Side-on bound dinitrogen complex of zirconium supported by a P2N2 macrocyclic ligand

Reduction of [P 2N 2]ZrCl 2 (where P 2N 2 = PhP(CH 2SiMe 2NSiMe 2CH 2) 2PPh) by KC 8 under N 2 generates the dinuclear dinitrogen complex ([P 2N 2]Zr) 2(mu-eta (2):eta (2)-N 2) and impurities in varying yields depending on the solvent and temperature. The toluene complex [P 2N 2]Zr(eta (6)-C 7H 8) along with a dinuclear species with bridging PC 6H 5 groups is observable. Also observable in the crude reaction mixtures is the mu-oxodiazenido derivative, ([P 2N 2]Zr) 2(mu-eta (2):eta (2)-N 2H 2)(mu-O), due to reaction with trace H 2O. This paper reports the full details of the preparation of ([P 2N 2]Zr) 2(mu-eta (2):eta (2)-N 2) including an improved method that involves reduction at low temperatures in a tetrahydrofuran solvent. Also reported is a reproducible synthesis of the oxodiazenido complex along with the X-ray structures of the dinitrogen complex and the oxodiazenido derivative.     

Cyclometalated rhodium complexes of phenyl- and diphenyl-substituted oxazole and thiazole luminophores

Cyclometaleted rhodium complexes of oxazole and thiazole luminophores [Rh(C??N)₂En]Cl [(C??N)^?, deprotonated forms of 2,5-diphenyloxazole, 2-phenylbenzothiazole, 2-(biphenyl-4-yl)-6-phenylbenzoxazole, and 2-(biphenyl-4-yl)-5-phenyloxazole; En ?? ethylenediamine] were obtained and characterized by the methods of ¹H NMR, IR, and electron absorption and emission spectroscopy. Two cyclometallated ligands in the inner sphere of the complexes are in the cis-C,C positions. Cyclometallating of the luminophores results both in a red shift of intraligand ??-??*-optical transitions (???? ??1.2 kK) as compared to free luminophores and in the appearance of a long-wave band (??_max 376?C392 nm) of a mixed nature: metal-ligand charge transfer/intraligand transition. Alongside with the internal conversion to a low-energy state of the metal-ligand charge transfer/ intraligand transition, the emission degradation of photoexcitation energy results in the intraligand ??-??*-fluorescence of the complexes (??_max 390?C423 nm) at room temperature.     

苯基取代的环戊二烯基锆化合物的合成及催化乙烯聚合

一系列苯基取代的环戊二烯配体在甲苯中相继与丁基锂及ZrCl4作用，生成相 应的苯基取代的茂金属化合物，通过^1H NMR，MS和元素分析表征了化合物的分子 结构，并研究了在MAO（甲基铝氧烷的助催化下，化合物对乙烯聚合的催化性能， 结果发现单苯基取代茂金属化合物的催化活性和产物聚乙聚的分子量都随聚合温度 的升高而增大。     

Synthesis and characterization of some octahedral transition metal complexes with phenyl-2-picolylketone thiosemicarbazone

Summary A series of transition metal complexes with phenyl-2-picolylketone-thiosemicarbazone, LH, of the general formula [ML₂]Cl_nmH₂O, (M=Cr³⁺, Mn²⁺, Fe²⁺, Rh³⁺, Ir³⁺ or Ru³⁺; n=0 or 1 and m=1,2 or 3) have been prepared and characterized. Magnetic and spectral (electronic and vibrational) data are commensurate with an octahedral ligand field for all complexes. The variable temperature magnetic moment shows that the iron(II) complex exists in a temperature-dependent high-spinlow-spin equilibrium. The far i.r. spectra show that the strength of the M–S bond follows the order: Mn²⁺ 2+3+3+3+3+. The various ligand field parameters, Dq, B' and are calculated.     

腰接型侧链液晶弹性体研究进展

液晶弹性体是交联型液晶大分子,兼具液晶取向有序性和交联聚合物熵弹性等特性,在传感器、触发器、微流体装置和仿生器件等方面具有很好的应用前景.制备液晶弹性体的微结构,探索其独特的刺激响应性,是目前液晶弹性体研究的重要方向.侧链液晶弹性体的液晶相态类型取决于其液晶基元和主链的连接方式.腰接型侧链液晶弹性体倾向于形成向列型液晶相,具有较快的响应速度和形变程度,是一类独特的液晶弹性体.本文重点介绍腰接型液晶弹性体微结构(如微米柱、微米线等)的制备;利用金纳米粒子的光热转换效应,实现液晶弹性体光响应性的新途径;以及腰接型侧链液晶弹性体仿生微结构的功能性等.同时还对该领域的发展前景进行了展望.     

Polarographic behaviour of phenyl-2-picolylketone-2-pyridylhydrazone and its copper (II) complexes

The polarographic behaviour of phenyl-2-picolylketone-2-pyridylhydrazone, PPKPyH, has been studied in aqueous-ethanol mixtures of different pH's using DC and DP polarographic method. In the pH range 3.7–6.2, the observed single irreversible reduction wave is assigned to the splitting of the N—N bond and reduction of C=N centre. In alkaline medium, a second wave appears at more negative potential due to the reduction of the phenyl-2-picolylketone which is formed from the hydrolysis of PPKPyH. The optimum conditions for the analytical determination of PPKPyH was reported. Differential pulse polarography have been used to elucidate the complexation reaction between PPKPyH and copper(II) in unbuffered solutions. Two complexes are formed with log ₁ = 4.42 and log ₂ = 8.87.     

Thermal investigations on naturally bound glycosaminoglycan complexes

A derivatograph has been used successfully for the investigation of glycosaminoglycan, proteins, as well as their lipid complexes in native biological tissues. Details and discussion of these problems are available in the papers cited in the references.

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Zusammenfassung Der Derivatograph wurde zur Untersuchung von Glycoseaminoglycan, Proteinen und ihrer Lipidkomplexen auch in nativen biologischen Stoffen mit Erfolg angewandet. Näheres und Besprechung dieser Probleme sind in den in der Literatur angegebenen Veröffentlichungen zu finden.

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Résumé La méthode de la dérivatographie a été appliquée avec succès à l'examen de Glycoseaminoglycane de protéines et leurs complexes avec lipides dans des tissus natifs biologiques.

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Side-on liquid crystal polyacrylate in Langmuir-Blodgett films

A side-on fixed liquid crystal polyacrylate has been investigated in Langmuir and Langmuir-Blodgett (LB) films. High in-plane orientation of the mesogenic groups has been observed within the LB multilayers, showing the ability of the LB technique to align a liquid crystal. The analysis of the in-plane order versus the dipping speed suggests some self-aggregation of the polymer in the monolayer. Within these aggregates, the molecular orientation (in-plane and out-plane) has been deduced from infrared dichroism experiments; the mesogenic group lies mainly parallel to the dipping direction and relatively flat on the substrate. This alignment of the polymer is however partially lost with time, leading to materials with less in-plane anisotropy.     

Thermal and structural characterization of copper(II) complexes with phenyl-2-pyridylketoxime (HPPK)

Journal of Thermal Analysis and Calorimetry - Copper(II) complexes of different nuclearity with phenyl-2-pyridylketoxime (HPPK), such as mononuclear [Cu(HPPK)(PPK)X], whereby...     

Electron capture dissociation of weakly bound polypeptide polycationic complexes

We have previously reported that, in electron capture dissociation (ECD), rupture of strong intramolecular bonds in weakly bound supramolecular aggregates can proceed without dissociation of weak intermolecular bonds. This is now illustrated on a series of non-specific peptide-peptide dimers as well as specific complexes of modified glycopeptide antibiotics with their target peptide. The weak nature of bonding is substantiated by blackbody infrared dissociation, low-energy collisional excitation and force-field simulations. The results are consistent with a non-ergodic ECD cleavage mechanism.     

Anharmonicity of weakly bound M(+)-H2 complexes

The anharmonicity of weakly bound complexes is studied using the vibrational self-consistent field (VSCF) approach for a series of metal cation dihydrogen (M(+)-H(2)) complexes. The H-H stretching frequency shifts of M(+)-H(2) (M(+) = Li(+), Na(+), B(+), and Al(+)) complexes are calculated with the coupled-cluster method including all single and double excitations with perturbative triples (CCSD(T)) level of theory with the cc-pVTZ basis set. The calculated H-H stretching frequency of Li(+)-H(2), B(+)-H(2), Na(+)-H(2), and Al(+)-H(2) is red-shifted by 121, 202, 74, and 62 cm(-1), respectively, relative to that of unbound H(2). The calculated red shifts and their trends are in good agreement with the available experimental and previously calculated data. Insight into the observed trends is provided by symmetry adapted perturbation theory (SAPT).     

Extension of the ring oxygen helicity rule to the phenyl- and phenyl-1-thio-glycosides

Circular Dichroism (CD) of the phenyl- and phenyl-1-thio-β(or α)-$\text{d}$-glycosides were studied. The sign and the rotational strength of Band C, the shortest and the strongest band between 180～210 nm, were associated with the anomeric configuration and conformation in the same manner as the σ→σ* band of the ring oxygen in the 1-alkyl- and 1-alkyl-thio-glycosides. This result suggested that the $\text{ring oxygen helicity rule}$ could be extended to the phenyl- and phenyl-1-thio-glycosides.     

Preparation and catalytic properties of chitosan bound Schiff base copper complexes

Chitosan, a natural polymer, bound Schiff base copper complexes CT‐She‐Cu, CT‐o‐Bel‐Cu, CT‐m‐Bel‐Cu were prepared and characterize by inductively coupled plasma (ICP), FT‐IR and X‐ray photoelectron spectroscopy (XPS). Their catalytic activity in the oxidation of cyclohexene with molecular oxygen was studied. All the complexes have catalytic activity and the main oxidation products are 2‐cyclohexene‐ol, 2‐cyclohexene‐one and cyclohexene hydroperoxide, which were measured by gas chromatography/mass spectroscopy (GC/MS) and GC/IR. CT‐m‐Bel‐Cu was selected to study the influence of reaction temperature, amount of catalyst and additives such as acid and base on the oxidation of cyclohexene systematically. Copyright © 2004 John Wiley & Sons, Ltd.     

Hydrogenation catalysts containing phosphine complexes of palladium bound to silica

Catalysts have been obtained containing surface phosphine palladium complexes on SiO₂. A comparison has been made between the catalytic properties of the complexes obtained and those of the catalysts containing supported palladium; it has been shown that the catalysts containing supported palladium complexes possess several features characteristic of homogeneous catalytic systems.

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Side-on fixed polysiloxanes and 'diluted' copolysiloxanes with nematic and smectic C phases

The influence of the molecular parameters of side-on fixed liquid crystal polymers (LCP), namely the spacer length, the aliphatic tail length and the proportion of mesogenic groups ('dilution' effect), on the mesomorphic, thermodynamic and structural properties of the nematic and smectic C phases has been studied. This shows in particular the stabilization of the SmC phase on increasing the terminal chain lengths. Moreover, this paper provides evidence for an original behaviour in the SmC organization of side-on LCP with a nonstructural monotonous evolution of the thermodynamic and properties with the 'dilution'. Finally, a comparison with side-end LCP can be established : the question of the participation of the polymer backbone in the smectic organization in side-on LCP is raised.     

Reactions of phenyl- and trimethylsilylphenylphosphines with thiobenzophenone

Conclusions The reaction of phenyl- and trimethylsilylphenylphosphines with thiobenzophenone with a 11 reagent ratio proceeds with the formation of secondary phosphines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2116–2117, September, 1984.     

Iridium(III) complexes as polymer bound oxygen sensors

New luminescent oxygen sensors have been prepared by covalent attachment of iridium complex luminophores to a silicone polymer. The oxygen sensor properties of these novel materials were compared to related sensors in which the luminophore is dispersed within the polymer matrix. Covalently bound luminophore materials showed increased sensitivity to oxygen over dispersions in pure silicone polymer as well as in blends with polystyrene, which was added to improve the mechanical properties of the material.     

The synthesis and molecular structures of two cyclobutadienecobalt complexes formed by the reaction between π-cyclopentadienyldicarbonylcobalt and phenyl-2-thienylacetylene

The reaction between h⁵-cyclopentadienyldicarbonylcobalt and phenyl-2-thienylacetylene in refluxing xylene has been found to produce 78% yield of (h⁵-cyclopentadienyl)(h⁴-diphenyldi-2-thienylcyclobutadiene) cobalt, as well as lesser amounts of a cyclotrimerization product, triphenyltri-2-thienylbenzene, and three isomeric cyclopentadienonecobalt complexes. A single crystal X-ray structural study intended to confirm the disposition of the phenyl and thienyl substituents of the cyclobutadiene ring in the first compound was carried out. The results are inconclusive since there is disorder of these groups in the crystalline lattice. The most likely model involves a mixture of cis and trans isomers plus phenylthienyl disorder. The atoms of the (h⁵-C₅H₅)Co(C₄) moiety are well behaved crystallographically and have molecular parameters which are within accepted values of recent determinations not plagued by disorder or uncertainty of isomeric purity.A minor biproduct, resulting from the apparent coreaction of phenyl-2-thienyl-acetylene and diphenyldiacetylene with h⁵-cyclopentadienyldicarbonylcobalt, has also been identified by spectral and X-ray diffraction techniques as the novel complex bis [(h⁵-cyclopentadienyl)(h⁴-trans-diphenyl-2-thienylcyclobutadienyl)-cobalt]. The crystallographic study of this compound also revealed disorder in the thienyl groups but it is not as severe as that found for the major product.