AU(DIEN)Cl]Cl(2): Exchange Phenomena Observed by H and C NMR Spectroscopy

The solution behaviour of the square-planar gold(III) complex [Au(dien)Cl]Cl(2) (dien = 1,5- diamino-3-azapentane) was investigated by (13)H and (13)C NMR spectroscopy. We have found that (1)H NMR spectra of [Au(dien)Cl] Cl(2) are characterised by exchange behaviour over the whole pH range, and some exchange effects are also seen in (13)C NMR spectra of the deprotonated hydroxo derivative of the complex in alkaline solution. An exchange rate of > 378 s(-1) was determined from (1)H NMR spectra at pH *(2) (coalescence temperature (40)C degrees ). In slightly acidic solutions of the complex, (1)H chemical shifts are in accordance with the known deprotonation of the central amine group of the complexed diethylenetriamine ligand. In (13)C NMR spectra, two separate sets of resonances are observed for the chloro and the hydroxo complex of gold(III) diethylenetriamine. The hydroxo complex [Au(dien-H)OH(+) shows exchange effects in (13)C NMR spectra. Variable temperature studies show the carbon atoms next to the central secondary amine to be inequivalent and each present in two different environments that are in intermediate to fast exchange on the NMR time-scale.     

Epoxidation of natural propenylbenzenes catalyzed by [FeIII(Salen)Cl] and [FeIII(TPP)Cl]

Epoxidation of natural propenylbenzenes (safrol, isosafrol, anethol, eugenol and isoeugenol) was carried out using iron complexes as catalysts ([Fe^III(TPP)Cl] and [Fe^III(Salen)Cl] · H₂O, where TPP = 5, 10, 15, 20-meso-tetraphenylporphyrin and Salen = N,N′-(salicylaldehyde)ethylenediamine) in presence of hydrogen peroxide 30% and glacial acetic acid. Reaction products were identified by gas chromatography and satisfactory yields were obtained. Quantitative conversion of isosafrol to the corresponding epoxide was achieved in presence of [Fe^III(TPP)Cl] as catalyst.     

Oxidation of cyclohexane promoted by [Fe(III)(Salen)Cl] and [Mn(III)(Salen)Cl]

Salen complexes of iron(III) and manganese(III) were synthesized and employed as catalysts in the oxidation of cyclohexane, using hydrogen peroxide and tert–butylhydroperoxide. The reactions were carried out in acetonitrile at room temperature. The catalysts were characterized by infrared and Mössbauer spectroscopy, elemental analysis, conductivity and cyclic voltammetry. Conversions up to 10.2% (4.2% and 6.0% yields for cyclohexanol and cyclohexanone, respectively) were obtained for the system [Fe(III)(Salen)Cl]/tBuOOH.     

离子液体([bmim]Cl)促进下醛基香豆素的Reformatsky反应

在离子液体氯化1-丁基-3-甲基咪唑([bmim]Cl)存在下,Zn粉活化的α-溴代苯乙酮类化合物与6-甲基-4-醛基香豆素发生Reformatsky反应,合成出三种香豆素取代的β-羟基酮类化合物。通过IR和1 H NMR对所合成的化合物进行了结构表征。实验结果表明,离子液体[bmim]Cl能够促进溴代苯乙酮与醛基香豆素的Reformatsky反应,并以较高产率得到香豆素取代的β-羟基酮类化合物。离子液体[bmim]Cl经处理后可循环利用,并且效率较高。     

Investigations of the Binding of [Pt2(DTBPA)Cl2](II) and [Pt2(TPXA)Cl2](II) to DNA via Various Cross-Linking Modes

We have constructed models for a series of platinum-DNA adducts that represent the binding of two agents, [Pt₂(DTBPA)Cl₂](II) and [Pt₂(TPXA)Cl₂](II), to DNA via inter- and intra-strand cross-linking, and carried out molecular dynamics simulations and DNA conformational dynamics calculations. The effects of trans- and cis-configurations of the centers of these di-nuclear platinum agents, and of different bridging linkers, have been investigated on the conformational distortions of platinum-DNA adducts formed via inter- and intra-strand cross-links. The results demonstrate that the DNA conformational distortions for the various platinum-DNA adducts with differing cross-linking modes are greatly influenced by the difference between the platinum-platinum distance for the platinum agent and the platinum-bound N7–N7 distance for the DNA molecule, and by the flexibility of the bridging linkers in the platinum agent. However, the effects of trans/cis-configurations of the platinum-centers on the DNA conformational distortions in the platinum-DNA adducts depend on the inter- and intra-strand cross-linking modes. In addition, we discuss the relevance of DNA base motions, including opening, shift and roll, to the changes in the parameters of the DNA major and minor grooves caused by binding of the platinum agent.     

二茂铁烯丙基卡宾钯络合物的合成及催化性能

采用一锅法将咪唑盐对二茂铁烯丙基钯二聚体I在室温下进行解聚，避免了使用不稳定的卡宾，简便、高效地合成了二茂铁烯丙基卡宾钯络合物II。通过IR，1H NMR，13C NMR，MS，HRMS和X射线单晶衍射对其结构进行鉴定。络合物II对空气和湿气稳定，且对芳基氯代物参与的Suzuki-Miyaura 偶联反应和Buchwald-Hartwig胺化反应展现较高的催化活性。在反应温度70 oC，0.4 mol％络合物II催化芳基氯代物与芳基硼酸的偶联反应时，取得95-100%收率；在反应温度100 oC，0.5 mol％钯络合物II催化氯苯与多样化胺的偶联反应时，也获得中等至好的的收率。     

CH3 and Cl2 coadsorbed on Si/Cu(100)

X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) studies were used to investigate the reactions of coadsorbed CH₃ and Cl₂ on Si/Cu(100). TPD results showed that the individual exposure of Si/Cu(100) to CH₃ and Cl₂ resulted primarily in the desorption of (CH₃)₃SiH and SiCl₄, respectively. Coadsorption of CH₃ and Cl₂ at specific surface concentrations on Si/Cu(100) resulted in the desorption of (CH₃)_4-xSiCl_x (x ranges from 1 to 3) species. The relative surface concentration of CH₃ and Cl (resulting from Cl₂ dissociation), however, controlled the stoichiometry of the methylchlorosilane product. XPS results suggested that more Si was removed from the Si/Cu(100) surface as gaseous product when CH₃ and Cl₂ were coadsorbed on the surface than when CH₃ and Cl₂ were adsorbed alone.     

Non-photochemical synthesis of Re(diimine)(CO)2(L)Cl (L = phosphine or phosphite) compounds

The synthesis and characterization of a series of compounds of the type Re(diimine)(CO)₂(L)Cl (where L = P(OEt)₃, PMe₃) is reported. The non-photochemical ligand substitution (non-PLS) utilizes the trans-labilizing effect of phosphorus ligands to facilitate carbonyl replacement. The non-PLS pathway leads to good yields (> 60%) of single isomer products, comparing favorably to the lower yield, mixed isomer products of analogous PLS pathways. The substitution of a carbonyl group by a phosphine/phosphite ligands shifts absorption further into the visible region without diminishing molar absorptivity. The synthesis presented provides a general facile ligand substitution pathway for related light-sensitive neutral rhenium/manganese carbonyl halide compounds.     

均相Nd(vers)3/Al(i-Bu)2H/Al(i-Bu)2Cl催化聚合异戊二烯

采用A l(i-Bu)2C l(简称C l)、Nd(vers)3(简称Nd)和A l(i-Bu)2H(简称A l)在少量异戊二烯(Ip)存在下,Nd与A l在50℃下反应后,再与C l作用,可配制成均相高效催化剂体系。考察了Nd和A l二组分陈化时间、Nd和A l、C l三组分陈化时间、A l/Nd(摩尔比)、C l/Nd(摩尔比)、聚合温度及溶剂对催化剂相态和Ip聚合的影响。结果表明,上述反应因素对催化剂的相态和产物微观结构均无影响,聚异戊二烯(PI)的顺式-1,4-结构摩尔分数在95.0%以上;Nd和A l二组分陈化时间应控制在10 m in之内;Nd、A l和C l三组分陈化时间对PI收率无影响。当A l/Nd为15或C l/Nd为1.0时,均相Nd/A l/C l催化剂体系仍具有高的聚合活性。当聚合温度为30~70℃时,提高温度可提高PI收率;以环己烷替代或部分替代己烷可提高PI收率。     

Synthesis of semiconducting polyphenylacetylene catalyzed by Ni(MeCN)6(BF4)2/AlEt2Cl

Summary Phenylacetylene (PhA) is polymerized by the dicationic nickel complex Ni(MeCN)₆(BF₄)₂ associated with AlEt₂Cl as co-catalyst. The production of 200g of polymer per gram of nickel per hour represents a typical activity of this system. Under our experimental conditions, the polymer displays an exclusive trans structure. The molecular weight distribution of the polymer is polymodal (5000 g.mol⁻¹ and 200 g.mol⁻¹). The highest average molecular weight fraction (5000 g. mol⁻¹) represents the highest published value for polyphenylacetylene (PPA) where a nickel catalyst is employed. The electrical conductivities vary between 10⁻⁷ and 10⁻¹⁶ S.cm⁻¹, and are characteristic of a semi-conductor polymer. Equivalent values are cited in the literature only in the case of doped PPA. Experimental observations enabled us to propose a mechanism for the formation of the active species through the reaction of Ni(MeCN)₆(BF₄)₂ with AlEt₂Cl. Received: 13 September 2001/Revised version: 10 January 2002/ Accepted: 11 January 2002     

CpMo(CO)3Cl as a precatalyst for the epoxidation of olefins

The tricarbonyl complex CpMo(CO)₃C1 was found to act as a precatalyst for the reaction of tert-butyl hydroperoxide and olefins to yield the corresponding epoxides and diols. Under the reaction conditions, oxidative decarbonylation leads to the formation of the dioxo complex CpMoO₂Cl. The catalytic recyclability and the effect of temperature on the catalytic results have been examined, and a reaction mechanism proposed, supported by kinetic modelling.     

The metal-chain complexes (X)[Os(CO)3(CNBut)]3Mn(CO)5 (X=Cl,Br, I)

In what is a new metal-chain forming reaction, (X)[Os(CO)₃(CNBu^t)]₃Mn(CO)₅ (X=Cl, Br, I) complexes have been prepared by the successive addition of Os(CO)₄(CNBu^t) to Mn(CO)₅(X) in hexane. The crystal structure of the iodo derivative reveals it to contain an approximately linear Os₃ Mn chain of metal atoms.     

配位化合物Cu(p-tol)2Cl2标准生成焓的测定

使用具有恒定温度环境的反应热量计,以溶解热法及针对配位反应所设计的热化学循环,得到该反应的标准反应焓△ｒＨθｍ（２９８．１５Ｋ）＝－２７．９２４ｋＪ·ｍｏｌ－１,并求得配合物Ｃｕ（ｐ－ｔｏｌ）２Ｃｌ２的标准生成焓,其值推荐为△ｆＨθｍ［Ｃｕ（ｐ－ｔｏｌ）２Ｃｌ２,ｓ］＝－３４３．３７４ｋＪ·ｍｏｌ－１。     

X-ray excited CsPb(Cl,Br)3 perovskite quantum dots-glass composite with long-lifetime

CsPbX₃ (X = Cl, Br, I) perovskite quantum dots (QDs) have emerged as a kind of brand-new X-ray scintillator with high performance. Herein, following the phase transformation from amorphous to crystalline, CsPb(Cl,Br)₃ QDs are in-situ precipitated from a borate glass matrix. It is demonstrated for the first time that the perovskite QDs-glass composite yields radioluminescence (RL), showing X-ray excited RL ∼1/18 to that of commercial Bi₄Ge₃O₁₂ (BGO) single crystal. The color of RL is adjustable, dependent on the anionic species. Evidently, the high power X-ray induced damage in material is recoverable just by re-heating it at glass transition temperature. This work highlights the partial settlement of tough issues in perovskite QDs as scintillators, such as, physical stability, service lifetime, Pb-toxicity, and production scale.     

配合物Ni(p-tol)2Cl2标准生成焓的测定

使用具恒定温度环境的反应热量计,以溶解热法及针对配位反应所设计的热化学循环,得到该反应的标准反应焓, 并求得配合物Ｎｉ （ｐ－ｔｏｌ）２Ｃｌ２ 的标准生成焓。     

The terminal binding of base mismatched oligonucleotide d(CCGAATGAGG)2 by [Co(phen)2(DPQ)]Cl3

The binding of the complex [Co(phen)₂(DPQ)]Cl₃ to the decanucleotide d(CCGAATGAGG)₂ containing two pairs of sheared G:A mispairs was studied by 2D-NMR. There appear many ¹H NOE cross-peaks from the complex to the oligonucleotide. The results indicate that the complex, with DPQ, intercalates into the oligonucleotide via its terminal base pairs from the minor groove, which further proved our previous conclusion.     

Ferroelectric phase transitions of (CH3NH3)5Bi2Cl11

The spontaneous polarization of (CH₃NH₃)₅Bi₂Cl₁₁ single crystals was measured in the range 80-315 K revealing the existence of a ferro-ferroelectric type transition at 170 K.     

配合物Co(p-tol)2Cl2标准生成焓的测定

使用具恒定温度环境的反应热量计,以溶解热法及针对配位反应所设计的热化学循环,得到反应的标准反应焓,并求得配合物Co(p-tol)2Cl2的标准生成焓.     

Zn(py)2Cl2的合成、晶体结构及发光性能研究

使用乙醚作为溶剂,合成了Zn(Ⅱ)配合物Zn(py)<,2>Cl<,2>,其结构经过X-射线单品衍射、红外光谱分析等手段进行结构表征.采用循环伏安法研究了配合物Zn(py)<,2>Cl<,2>在DMF和DMSO溶液中的电化学性质,可以观察到1个单电子氧化还原过程,对应于配合物分子内Zn<'2+>/Zn<'+>电对的电子...     

Distinct composite structure and properties of Eu(phen)2Cl3(H2O)2 in poly(methyl methacrylate) and polyvinylpyrrolidone

The luminescent europium complex Eu(phen)₂ Cl₃(H₂O)₂ (phen refers to 1,10‐phenanthroline) was doped in poly(methyl methacrylate) (PMMA) and polyvinylpyrrolidone (PVP), respectively. The formed composite systems with different molar ratios of C?O groups in polymers and Eu ions were characterized by X‐ray diffractometry (XRD), FTIR, and photoluminescent (PL) spectroscopy and lifetime measurement. The XRD diffractograms show that the composites of PMMA/Eu(phen)₂Cl₃(H₂O)₂ and PVP/Eu (phen)₂Cl₃(H₂O)₂ have crystalline and amorphous structures, respectively, arising from different interactions between the polymers and the complex, as revealed by FTIR spectra. This leads to distinct luminescent characteristics arising from the ⁵D₀→⁷F_J transitions of Eu(III) ion (J = 0–4). For the composite systems of PMMA/complex, the characteristics of the emission lines change with decreasing molar ratios of C?O/Eu and approach that of the pure complex; whereas the composite systems of PVP/complex have similar spectral features, regardless of the molar ratios, differing from that of the pure complex. The polymer matrices have a substantial influence on the structure and properties of the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3524–3530, 2004