Dy3+在Ba3La(BO3)3 中的光致发光

研究了Ba3La(BO3)3 基质中Dy3 的光致发光特性; 探讨了RE3 的电荷半径比(z/r)和Ce3 , Dy3 含量对Dy3 发光强度及发光颜色的影响; 分析了Ba3La(BO3)3 中Ce3 对Dy3 发光的敏化作用; 确定了Dy3 的 4F9/2→6H15/2及4F9/2→6H13/2跃迁发射的浓度猝灭机制均为电偶极-电四极相互作用.     

钙钛矿CH3NH3PbI3晶体的电化学

电化学方波伏安及循环伏安测量表明,钙钛矿CH₃NH₃PbI₃晶体在有机电解质中的氧化还原过程伴随着化学降解。该化学降解源于CH₃NH₃PbI₃晶体中铅离子的还原以及碘离子的氧化。通过电化学伏安法可以测定晶体的能带。     

LaVO3和NdVO3的合成

以Ｖ２Ｏ３为起始原料，在氩气中合成了ＡＢＯ３型稀土钒化合物，对加热前通氩气的时间，Ｖ２Ｏ３∶Ｌａ２Ｏ３的配比等进行了探讨，得到了适宜的制备条件。首次报道了ＬｎＶＯ３（Ｌｎ＝Ｌａ，Ｎｄ）的热学性质，发现ＬａＶＯ３具有吸附二氧化碳的特性。     

KMgF3:Ce3+,Tb3+纳米粒子中Ce3+→Tb3+的发光及能量传递

利用微乳液方法,合成了铈、铽共掺杂的氟镁钾纳米粒子,研究了体系中Ce3+→Tb3+的发光特性以及它们之间的相互作用,结果表明KMgF3:Ce3+Tb3+纳米粒子中存在Ce3+→Tb3+的能量传递过程,即Ce3+可以将吸收的能量直接传递给Tb3+离子,使得Tb3+的绿色发光强度大为增加.     

[{(C5Me4R)Ru}3Ru(η3-As3)(μ3,η3-As3)(μ3-As)3], arsenreiche Vierkerncluster

The interaction of [(η⁵-C₅Me₄R)Ru(CO)₂]₂ (1a: R = Me, 1b: R = Et) with yellor arsenic, As₄, affords besides the pentaarsaruthenocenes [(η⁵-As₅)Ru(η⁵-C₅Me₄R)] (2a, 2b) the tetranuclear clusters [{(η⁵-C₅Me₄R)Ru}₃Ru(η³-As₃)(μ₃,η³-As₃)(μ₃-As)₃] (3a, 3b). The structure of 2b and 3b has been elucidated by X-ray analysis.     

Non-Isothermal Kinetics of the Decomposition Reaction of Cluster [Ag3WS3Br]（PPh3）3 and [Cu3WS3Br]（PPh3）3

The thermal behaviors of clusters [Ag3WS3Br](PPh3)3 and [Cu3WS3Br](PPh3)3 (PPh3=triphenyl phosphine) in a nitrogen atmosphere were studied under the non-isothermal conditions by simultaneous TG-DTG-DSC and EDS techniques. The results showed that the evolution of PPh3 generally proceeded before the release of the other moiety in one or two step-mode. The mechanisms, the kinetic and the thermodynamic parameters for decomposition of PPh3 of both clusters were determined and calculated by jointly using several methods, which showed that its evolution was controlled by Avrami-Erofeev equation. The results also showed that there was no new stable phase composed of W-Ag(Cu)-S-Br after release of organic moiety PPh3 and that CVD method was not applicable to their further processing.     

有关NdCl_3·3ROH-AlEt_3催化体系的活性

<正> 我们曾指出,在NdCl_3·3ROH-AlEt_3体系中,醇的作用在于它的给电子性将会降低稀土离子的正电性,从而减弱Nd-Cl键的离子性,同时引起晶格的变化,使之有利于烷基化作用的发生,导致活性提高。本实验采用一种简便的方法证实了这种作用的发生。 这个方法所根据的原理是一般Ziegler-Natta型催化组分的熟知反应形式:     

三水硝酸镝与苯并-15-冠-5在丙酮中配合行为的研究

本文为进一步弄清Dy(NO3)3.3H2O与B15C5在丙酮中的配合行为, 作者用改进的半微量相平衡方法, 研究了Dy(NO3)3.3H2O-B15C5-CH3COCH3三元体系在18℃时的溶解度, 并进一步分离制备配合物, 研究了配合物的红外光谱, 热力学等性质.     

A hot oxidant, 3-NO2Y122 radical, unmasks conformational gating in ribonucleotide reductase

Escherichia coli ribonucleotide reductase is an α2β2 complex that catalyzes the conversion of nucleotides to deoxynucleotides and requires a diferric-tyrosyl radical (Y(?)) cofactor to initiate catalysis. The initiation process requires long-range proton-coupled electron transfer (PCET) over 35 ? between the two subunits by a specific pathway (Y(122)(?)→W(48)→Y(356) within β to Y(731)→Y(730)→C(439) within α). The rate-limiting step in nucleotide reduction is the conformational gating of the PCET process, which masks the chemistry of radical propagation. 3-Nitrotyrosine (NO(2)Y) has recently been incorporated site-specifically in place of Y(122) in β2. The protein as isolated contained a diferric cluster but no nitrotyrosyl radical (NO(2)Y(?)) and was inactive. In the present paper we show that incubation of apo-Y(122)NO(2)Y-β2 with Fe(2+) and O(2) generates a diferric-NO(2)Y(?) that has a half-life of 40 s at 25 °C. Sequential mixing experiments, in which the cofactor is assembled to 1.2 NO(2)Y(?)/β2 and then mixed with α2, CDP, and ATP, have been analyzed by stopped-flow absorption spectroscopy, rapid freeze quench EPR spectroscopy, and rapid chemical quench methods. These studies have, for the first time, unmasked the conformational gating. They reveal that the NO(2)Y(?) is reduced to the nitrotyrosinate with biphasic kinetics (283 and 67 s(-1)), that dCDP is produced at 107 s(-1), and that a new Y(?) is produced at 97 s(-1). Studies with pathway mutants suggest that the new Y(?) is predominantly located at 356 in β2. In consideration of these data and the crystal structure of Y(122)NO(2)Y-β2, a mechanism for PCET uncoupling in NO(2)Y(?)-RNR is proposed.     

配合物[Ln(C6H5COO)2(NO3)(Bipy)]2的合成及表征

镧系含杂环胺三元配合物的研究从六十年代至今已进行了大量探索 ,但四元配合物的研究一直不多 ,并且由于联吡啶 (Ｂｉｐｙ)的配位能力相对较弱 ,有关其四元配合物的研究报道更为少见[1～ 3] 。我们探索合成了 [Ｌｎ(Ｃ6 Ｈ5ＣＯＯ) 2 (ＮＯ3)(Ｂｉｐｙ) ]2 ,且在合成过程中首次观察到了热力学与动力学竞争的现象。1　实验部分1 1　试剂和仪器稀土氧化物纯度超过 99.99% (上海跃龙有色金属有限公司 ) ,其余试剂均为分析纯。ＣａｒｌｏＥｒｂａ 1 1 0 6型元素分析仪 ;ＤＤＳ 1 1Ａ型电导率仪 (1 .0× 1 0 -3ｍｏｌ·Ｌ-1ＤＭＦ) ;日本岛津 47…     

Synthesis,Crystal Structure and Magnetic Properties of a Novel Copper Inverse-9-metallacrown-3 Complex

<正>The reaction of phenyl 2-pyridyl ketoxime(PhPyCNOH)with Cu(NO_3)_2·3H_2O has led to a triangular complex Cu_3(OH)(PhPyCNO)_3(NO_3)·NO_3·H_2O 1 containing the[Cu_3(μ_2-OH)]~(5+) core and possessing the very rare inverse 9-metallacrown-3 motif created by the bridging oximate groups.Crystallographic data for 1:C_(36_H_(30)N_8O_(11)Cu_3,M_r=941.30,monoclinic,space group C2/c,a =18.815(9),b=33.888(15),c=14.307(7)(?),β=118.945(6)°,V=7983(6)(?)~3,Z=8,D_c=1.566 g/cm~3,n=1.652 mm~(-1),F(000)= 3816,R= 0.0644 and wR= 0.1393 for 3468 observed reflections(I2σ(I)).Preliminary variable-temperature magnetic susceptibility studies reveal an antiferroma-gnetically -coupled system showing antisymmetric exchange.     

Novel coordination polymers and structural systematics in the hydrothermal M,M' trans-3(-3-pyridyl)acrylic acid system

The bifunctional ligand trans-3-(3-pyridyl)acrylic acid has been utilized to promote the formation of a novel hetero-metallic [Cu3(C8H6NO2)6Nd2(NO3)6] (1) and two homometallic: [Nd(C8H6NO2)3H2O] (2) and [Cu(C8H6NO2)2] x H2O (3) metal organic framework (MOF) materials. The philosophy here is that a mixture of hard (Nd3+) and softer metal cations will show preference for the carboxylic and pyridyl functional groups, respectively. As such, a 3-D topology 1 has emerged as a stable, heterometallic structure. Efforts to explore structural systematics in this system have led to the synthesis of homometallic end members and hence the formation of a 2-D coordination polymer 2, and a 1-D coordination polymer 3. Presented is an analysis of the effect of a second metal centre on coordination environment, overall structure formation, thermal and luminescence properties.     

Lanthanide complexes of chiral 3 + 3 macrocycles derived from (1R,2R)-1,2-diaminocyclohexane and 2,6-diformyl-4-methylphenol

The enantiopure amine macrocycle H(3)L, as well as the parent macrocyclic Schiff base H(3)L1, the 3 + 3 condensation product of (1R,2R)-1,2-diaminocyclohexane and 2,6-diformyl-4-methylphenol, are able to form mononuclear complexes with lanthanide(III) ions. The lanthanide(III) complexes of H(3)L have been studied in solution using NMR spectroscopy and electrospray mass spectrometry. The NMR spectra indicate the presence of complexes of low C(1) and C(2) symmetry. The (1)H and (13)C NMR signals of the Lu(III) complex obtained from H(3)L have been assigned on the basis of COSY, TOCSY, NOESY, ROESY and HMQC spectra. The NMR data reveal unsymmetrical binding of lanthanide(III) ion and the presence of a dynamic process corresponding to rotation of Lu(III) within the macrocycle. The [Ln(H(4)L)(NO(3))(2)](NO(3))(2)(Ln = Sm(III), Eu(III), Dy(III), Yb(III) and Lu(III)) complexes of the cationic ligand H(4)L(+) have been isolated in pure form. The X-ray analysis of the [Eu(H(4)L)(NO(3))(2)](NO(3))(2) complex confirms the coordination mode of the macrocycle determined on the basis of NMR results. In this complex the europium(III) ion is bound to three phenolate oxygen atoms and two amine nitrogen atoms of the monoprotonated macrocycle H(4)L(+), as well as to two axial bidendate nitrate anions. In the presence of a base, mononuclear La(III), Ce(III) and Pr(III) complexes of the deprotonated form of the ligand L(3-) can be obtained. When 2 equivalents of Pr(III) are used in this synthesis Na(3)[Pr(2)L(NO(3))(2)(OH)(2)](2)NO(3).5H(2)O is obtained. The NMR, ES MS and an X-ray crystal model of this complex show coordination of two Pr(III) ions by the macrocycle L. The X-ray crystal structure of the free macrocycle H(3)L1 has also been determined. In contrast to macrocyclic amine H(3)L, the Schiff base H(3)L1 adopts a cone-type conformation resembling calixarenes.     

掺镁YFeO3固溶体的电导和气敏性能研究

用化学共沉淀法制备了复合氧化物YFeO3镁掺杂固溶体Y1-xMgxFeO3气敏半导体材料,并对其相组成、电导和气敏性能进行了研究。结果表明：Mg2+在YFeO3的A位固溶范围为0糩]x糩0.8;电导测量显示,该p型固溶材料电导突变温度较纯相YFeO3低100℃以上;900℃下灼烧4h所得的Y0.94Mg0.06FeO3粉料制作的元件在257℃时对乙醇灵敏度最高,对4.5*mol/L乙醇的灵敏度高达44;选择性较好,4.5韒ol/LC2H5OH的灵敏度是45*mol/Lpetrol的4.0倍。     

Synthesis, structure, and magnetism of an f element nitrosyl complex, (C5Me4H)3UNO

(C(5)Me(4)H)(3)U, 1, reacts with 1 equiv of NO to form the first f element nitrosyl complex (C(5)Me(4)H)(3)UNO, 2. X-ray crystallography revealed a 180° U-N-O bond angle, typical for (NO)(1+) complexes. However, 2 has a 1.231(5) ? N═O distance in the range for (NO)(1-) complexes and a short 2.013(4) ? U-N bond like the U═N bond of uranium imido complexes. Structural, spectroscopic, and magnetic data as well as DFT calculations suggest that reduction of NO by U(3+) has occurred to form a U(4+) complex of (NO)(1-) that has π interactions between uranium 5f orbitals and NO π* orbitals. These bonding interactions account for the linear geometry and short U-N bond. The complex displays temperature-independent paramagnetism with a magnetic moment of 1.36 μ(B) at room temperature. Complex 2 reacts with Al(2)Me(6) to form the adduct (C(5)Me(4)H)(3)UNO(AlMe(3)), 3.     

Gas-phase nitrosation of ethylene and related events in the C2H4NO+ landscape

The C2H4NO(+) system has been examined by means of quantum chemical calculations using the G2 and G3B3 approaches and tandem mass spectrometry experiments. Theoretical investigation of the C2H4NO(+) potential-energy surface includes 19 stable C2H4NO(+) structures and a large set of their possible interconnections. These computations provide insights for the understanding of the (i) addition of the nitrosonium cation NO(+) to the ethylene molecule, (ii) skeletal rearrangements evidenced in previous experimental studies on comparable systems, and (iii) experimental identification of new C2H4NO(+) structures. It is predicted from computation that gas-phase nitrosation of ethylene may produce C2H4(*)NO(+) adducts, the most stable structure of which is a pi-complex, 1, stabilized by ca. 65 kJ/mol with respect to its separated components. This complex was produced in the gas phase by a transnitrosation process involving as reactant a complex between water and NO(+) (H2O.NO(+)) and the ethylene molecule and fully characterized by collisional experiments. Among the other C 2H 4NO (+) structures predicted by theory to be protected against dissociation or isomerization by significant energy barriers, five were also experimentally identified. These finding include structures CH3CHNO(+) (5), CH 3CNOH (+) ( 8), CH3NHCO(+) (18), CH3NCOH(+) (19), and an ion/neutral complex CH2O...HCNH(+) (12).     

Parallel modes of C-H bond activation initiated by CpMo(NO)(CH2CMe3)(C6H5) at ambient temperatures

The molybdenum nitrosyl complex Cp*Mo(NO)(CH2CMe3)(C6H5) reacts at room temperature via elimination of neopentane or benzene to form the transient species Cp*Mo(NO)(=CHCMe3) and Cp*Mo(NO)(eta2-C6H4). These reactive intermediates effect the intermolecular activation of hydrocarbon C-H bonds via the reverse of the transformations by which they are generated. Thermolysis of Cp*Mo(NO)(CH2CMe3)(C6H5) in pyridine yields the adducts Cp*Mo(NO)(=CHCMe3)(NC5H5) and Cp*Mo(NO)(eta2-C6H4)(NC5H5), and the benzyne complex has been characterized by X-ray diffraction.