic activity for the hydrosilylation of olefins by triethoxysilane, was investi gated.

STUDIES ON HETERO-MACROCYCLIC POLYETHER(1).THE SYNTHESIS OF 10-SELENA BENZO-15-CROWN-5

The synthesis of a new type of hetero-macrocyclic polyether 2,3-henzo-1,4,7,13-tetraoxa-10-selenacyclopentadeca-2-ene is deseribed.

Synthesis and Crystal Structure of 〔Na(N-(p-chlorophenyl)aza-15-crown-5)-(Et_2O)〕_2 (Na_2W_(0.5)Mo_(7.5)O_(26))

[Na (N- (p-chlorophenyl ) aza-15--crown--5 ) (Et2O )]2 (Na2W0.5 Mo7.5 O26), Mr= 2119. 4, monoclinic, space group P21/c, a= 17. 803(4), b= 13. 674 (3), c= 14. 610(3), β= 112. 33(3)°, V=3290(1) A3, Z= 2, Dc= 2. 139 g/cm3, μ= 1.704 mm-1, F (000) = 2079, R = 0. 026, Rw= 0. 030. The supermolecular complexconsists of one [Na2W0.5Mo7.5O28)2- anion in which only two Mo atoms are replaced byW in 25% (M= l/4W+3/4Mo) and the two Na+ are linked symmetrically to neighbouring [W0.5Mo7.5O26]4- units on the right and the left respectively and two complexcanons in which each Na+ deviates from the plane of the four ether oxygens and is coordinated to every hetero--atom in the crownether ring, and is also coordinated to the Oatom of Et2O.

CRYSTAL AND MOLECULAR STRUCTURE OF { CNa(15-crown-5)]_n [Cd(SCN)_3]}_n

The complex [Na(15-crown-5)] [Cd(SCN)3] (15-crown-5 = C10H20 O5) crysializes in monoclinic space group P21/c with a=10. 219(2) ,b= 10. 575(2) ,c= 20. 572(2) A ,β=98. 45(1)°,V= 2198. 7A3,Mr=529. 89,Z = 4,Dx=1. 600g/cm3,F (000) -1052,μ= 15. 708cm-1. The structure was solved by direct methods with the final R=0. 064. Results of structure analysis indicate that the Na ion is bonded by 15-crown-5 to form a complex cation and the Cd(Ⅱ) is bonded by six SCN ion to form an anion chain with a distorted octahedral coordination.

CRYSTAL AND MOLECULAR STRUCTURE OF BENZO-15-CROWN-5 POTASSIUM TETRACHLOROAURATE K(C_(14)H_(20)O_5)_2-AuCl_4

The crystal and molecular structure of the title compound K(C14 H20O5)2AuCl4 has been determined by X-ray diffraction method.The crystallographic data are as follows;Mr=914.51,triclinic,space group P1,a=10.988(2),b=13.472(4),c=13.696(2)A,α=77.72(1),β=79.02(2),γ=64.92(2)°,V=1782.6(4)A3,Z=2,Dc=1.704 g.cm-3,μ=45.858 cm-1,F(000)=454,R=0.019,Rw=0.018 for 5697 observed reflections with I≥3σ(I).X-ray structure determination shows that benzo-15-crown-5(B15C5)forms a 2:1 complex with KAu-C14 in which K+is sandwiched between two crown rings.The dihedral angle between these two ether oxygen planes is 11.9°.The anion AuCl4-has a planar square configuration which is bound with the complex cation K(B15C5)2+by electrostatic force to form an ion-pair.

Synthesis and Crystal Structure of 13-Phenyl-1,10-dithia-4,7-dioxa-13-aza-15-Crown-5

Crystal structure of the title compound C 16 H 25 O 2NS 2 has been determined by X-ray diffraction method. Its crystallographic data were as follows: M r=327.51, triclinic, space group P1, a=8.864(3), b=10.127(4), c=10.390(3) , α=105.94(3), β=103.10(2), γ=90.96(3)°, V=870.3(7) 3, Z=2, D c=1.250g.cm -3 , μ(MoKα)=2.966cm -1 , F(000)=176, a total of 3275 reflections measured (2θ max =50°), 2246[I5σ(I)] used in the refinement, R=0.067, R w=0.082. The result shows that the distances of N(1)-C(2) and N(1)-C(3) are longer than that of N(1)-C(11), which indicates that the interaction of C Ar -N sp 2 is stronger than that of C sp 3 -N sp 2 . Oxygen, nitrogen and sulfur atoms of the ring in the same plane was deduced from the least\|squares planes and the dihedral angles.

β-淀粉样蛋白调控miR-15a激活Bag5在阿尔茨海默病神经细胞凋亡中的作用

目的:阿尔茨海默病(Alzheimer’s disease,AD)的患病率在全球范围内不断增加,然而其发病机制尚不清楚。研究表明AD的进展与神经细胞凋亡密切相关。本研究旨在探讨miR-15a和Bag5在β-淀粉样蛋白(β-amyloid protein,Aβ)诱导的AD神经细胞凋亡中的作用及其具体机制。方法:通过给SD大鼠脑部注射Aβ42构建AD大鼠模型,并使用Aβ42处理SH-SY5Y细胞构建AD细胞模型。采用莫里斯(Morris)水迷宫实验检测大鼠的学习记忆能力;苏木精-伊红(hematoxylin and eosin,HE)染色检测大鼠脑组织的病理变化;尼氏(Nissl)染色检测脑组织中细胞形态以及数量变化;生物信息学分析筛选与Bag5相互作用的上游miRNA;四甲基偶氮唑盐(methyl thiazolyl tetrazolium,MTT)检测细胞增殖能力;流式细胞术检测细胞的凋亡率;实时反转录聚合酶链反应(real-time reverse transcription PCR,real-time RT-PCR)检测miR-15a和Bag5的mRNA水平;蛋白质印迹法检测Bag5、Bax和Caspase-3的蛋白质表达水平。分别采用miR-15a敲减或过表达载体以及Bag5敲减载体处理大鼠和细胞,萤光素酶报告实验验证miR-15a与Bag5之间的结合关系。结果:Morris水迷宫实验、HE染色和Nissl染色结果表明AD大鼠模型成功建立,且Aβ可诱导AD大鼠中神经细胞凋亡和抑制miR-15a表达。与正常细胞相比,Aβ处理可显著增加细胞凋亡率和Bag5的表达,降低细胞活力和miR-15a表达,过表达miR-15a会进一步加强Aβ对细胞增殖和凋亡的效果,而敲减miR-15a的表达则起到相反的作用(均P<0.01)。萤光素酶报告实验证明miR-15a与Bag5存在负向靶向关系。且与单独敲减Bag5相比,敲减miR-15a和Bag5共转染会显著提高细胞活力以及Bag5的表达,同时明显降低细胞的凋亡率以及Bax、Caspase-3的表达,体内实验也得到一致的结果(均P<0.01)。结论:Aβ可抑制miR-15a的表达,进而诱导Bag5表达,以激活Bag5对于Aβ引起凋亡的保护作用。

LncRNA MEG8通过靶向miR-15a-5p调控MICA/B介导结直肠癌细胞免疫逃逸

目的:探究长链非编码RNA母系表达基因8(LncRNA MEG8)通过靶向miR-15a-5p调控MHCⅠ类相关蛋白A/B(MICA/B)介导的结直肠癌(CRC)细胞免疫逃逸机制。方法:RT-qPCR、Western blot检测CRC组织和细胞系MEG8、miR-15a-5p、MICA、MICB、NKG2D蛋白水平;双荧光素酶实验验证MEG8对miR-15a-5p的调控关系;采用脂质体转染法将NC、MEG8、miR-NC、miR-15a-5p分别或共转染至SW480、SW620细胞,记为NC组、MEG8组、MEG8+miR-NC组、MEG8+miR-15a-5p组;将NK细胞分别与SW480、SW620细胞共培养;ELISA检测共培养液中TNF-α、IFN-γ水平;CCK-8、EdU染色、Transwell实验检测细胞增殖、迁移和侵袭能力;RT-qPCR、Western blot检测细胞MEG8、miR-15a-5p、MICA、MICB、NKG2D蛋白水平。结果:与癌旁组织或正常结肠上皮细胞相比,CRC组织和细胞系中MEG8、MICA、MICB、NKG2D mRNA和蛋白水平降低,miR-15a-5p水平升高(P<0.05)。MEG8靶向调控miR-15a-5p。共培养体系中,与NC组相比,MEG8组细胞MICA、MICB、NKG2D蛋白水平、共培养上清液中TNF-α、IFN-γ水平明显升高,培养1 d、2 d、3 d后,OD值、EdU阳性率、迁移和侵袭细胞数明显降低(P<0.05);过表达miR-15a-5p能部分逆转过表达MEG8对细胞MICA、MICB、NKG2D、TNF-α、IFN-γ水平和增殖、侵袭转移能力的影响(P<0.05)。结论:MEG8通过靶向miR-15a-5p调控MICA、MICB表达,促进NK细胞活性,抑制CRC细胞免疫逃逸。

Construction of a PVC based 15-crown-5 electrochemical sensor for Ag(Ⅰ) cation

The macrocyclic ligand,15-crown-5,was used as an ionophore for fabrication of a polyvinyl chloride（PVC） based membrane sensor for Ag（Ⅰ） cation.For construction of the Ag（Ⅰ） cation selective electrode the best response characteristics were obtained using the composition： 15-crown-5/PVC/o-nitrophenyloctylether（NPOE）/sodium tetraphenyl borate（NaTPB） in the percentage ratio of 5.6/30/60.5/3.9（w/w/w/w）.The electrochemical sensor shows a linear dynamic range 1.0 10 7–1.0 10 1mol/L and a Nernstian slope of 58.9 0.5 mV/decade with a detection limit of 8.09 10 8mol/L for Ag（Ⅰ） cation.It has a fast response time of 〈10 s and can be used for at least 8 weeks without any considerable divergences in its potential response.It was successfully used as an indicator electrode in potentiometric titration of Ag（Ⅰ）cation with I and Cl anions and also for the determination of this metal cation in radiology waste water.

航空用17-4PH表面激光熔覆15-5PH涂层组织与性能分析

17-4PH不锈钢广泛应用于航空航天领域涡轮机叶片等关键零部件。为实现航空用17-4PH零部件损伤后的修复与再制造,利用激光熔覆技术在17-4PH表面制备15-5PH涂层,并对涂层的物相、显微组织、显微硬度、耐磨性能及耐腐蚀性能进行分析。结果表明,涂层主要由Fe-Cr、马氏体及α-Fe组成;涂层与基体的结合区为平面晶,底部及中部以柱状晶为主,顶部由柱状晶和少量等轴晶组成。涂层与基材的平均显微硬度分别为408.7HV_(0.5)和347.5HV_(0.5),涂层硬度较基材提高17.6%;涂层与基材的平均摩擦系数分别为0.3051和0.3754,磨损截面面积分别为813.74μm^(2)和2058.12μm^(2),涂层的耐磨损性能明显优于基材。涂层与基材的自腐蚀电位(E_(corr))分别为-1.0780 V和-1.0975 V,自腐蚀电流密度(I_(corr))分别1.229×10^(-3) mA/cm^(2)和0.907×10^(-3) mA/cm^(2),涂层的耐腐蚀性能与基材相当。涂层的组织及表面性能结果表明,激光熔覆15-5PH涂层可用于航空用17-4PH零部件的修复与再制造。

Synthesis of Unsymmetrical Bissalicylaldimine Ligands and bis-Schiff Base Cobalt Complexes with Benzo-10-aza-15-crown-5 Pendant

Novel unsymmetrical bissalicylaldimine bis-Schiff bases with a benzo-10-aza-15-crown-5 pendant and their cobalt complexes have been synthesized via condensation of 3 or 5-[（benzo-10-aza-15-crown-5）-10-ylmethyl] salicylaldehyde with the half unit Schiff bases and characterized by ^1H NMR, IR, mass spectroscopy, elemental analysis, molar conductances and molar magnetic susceptibility.

Metal Ion Enhanced Phosphorescence of 2,3-Naphtho-10-aza-15-crown-5: A Possible Molecular Photonic Operator

A novel crown ether, 2,3-naphtho-10-aza-15-crown-5 (NAC) was synthesized.This compound does not show strong fluorescence and phosphorescence due to photoinducedintramolecular electron transfer from the nitrogen lone pair of electrons to the singlet excitedstate of the naphthalene chromophore. Complexation with heavy-metal ions results in the quenching ofthe fluorescence and enhancement of the phosphorescence significantly. These observations wereinterpreted in terms of the binding interactions, between the nitrogen lone pair electrons and themetal cation, which prevent photoinduced intramolecular electron transfer, and the heavy-atomeffects which induce quenching of the fluorescence and enhancement of the phosphorescence. Theseazacrown and heavy-metal-based systems could be useful as potential chemical sensors and molecularphotonic devices.

回火温度对15Cr5MoVRE油井管钢组织及第二相析出行为影响

研究了回火温度对15Cr5MoVRE油井管钢组织和第二相析出行为规律的影响。利用箱式热处理炉对试验钢进行了热处理,采用光学显微镜和透射电镜对回火后的组织及第二相进行了观察分析,采用硬度计与拉力试验机对试验钢回火后的力学性能进行了测试。结果表明,15Cr5MoVRE油井管钢,经900℃保温50 min水淬,670~710℃回火保温90 min,组织为回火屈氏体和回火索氏体,析出的第二相碳化物类型均为M_(7)C_(3)型和M_(23)C_(6)型。随着回火温度的升高,第二相碳化物颗粒数量明显增多,尺寸逐渐增大,且在710℃回火时发生团聚。回火温度为690℃时,铁素体基体上有大量细小的第二相碳化物均匀析出,力学性能最优,试验钢的最佳回火温度应为690℃。