bluuebunny/crossref_metadata_2025 huggingface dataset:
The Characterisation of Molecular Alkali‐Metal Azides
Authors: Ogden J. Steven , Dyke John M. , Levason William , Ferrante Francesco , Gagliardi Laura
Published: February 2006

Matrix isolation infrared (IR) studies have been carried out on the vaporisation of the alkali‐metal azides MN3 (M = Na, K, Rb and Cs). The results show that under high vacuum conditions, molecular KN3, RbN3 and CsN3 are present as stable high‐temperature vapour species, together with variable amounts of nitrogen gas and the corresponding metal atoms. The characterisation of these molecular azides is supported by ab initio molecular orbital calculations and density functional theory (DFT) calculations, and for CsN3 in particular, by the detection of the isotopomers Cs(14N15N14N) and Cs(15N14N14N). The IR spectra are assigned to a “side‐on” (C2v) structure by comparison with the spectral features predicted both by vibrational analysis and calculation. The most intense IR features for KN3, RbN3 and CsN3 isolated in nitrogen matrices lie at 2005, 2004.4 and 2002.2 cm−1, respectively, and correspond to the N3 asymmetric stretch. The N3 bending mode in CsN3 is identified at 629 cm−1. An additional feature routinely observed in these experiments occurred at approximately 2323 cm−1 and is assigned to molecular N2, perturbed by the close proximity of an alkali‐metal atom. The position of this band appeared to show very little cation dependence, but its intensity correlated with the extent of sample thermal decomposition.
Titanium Phosphonate Porous Materials Constructed from Dendritic Tetraphosphonates
Authors: Vasylyev Maxym V. , Wachtel Ellen J. , Popovitz‐Biro Ronit , Neumann Ronny
Published: February 2006

An organic–inorganic hybrid material, TPPhA‐Ti, was constructed by non‐hydrolytic condensation of a dendritic tetrakis‐1,3,5,7‐(4‐phosphonatophenyl)adamantane precursor and titanium(IV) isopropoxide. One preparative pathway yielded insoluble materials with a Ti/P ratio of ∼1 which was confirmed by a combination of FT‐IR, TGA, and EDS measurements. N2 sorption experiments showed that TPPhA‐Ti is a porous solid (micropores ∼13 Å; mesopores ∼38 Å) with a high surface area, ∼550 m2 g−1. The structure and morphology of the TPPhA‐Ti as investigated by transmission and scanning electron microscopy showed a layered‐type material. Additional X‐ray diffraction data suggest a paracrystalline material; an optimization of possible molecular arrangements of TPPhA‐Ti was simulated that was in agreement with the experimental data. A second preparative pathway yielded a Ti oxide–phosphonate with a Ti/P ratio of ∼3.4. Both TEM and SEM revealed that hollow nanospheres were formed with diameters of ∼180–300 nm.
Hexa‐ and Octacoordinate Carbon in Hydrocarbon Cages: Theoretical Design and Characterization
Authors: Wang Yang , Huang Yuanhe , Liu Ruozhuang
Published: February 2006

A new series of hydrocarbon cages containing hexa‐ and octacoordinate carbon centers were designed theoretically by performing DFT calculations at the B3 LYP/6–311+G** level. Among these non‐classical structures that were found to still obey the 8e rule, the two tetracations with octacoordinate carbons may be the first examples found in pure hydrocarbons. Structural characteristics, as well as thermodynamic and kinetic stabilities, were also investigated theoretically for these two octacoordinate tetracations. These hydrocarbon compounds containing hypercoordinate carbon centers provide a challenge for synthetic organic chemists.
Oxidation Chemistry of Poly(ethylene glycol)‐Supported Carbonylruthenium(II) and Dioxoruthenium(VI) meso‐Tetrakis(pentafluorophenyl)porphyrin
Authors: Zhang Jun‐Long , Huang Jie‐Sheng , Che Chi‐Ming
Published: February 2006

[RuII(F20‐tpp)(CO)] (1, F20‐tpp=meso‐tetrakis(pentafluorophenyl)porphyrinato dianion) was covalently attached to poly(ethylene glycol) (PEG) through the reaction of 1 with PEG and sodium hydride in DMF. The water‐soluble PEG‐supported ruthenium porphyrin (PEG‐1) is an efficient catalyst for 2,6‐Cl2pyNO oxidation and PhINTs aziridination/amidation of hydrocarbons, and intramolecular amidation of sulfamate esters with PhI(OAc)2. Oxidation of PEG‐1 by m‐CPBA in CH2Cl2, dioxane, or water afforded a water‐soluble PEG‐supported dioxoruthenium(VI) porphyrin (PEG‐2), which could react with hydrocarbons to give oxidation products in up to 80 % yield. The behavior of the two PEG‐supported ruthenium porphyrin complexes in water was probed by NMR spectroscopy and dynamic light‐scattering measurements. PEG‐2 is remarkably stable to water. The second‐order rate constants (k2) for the oxidation of styrene and ethylbenzene by PEG‐2 in dioxane–water increase with water content, and the k2 values at a water content of 70 % or 80 % are up to 188 times that obtained in ClCH2CH2Cl.
Tris(pyridylmethylamino)cyclotriguaiacylene Cavitands: An Investigation of the Solution and Solid‐State Behaviour of Metallo‐Supramolecular Cages and Cavitand‐Based Coordination Polymers
Authors: Sumby Christopher J. , Fisher Julie , Prior Timothy J. , Hardie Michaele J.
Published: February 2006

The synthesis of the three isomeric tris(pyridylmethylamino)cyclotriguaiacylene cavitands is reported, along with the crystal structures of the 2‐ and 4‐pyridyl derivatives. The generality of a previously described [Ag2{tris(3‐pyridylmethylamino)cyclotriguaiacylene}2]2+ dimeric capsule motif and the [Ag4{tris(4‐pyridylmethylamino)cyclotriguaiacylene}4]4+ tetrahedron with several silver salts was confirmed in the solid state and the corresponding solution species were investigated by NMR spectroscopy. Host–guest interactions in these systems have been probed and these interactions are demonstrated to alter and influence the self‐assembly outcome of the reaction. Notably, introduction of larger glutaronitrile guest molecules to the [Ag4L4]4+ tetrahedron system prevents formation of the tetrahedral structure, resulting instead in the formation of a 4.82 coordination network in the solid state. In the absence of templating acetonitrile guests in the [Ag2(3)2]2+ capsule system, formation of a cage‐based one‐dimensional coordination polymer is observed.
Psychotherapy for PTSD in the community: reported prototypical treatments
Authors: Schottenbauer Michele A. , Arnkoff Diane B. , Glass Carol R. , Gray Sheila Hafter
Published: February 2006

Therapists who identified themselves primarily with psychodynamic/psychoanalytic or cognitive–behavioral theoretical orientations were recruited through professional organization online listservs. They were randomly presented one of four brief case studies, describing variations on traumatic stress. Participants then completed a Psychotherapy Process Q‐sort to describe quantitatively their ideal treatment of the given patient. Results indicated significant heterogeneity among clinicians. Among clinicians who indicated that their primary theoretical orientation was psychodynamic, three prototypical treatments were discovered, and among clinicians who indicated that their primary theoretical orientation was cognitive–behavioral, four prototypical treatments were found. Overall, the prototypes in the current study were correlated with, but not identical to, prototypes of psychodynamic, cognitive–behavioral or interpersonal therapy developed in previous studies based on experts' ratings. Our findings suggest that there may be much greater heterogeneity in treatment of trauma among clinicians in the community than might be assumed by the theoretical orientations they espouse. Copyright © 2006 John Wiley & Sons, Ltd.
Elementary Many‐Particle Processes in Plasma Microfields
Authors: Romanovsky M. Yu. , Ebeling W.
Published: February 2006

The effect of electric and magnetic plasma microfields on elementary many‐body processes in plasmas is considered. As detected first by Inglis and Teller in 1939, the electric microfield controls several elementary processes in plasmas as transitions, line shifts and line broadening. We concentrate here on the many‐particle processes ionization, recombination, and fusion and study a wide area of plasma parameters. In the first part the state of art of investigations on microfield distributions is reviewed in brief. In the second part, various types of ionization processes are discussed with respect to the influence of electric microfields. It is demonstrated that the processes of tunnel and rescattering ionization by laser fields as well as the process of electron collisional ionization may be strongly influenced by the electric microfields in the plasma.

The third part is devoted to processes of microfield action on fusion processes and the effects on three‐body recombination are investigated. It is shown that there are regions of plasma densities and temperatures, where the rate of nuclear fusion is accelerated by the electric microfields. This effect may be relevant for nuclear processes in stars. Further, fusion processes in ion clusters are studied. Finally we study in this section three‐body recombination effects and show that an electric microfield influences the three‐body electron‐ion recombination via the highly excited states.

In the fourth part, the distribution of the magnetic microfield is investigated for equilibrium, nonequilibrium, and non‐uniform magnetized plasmas. We show that the field distribution in a neutral point of a non‐relativistic ideal equilibrium plasma is similar to the Holtsmark distribution for the electrical microfield. Relaxation processes in nonequilibrium plasmas may lead to additional microfields. We show that in turbulent plasmas the broadening of radiative electron transitions in atoms and ions, without change of the principle quantum number, may be due to the Zeeman effect and may exceed Doppler and Stark broadening as well. Further it is shown that for optical radiation the effect of depolarization of a linearly polarized laser beams propagating through a magnetized plasma may be rather strong. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highly precise estimation scheme for remote video PSNR using spread spectrum and extraction of orthogonal transform coefficients
Authors: Kawada Ryoichi , Sugimoto Osamu , Koike Atsushi , Wada Masahiro , Matsumoto Shuichi
Published: February 2006

With the widespread use of the digital transmission of TV signals, it is highly desirable to establish a remote monitoring scheme for video transmission quality. As a monitoring scheme for the digital video quality in the actual transmission, the reduced reference (RR) scheme is considered promising: in this scheme the feature parameters of the original picture are extracted and transmitted for comparison with the parameters in the receiver. Consequently, this paper proposes an RR‐type picture quality‐monitoring scheme which can provide highly precise remote estimation of the PSNR of the received picture. In the proposed scheme, the sent and received signals are whitened by spectrum spreading, and orthogonal transformation is applied to the results. The transform coefficients are extracted and transmitted through the monitoring link. Due to the whitening process, highly precise PSNR estimation is realized, even though only a small number of coefficients are extracted. In order to make the whitening effective, the degradation must be distributed as uniformly as possible in the transform block. In order to deal with local picture degradation due to channel error and other factors, multiplication by a PN sequence (spatial spreading) and the inverse orthogonal transform are applied in the transform domain, resulting in effective spreading and helping to improve the precision of PSNR estimation. The Walsh–Hadamard transform, which is easy to implement, is used as the orthogonal transform. By using the proposed scheme, a PSNR estimation error of approximately ±0.1 to 0.3 dB for a monitoring link rate of 40 kbit/s is obtained, which meets practical requirements for highly precise estimation. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(6): 51–62, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20188
High‐resolution RCS measurement using MUSIC algorithm
Authors: Yamazaki Hiroyoshi , Murasaki Tsutomu , Takahashi Ryuhei
Published: February 2006

To improve the resolution in the downrange direction in radar cross section (RCS) measurements, the frequency bandwidth must be widened. Therefore, to measure the RCS at high resolution in a limited frequency bandwidth, we proposed a technique that applies the multiple signal classification (MUSIC) algorithm and obtains the profile in the downrange direction. However, an experimental evaluation still has not been conducted in an outdoor RCS test range of an actual electromagnetic wave propagation environment. In this paper, we evaluated this method by positioning two cylindrical or cubic measurement targets as scatterers of radio waves in the downrange direction and conducted RCS measurements outdoors. The results verified an improvement in the downrange resolution of about threefold compared to a conventional Fourier transform and the effectiveness of this measurement method. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(6): 23–31, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20272
Radiation characteristics of a transmission line with a side plate
Authors: Nakamura Takashi , Takase Naoya , Sato Risaburo
Published: February 2006

As a structure that reduces radiation from a transmission line with input and output ports, a transmission line with a side plate is proposed in this paper. The radiation field by the traveling wave current on the transmission line is derived and the radiated power is analytically derived. From this analysis, it is found that in order to reduce radiation loss, (1) the transmission line height should be reduced, (2) the characteristic impedance be increased, (3) the propagation constant of the current be increased, and (4) the distance to the side plate be reduced. Further, a transmission line with a side plate is fabricated and the effect of radiation reduction is compared with the theoretical result and demonstrates the validity of the paper. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(6): 1–10, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20274
Single integral expression of impedance between arbitrary placed bent rectangle dipoles in moment method using surface elements
Authors: Yoshikawa Yukihiro , Miyashita Hiroaki , Makino Sigeru
Published: February 2006

One of the analysis methods of moment for antennas and scatterers composed of perfect conductors is the subdomain Galerkin's method, in which the surface currents are expanded piecewisely and the expansion and the weighting functions are the same. In comparison with the point matching method, the subdomain Galerkin's method can obtain accurate results with fewer segment partitions. However, it is necessary to perform fourfold integrations in the calculations of the impedance matrix elements. In the present paper, it is shown that the fourfold integrations of the impedance matrix elements between arbitrarily placed bent rectangular dipole segments can be reduced to single integral expressions. The validity of the proposed method is verified by comparison with the numerical results of fourfold integrations. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(6): 11–22, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20276
Application of improved PSO to power flow control by TCSC for maximum acceptance of requested wheeled power
Authors: Hayashi Yasuhiro , Matsuki Junya , Kanai Genshin
Published: February 2006

Open access to electric power transmission networks has been carried out in order to foster generation competition and customer choice worldwide. When several PPSs request to simultaneously supply power to customers based on bilateral contracts, it is expected that the transmission network accepts amounts of wheeled power requested by the PPSs as much as possible. It is possible to maximize total requested wheeled power by controlling power flow through transmission lines. It is well known that FACTS device is available to control line flow flexibly. In this paper, in order to maximize total wheeled power simultaneously requested by several PPSs, the authors propose an algorithm to determine the optimal reactance of TCSC (a type of FACTS device). The proposed algorithm is based on Particle Swarm Optimization (PSO), which is an optimization method based on swarm intelligence. In the proposed algorithm, PSO is improved to enhance ability of searching global minimum by giving different characteristic to behavior of each agent. In order to check the validity of the proposed method, numerical results are shown for 6 and IEEE 30 bus system models. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 17–26, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20085
Drift velocity of electron swarm in configuration space
Authors: Takeda Akihide , Ikuta Nobuaki
Published: February 2006

In 1977, Tagashira and colleagues reported that the center‐of‐mass drift velocity Wr of an electron swarm defined in time of flight (TOF) takes a larger value than the drift velocity Wv defined in pulsed Townsend (PT) when ionization collisions take place. At the same time, they explained that the larger values of Wr are caused by the ionization generation of electrons at the front side of extending swarm due to higher mean energy. In this paper, a new definition of virtual drift velocity in configuration space W′r defined in PT is proposed, and calculated data of drift velocities and related quantities such as ionization coefficients and ionization frequencies in Ar in a high E/N range are discussed relative to Tagashira's data. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 1–7, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20131
Investigation of topology optimization of magnetic circuit using density method
Authors: Okamoto Yoshifumi , Takahashi Norio
Published: February 2006

Topology optimization using the density method, which determines the optimal topology by distributing the magnetic material in the design domain, is attractive for designers of magnetic devices, because an initial conceptual design can be obtained. As the number of design variables in the design domain is so huge, a sufficient solution cannot be obtained by using the direct search method. Then, the steepest descent method is adopted to obtain fast convergence. In this paper, some problems in applying the density method to the practical topology optimization are investigated. The accuracy of calculating the sensitivity using the adjoint variable method and the effect of initial material density on the obtained results are examined. The effectiveness of the proposed optimization method is illustrated by applying it to the determination of the optimal topology of a permanent magnet which generates a uniform magnetic field. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 53–63, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20259
Finite‐dimensional approximate modeling with error bounds of flexible vibrating systems based on partial eigenstructures
Authors: Imai Jun , Wada Kiyoshi
Published: February 2006

An approach to control‐oriented uncertainty modeling is presented for a class of elastic vibrating systems such as flexible structures, beams and strings, described by partial differential equations. Uncertainty bounding techniques are developed using the upper and lower bounds of the unknown eigenparameters. The result forms a basis for a finite‐dimensional controller design in which closed loop stability and performance are guaranteed. A feasible set of systems is defined of all systems governed by a class of differential equations with certain norm bounds of the unknown input and output operators and with partially known bounds of the eigenparameters. Then the perturbation magnitude covering the feasible set is evaluated in the frequency domain where a standard truncated modal model is chosen as the nominal one. An upper bound to the truncated error magnitude which is calculated by linear programming is proposed. It is demonstrated that all the parameters formulating a feasible set are derived by finite element analysis for a flexible beam example, and feasibility of the proposed scheme is also illustrated by numerical bounding results. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 36–44, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20272
Development of diode‐pumped solid‐state laser HALNA for fusion reactor driver
Authors: Kawashima Toshiyuki , Kanabe Tadashi , Matsumoto Osamu , Yasuhara Ryo , Furukawa Hiroyuki , Miyamoto Masahiro , Sekine Takashi , Kurita Takashi , Kan Hirofumi , Yamanaka Masanobu , Nakatsuka Masahiro , Izawa Yasukazu
Published: February 2006

The diode‐pumped slab laser for inertial fusion energy driver has been demonstrated, which produces the 1053‐nm output energy of 10 J at 10 Hz. The glass slab laser amplifier has been pumped by quasi‐CW 290‐kW AlGaAs laser‐diode arrays at 803 nm. The optical system can compensate for thermal effects by use of zigzag optical propagation, image‐relayed telescope, and 45° Faraday rotator. The output energy of 10.6 J at 1 Hz with the optical‐to‐optical conversion efficiency of 19.9% has been successfully obtained. Also, the 10‐Hz operation has been performed with an output energy of 5.1 J. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 27–35, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20288
Characteristic of an AC chopper circuit with LC filters in the input and output side
Authors: Shinyama Takayuki , Kawai Makoto , Torii Akihiro , Ueda Akiteru
Published: February 2006

LC filters are connected to both the input and output side of the AC chopper circuit in order to remove the switching ripple and harmonics. Characteristics of THD and input power factor are examined by simulation and experiments. When the load is resistive, characteristics are minimally influenced by the filters. In the case of an inductive load, since two poles exist owing to the input and output filters, waveform distortion becomes large. This paper shows that THD can be improved by reducing input filter capacitance. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 45–52, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20304
Tuning of the Spin States in Trinuclear Cobalt Compounds of Pyridazine by the Second Simple Bridging Ligand
Authors: Yi Tao , Ho‐Chol Chang , Gao Song , Kitagawa Susumu
Published: February 2006

Three novel trinuclear cobalt(II) compounds of pyridazine,[Co3(μ‐OH)2(μ‐pdz)4(pdz)2(NO3)2(H2O)2]·(NO3)2·(THF)·2(MeOH) (1), [Co3(μ‐OH)2(μ‐pdz)4(pdz)4(NO3)2]·[Co3(μ‐OH)2(μ‐pdz)4(MeOH)4(NO3)2]·(NO3)4 (2), and [Co3(μ‐pdz)4(μ‐NCS)2(pdz)2(NCS)4]·2MeOH (3) (pdz = pyridazine), have been synthesized and characterized. The structures of all three compounds consist of centrosymmetric trimer building blocks bridged by the two nitrogen atoms of the pyridazine ligands and the second small bridging anions (hydroxide in 1 and 2, and end‐on thiocyanate in 3). The two‐atom bridging modes of the pyridazine ligand in 1 and 2 are unusual: each bridging pyridazine ligand affords two nitrogen donors to two metal ions with different bond lengths. This results in two kinds of spin states for the cobalt(II) atoms in 1. Magnetic measurements show a typical antiferromagnetic interaction between the high‐spin metals in 3, but an unusual magnetic coupling through two high‐ and one low‐spin cobalt atoms within the trimer in 1. An irregular spin states structure is also observed in 1 at low temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Supramolecular Trapping of Phosphanes by Cyclodextrins: A General Approach to Generate Phosphane Coordinatively Unsaturated Organometallic Complexes
Authors: Binkowski‐Machut Cécile , Canipelle Michaël , Bricout Hervé , Tilloy Sébastien , Hapiot Frédéric , Monflier Eric
Published: February 2006

As shown by 31P{1H} NMR spectroscopy, addition of the native β‐cyclodextrin or randomly methylated β‐cyclodextrin to an aqueous solution of Cl[Pt{(p‐tBuC6H4)P(m‐C6H4SO3Na)2}3Cl] or [Pd{(p‐tBuC6H4)P(m‐C6H4SO3Na)2}3] allows us to generate the phosphane coordinatively unsaturated [Pt{(p‐tBuC6H4)P(m‐C6H4SO3Na)2}2Cl2] or [Pd{(p‐tBuC6H4)P(m‐C6H4SO3Na)2}2] complexes, respectively. The existence of second‐sphere coordination adducts between the organometallic complex and the cyclodextrin, in which the local bulkiness around the metallic centre is high, appears to be the essential prerequisite for the dissociation of one (p‐tBuC6H4)P(m‐C6H4SO3Na)2 phosphane ligand from the metal centre. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Radical‐Radical and Metal–Metal Coupling Tetrathiafulvalene Derivative in which Organic Radicals Directly Coordinate to CuII Ions
Authors: Lu Wen , Zhang Yong , Dai Jie , Zhu Qin‐Yu , Bian Guo‐Qing , Zhang De‐Qing
Published: February 2006

A new dinuclear metal complex including tetrathiafulvalene (TTF) radicals as ligands has been prepared and characterized, [{DMT‐TTF(CONH2)2}2Cu2Cl6] (1), DMT‐TTF(CONH2)2 = o‐bis(amido)‐appended dimethylthio‐tetrathiafulvalene. The compound is an uncommon example in which TTF radicals directly coordinate to the copper(II) halide by the amido group. Crystal structure analysis shows that it is a unique coordination bond/H‐bond/S···S stacking cooperative system with two radicals and two paramagnetic transition metal ions, TTF+·–CuII–CuII–TTF+·. In the structure of 1, the DMT‐TTF units form dimers with very strong S···S interactions. The CuII–O(amide) distance of the coordination bond is 2.271(2) Å and the S···S stacking distances between the radicals are in the range 3.345–3.489 Å. The metal–metal ions are mildly antiferromagnetically coupled (2J1 =–58.4 cm–1), while the radical pairs are strongly antiferromagnetically coupled (2J2 > –1000 cm–1).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Zinc Thiolate Complexes [ZnLn(SR)]+ with Azamacrocyclic Ligands: Synthesis and Structural Properties
Authors: Notni Johannes , Görls Helmar , Anders Ernst
Published: February 2006

A series of 24 novel zinc thiolate complexes containing saturated macrocyclic polyamine ligands with the general formula [Zn(Ln)(SR)]ClO4 (Ln: n‐dentate azamacrocyclic ligand) has been synthesized. Two different thiolate ligands (R = phenyl, benzyl) and 12 macrocyclic ligands with ring sizes varying from 11 to 16 atoms and containing three, four, and five nitrogen donors (including a new macrocyclic triamine ligand, 8‐methyl‐[11]aneN3) have been used. The solid‐state structures of 20 of the 24 complexes have been characterized by X‐ray diffraction. The crystal lattice of all compounds is comprised exclusively of monomers. The tetracoordinate N3S compounds exhibit Zn–S bond lengths ranging from 2.2259(5) to 2.2492(9) Å and the pentacoordinate N4S systems from 2.266(2) to 2.3200(7) Å. In addition, two complexes with the very rare N5S coordination environment for zinc have been found. They exhibit Zn–S bond lengths of 2.3782(7) and 2.42 Å (mean value of two independent molecules). The thiolate complexes are suitable model systems for the precursor proteins of matrix metalloproteases (pro‐MMPs) as well as for thiolate alkylating enzymes such as cobalamine‐dependent/independent methionine synthases, farnesyl transferase, and the Ada repair protein. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Dipolar Organoiron Pyranylideneacetaldehyde Hydrazone Complexes: Synthesis, Characterization, Crystal Structure, Linear and Nonlinear Optical Properties
Authors: Millán Lorena , Fuentealba Mauricio , Manzur Carolina , Carrillo David , Faux Nadège , Caro Bertrand , Robin‐Le Guen Françoise , Sinbandhit Sourisak , Ledoux‐Rak Isabelle , Hamon Jean‐René
Published: February 2006

New cationic organoiron(II) pyranylideneacetaldehyde hydrazone complexes were prepared in high yields through condensation reactions of the organometallic hydrazine precursor [CpFe(η6‐p‐MeC6H4NHNH2)]+PF6– with differently substituted α‐ and γ‐pyranylideneacetaldehydes. The mononuclear hydrazones were stereoselectively obtained as their (E) isomers about the N=C double bond. All the new compounds were thoroughly characterized by a combination of elemental analysis and spectroscopic techniques (1H and 13C NMR, IR, and UV/Vis), and by a single‐crystal X‐ray diffraction analysis of the 2‐tBu‐chromene derivative 5. The spectroscopic data suggest that these complexes have a partial pyrylium character due to the electron‐accepting ability of the cationic organometallic fragment and to the electron‐releasing properties of the methylenepyran‐based donor. The crystal structure of 5 shows that the η6‐coordinated tolyl ring and the pyran ring are coplanar (dihedral angle 3.2°), a favorable situation that allows conjugation between the intracyclic oxygen atom and the cationic iron center through the entire hydrazone backbone. Compounds 4–6 are strongly polarized D–π–A systems that exhibit solvatochromic properties, low‐lying intramolecular charge‐transfer bands in their electronic absorption spectra, and enhanced second‐order NLO properties (μβ), as measured by the EFISH technique at 1.907 μm. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis of η2‐Allene Complexes by the Reaction of a η1‐Vinylidene Tungsten Complex with Diazoalkanes
Authors: Ipaktschi Junes , Rooshenas Parham , Dülmer Ansgar
Published: February 2006

The reaction of the η1‐vinylidene complex Cp(CO)(NO)W=C=CH2 (5) with diazomethane, to give complex 8, as well as with ethyl diazoacetate, to give complexes 10 and 11, is described. The crystal structures of these complexes are reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Facile Synthesis of SnO2 Hollow Nanospheres and Applications in Gas Sensors and Electrocatalysts
Authors: Zhao Qingrui , Gao Yang , Bai Xue , Wu Changzheng , Xie Yi
Published: February 2006

Tin oxide (SnO2) hollow nanospheres have been successfully synthesized from mixed ethanol and water systems containing the surfactants sodium dodecyl benzenesulfonate (SDBS) and terephthalic acid. Systematic studies reveal that terephthalic acid plays pivotal roles in the formation of hollow nanospheres. In the present work, the as‐synthesized SnO2 hollow nanospheres exhibit excellent room‐temperature ethanol sensitivity and potential catalytic ability towards the electrooxidation of ethanol, and thus are expected to be economical alternative catalysts and useful in industrial applications such as room‐temperature gas sensors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Reactivity of [Ru(Cp*)(L)(MeCN)2][PF6] (L = Ph2POMe or Ph2P‐o‐tolyl) and {Ru(Cp*)[Ph2PCH2C(tBu)=O](MeCN)}[PF6] Complexes, Their Involvement as Catalyst Precursors for Regioselective Allylic Substitution Reactions and Related [Ru(Cp*)Cl(Ph2POMe)(RCHCHCH2)][PF6] η3‐Allyl Ruthenium(IV) Intermediates
Authors: Demerseman Bernard , Renaud Jean‐Luc , Toupet Loïc , Hubert Claudie , Bruneau Christian
Published: February 2006

The synthesis of the new complexes [Ru(Cp*)(L)(MeCN)2][PF6] (L = Ph2POMe or Ph2P‐o‐tolyl) and {Ru(Cp*)[Ph2PCH2C(tBu)=O](MeCN)}[PF6] (2a–c) is achieved starting from [Ru(Cp*)(MeCN)3][PF6]. The acetonitrile ligands in complexes 2a–c are labile, as emphasised by the easy formation of {Ru(Cp*)(CO)2[Ph2PCH2C(=O)tBu]}[PF6] (3). The keto‐phosphane is used as a tool to convert 3 into {Ru(Cp*)(CO)[Ph2PCH2C(tBu)=O]}[PF6] (5). Complex 5 reacts with 1,1‐diphenyl‐2‐propyn‐1‐ol in methanol as solvent toafford the vinyl‐carbene complex {Ru(Cp*)(CO)[=C(OMe)CH=CPh2][Ph2PCH2C(=O)tBu]}[PF6]. The new η3‐allyl ruthenium(IV) derivatives [Ru(Cp*)Cl(Ph2POMe)(CH2CMeCH2)][PF6] and [Ru(Cp*)Cl(Ph2POMe)(RCHCHCH2)][PF6] (R = Me; nPr, 8d; or Ph, 8e) are obtained by reacting 2a with the appropriate allylic halide. The X‐ray crystal structure determination of the compounds 8d and 8e disclosed an endo‐trans‐RCHCHCH2 η3‐allyl ligand. The formation of branched allyl aryl ethers is regioselectively favoured when complexes 2a–c are involved as catalyst precursors for the etherification of cinnamyl chloride, chlorohexene and 3‐chloro‐4‐phenylbut‐1‐ene with phenol, p‐methoxyphenol, cresols and (o or p)‐chlorophenols, in the presence of K2CO3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Decameric Water Clusters Shaped as Two Parallel Cyclic Pentamers with Staggered Conformation Stabilize Supramolecularly Bonded Infinite Chains of H2PO4– Ions
Authors: Ghosh Sujit K. , Bharadwaj Parimal K.
Published: February 2006

A laterally nonsymmetric aza‐cryptand on acidification with H3PO4 affords an H‐bonded infinite chain of H2PO4– ions. These chains are aligned parallel through H‐bonding interactions with discreet decameric water clusters leaving large void spaces. Diprotonated cryptand molecules occupy these voids through supramolecular interactions. The crystal data for the compound are: triclinic space group P$\bar {1}$, a = 12.765(5), b = 13.254(2), c = 13.817(4) Å, V = 2137.3(14) Å3, Z = 2, R1 = 0.0582, wR2 = 0.1339, S = 1.092.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Photoinduced Phase Transition of the Coordinationally Unsaturated d9 Metal Centers of Bis(N,N‐diethylethylenediamine)copper(II) Perchlorate within the Thermal Hysteresis of the Spin‐Exchange Interaction
Authors: Naumov Panče , Sakurai Kenji , Asaka Toru , Belik Alexei A. , Adachi Shin‐ichi , Takahashi Junichi , Koshihara Shin‐ya
Published: February 2006

Diffraction evidence is presented that the structure of one‐dimensional arrays of strained, coordinationally unsaturated d9 pseudo‐Jahn–Teller centers of bis(N,N‐diethylethylenediamine)copper(II) perchlorate is affected by excitation of the LMCT bands within the hysteresis region of a low‐temperature ferromagnetic‐to‐antiferromagnetic phase transition. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Enolate‐Phosphane Ligands Providing a Tool for the Selective Substitution of Triphenylphosphane by Carbon Monoxide or Trimethylphosphane in Complex {Ru(Cp)[η2‐P,O‐Ph2PCH2C(tBu)=O](PPh3)}[PF6], and Subsequent Reactivity Towards Terminal Alkynes
Authors: Demerseman Bernard , Toupet Loïc
Published: February 2006

The deprotonation under basic conditions of the keto‐phosphane ligand in complexes {Ru(Cp)[η1‐P‐Ph2PCH2C(=O)tBu](PPh3)(L)}[PF6] (L = CO or PMe3) that arise from the addition of L to {Ru(Cp)[η2‐P,O‐Ph2PCH2C(tBu)=O](PPh3)}[PF6] generates {Ru+(Cp)[η1‐P‐Ph2PCH=C(tBu)O–](PPh3)(L)} zwitterionic species, as shown by an X‐ray crystal structure determination (L = CO). The removal of the triphenylphosphane ligand is subsequently achieved under thermal activation to afford the neutral derivatives Ru(Cp)[η2‐P,O‐Ph2PCH=C(tBu)O](L). A further protonation step is sufficient to complete the formation of the new complex {Ru(Cp)[η2‐P,O‐Ph2PCH2C(tBu)=O](PMe3)}[PF6], which reacts in methanolat reflux with 1,1‐diphenyl‐2‐propyn‐1‐ol to afford thesix‐membered metallacyclic derivative {Ru(Cp)[η2‐C,P:C(CH=CPh2)OC(tBu)=CH–PPh2](PMe3)}[PF6], as shown by an X‐ray single crystal analysis. The synthesis of related η5‐indenyl ruthenium complexes and of {Ru(Cp)(=C=CH2)[Ph2PCH2C(=O)tBu](PR3)}[PF6] (PR3 = PPh3 or PMe3) vinylidene complexes is also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Surface bloom on improperly tempered chocolate
Authors: Lonchampt Pierre , Hartel Richard W.
Published: February 2006

The surface composition, in terms of sugar and fat content, on untempered and over‐tempered chocolates was estimated by carefully scraping the surface layer and analyzing fat and sugar melting enthalpies by differential scanning calorimetry. The dull surface of over‐tempered chocolate had a fat and sugar composition similar to the initial chocolate mass, whereas the surface bloom formed on untempered chocolate was nearly depleted of fat, containing primarily sugar and cocoa solids. This was confirmed qualitatively by using polarized light microscopy, where no fat crystals could be observed in the bloom spots. Bloom on untempered chocolate corresponded to a phase separation between fat, sugar and cocoa solids. In contrast, the grey, dull aspect of the surface of over‐tempered chocolate had essentially the same sugar‐to‐fat ratio as the intact chocolate and was due to a diffuse reflection of light on a rough surface, most likely induced by large cocoa butter crystals. Bloom on untempered chocolate developed regardless of the relative humidity of storage (between 0 and 75%). However, bloom developed more quickly and to a greater extent at lower relative humidity. Whiteness was directly related to the number, diameter and growth speed of the white bloom spots.
Diversity Linker Units for Solid‐Phase Organic Synthesis
Authors: Scott Peter J. H. , Steel Patrick G.
Published: February 2006

In recent years an ever‐increasing number of traditional solution‐phase reactions have been adapted for solid‐phase organic synthesis (SPOS) because of the ease of application of solid‐phase techniques to combinatorial chemistry and high‐throughput screening. To accommodate the growing number of reactions being attempted on solid supports, new linker units continue to be reported in the literature. Linker units are typically grouped according to the functionality left at the “cleavage site” in the target molecule, and are normally classified as traditional (polar functionality remains following cleavage) or traceless (hydrogen residue left after cleavage) linkers. As the field continues to expand, however, more advanced linker units have been reported, which utilise the cleavage step in SPOS to incorporate additional diversity into target libraries. These linker units have been termed “diversity” or “multifunctional” linker units, and in this microreview we introduce this aspect of the field, giving representative examples indicating key stages of development including the linker units recently designed in our laboratory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Enantiospecific Synthesis of (+)‐Hyacinthacine A2
Authors: Dewi‐Wülfing Purnama , Blechert Siegfried
Published: February 2006

We report an efficient synthesis of (+)‐hyacinthacine A2 in six steps from (S)‐N‐Cbz‐vinylgylcine. The key strategies were the olefin cross metathesis (CM), Sharpless asymmetric dihydroxylation, and a sequential double reductive cyclization. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Testing excision models for responses of mismatch‐repair systems to UV photoproducts in DNA
Authors: Wang Huxian , Hoffman Peter D. , Lawrence Christopher , Hays John B.
Published: February 2006

Mismatch‐repair (MMR) systems correct DNA replication errors and respond to a variety of DNA lesions. Previous observations that MMR antagonizes UV mutagenesis, and that the mismatch‐recognition protein heterodimer MSH2•MSH6 (MutSα) selectively binds DNA containing “mismatched” photoproducts (T[CPD]T/AG, T[6‐4]T/AG) but not “matched” photoproducts (T[CPD]T/AA, T[6‐4]T/AA), suggested that mismatched photoproducts would provoke MMR excision similar to mismatched bases. Excision of incorrect nucleotides inserted opposite template photoproducts might then prevent UV‐induced mutation. We tested T[CPD]T/AG DNA, in a sequence context in which it is bound substantially by hMutSα and in three other contexts, for stimulation of 3′ MMR excision in mammalian nuclear extracts. T[CPD]T/AG was inactive in HeLa extracts, or in extracts deficient in the photoproduct‐binding proteins DDB or XPC• hHR23B, arguing against interference from the nucleotide excision repair pathway. Prior incubation with hMutSα and MLH2·PMS2 (hMutLα) did not increase excision relative to homoduplex controls. T[6‐4]T/AG also failed to provoke excision. T/G, C/A, and T/T substrates, even though bound by hMutSα no better than T[CPD]T/AG substrates, efficiently provoked excision. Even a substrate containing three T[CPD]T/AG photoproducts (in different contexts) did not significantly provoke excision. Thus, MMR may suppress UV mutagenesis by non‐excisive mechanisms. Environ. Mol. Mutagen., 2006. © 2006 Wiley‐Liss, Inc.
Identification of candidates for tumor‐specific alternative splicing in the thyroid
Authors: Guimarães Gustavo S. , Latini Flávia R. M. , Camacho Cléber P. , Maciel Rui M. B. , Dias‐Neto Emmanuel , Cerutti Janete M.
Published: February 2006

Alternative splicing is the differential processing of exon junctions to produce a new transcript variant from one gene. Some aberrant splicing, however, has been shown to be cancer specific. Identification of these specific splice variations will provide important insight into the molecular mechanism of normal cellular physiology as well as the disease processes. To gain knowledge about whether alternative splicing is linked to thyroid tumorigenesis, we used our prediction database to select targets for analysis. Fifteen putatively new alternative splicing isoforms were selected on the basis of their expression in thyroid libraries and/or their origin in genes previously associated with carcinogenesis. Using a set of 66 normal, benign, and malignant thyroid tissue samples, new splicing events were confirmed by RT‐PCR for 13 of 15 genes (a validation rate of 87%). In addition, new alternative splicing isoforms not predicted by the system and not previously described in public databases were identified. Five genes (PTPN18, ABI3BP, PFDN5, SULF2, and ST5) presented new and/or additional unpredicted isoforms differentially expressed between malignant and benign or normal thyroid tissues, confirmed by sequencing. PTPN18, ABI3BP, and PFDN5 revealed a statistically significant differential splicing profile. In addition, real‐time PCR analysis revealed that expression of an alternative PFDN5 variant was higher in malignant lesions than in benign lesions or normal tissues. © 2006 Wiley‐Liss, Inc.
Enzymatic Approach to and Odor Description of the Twelve Enantiomerically Pure Isomers of Pelargene®
Authors: Abate Agnese , Allievi Maurizio , Brenna Elisabetta , Fuganti Claudio , Gatti Francesco G. , Serra Stefano
Published: February 2006

Pelargene® is a commercial fragrance sold as a mixture of three regioisomeric pyran derivatives (1–3). The enantiomers of each of the two possible diastereoisomers of 1–3 were prepared by means of a biocatalyzed approach, and the odor properties of the twelve isolated stereoisomers were evaluated.
Structure Investigation of Bridgehead Aziridine: Synthesis, Theoretical, and Crystallographic Study of 2,4,6‐Triphenyl‐1,3‐diazabicyclo[3.1.0]hex‐3‐ene
Authors: Bruno Giuseppe , Nicolò Francesco , Rotondo Archimede , Risitano Francesco , Grassi Giovanni , Foti Francesco
Published: February 2006

A one‐pot three‐component procedure to efficiently create the 1,3‐diazabicyclo[3.1.0]hex‐3‐ene system is reported. The molecular structure of 2,4,6‐triphenyl‐1,3‐diazabicyclo[3.1.0]hex‐3‐ene (3) was studied by X‐ray diffraction and compared to ab initio and density‐functional‐theory (DFT) calculations restricted to the core moiety. Geometry optimizations for structural isomers and tautomeric forms of this aziridine fragment, taken as simplified models, were carried out at high calculation levels. Moreover, the same methods were utilized to evaluate the proton affinity of two crucial aziridine tautomers.
Novel Steroidal Glycosides from two Indian Caralluma species, C. stalagmifera and C. indica
Authors: Kunert Olaf , Rao Belvotagi Venkatrao Adavi , Babu Gummadi Sridhar , Padmavathi Medaboyina , Kumar Bobbala Ravi , Alex Robert Michael , Schühly Wolfgang , Simic Nebojsa , Kühnelt Doris , Rao Achanta Venkata Narasimha Appa
Published: February 2006

New steroidal glycosides, stalagmosides I–V (1–5) and indicosides I and II (7 and 8), together with the known compounds carumbelloside III, lasianthoside A, and lasianthoside B, were isolated from whole plants of Caralluma stalagmifera and Caralluma indica, respectively. Their structures were elucidated by extensive NMR spectroscopic studies.
Norditerpenoid Alkaloids from the Aerial Parts of Aconitum cochleareWoroschin
Authors: Meriçli Ali H. , Pırıldar Sevda , Süzgeç Sevda , Bitiş Leyla , Meriçli Filiz , Özçelik Hasan , Zapp Josef , Becker Hans
Published: February 2006

From the aerial parts of Aconitum cochleare Woroschin, two new norditerpenoid alkaloids named aconitilearine (1) and N‐deethylmethyllycaconitine (2) were isolated along with the eight known norditerpenoid alkaloids 3–10. The structures for the new compounds were established on the basis of 1H, 13C, DEPT, homonuclear 1H,1H‐COSY, NOESY, HSQC, and HMBC NMR studies.
Total Synthesis of (+)‐β‐Himachalene
Authors: Ho Tse‐Lok , Chein Rong‐Jie
Published: February 2006

An enantioselective synthesis of (+)‐β‐himachalene (2) was accomplished starting from (1S,2R)‐1,2‐epoxy‐p‐menth‐8‐ene (3) in 15 or 16 steps with an overall yield of ca. 6% (Schemes 3, 5, and 6). Key transformations include an Ireland–Claisen rearrangement, a Corey oxidative cyclization, and a ring expansion.
Formation of Dimers of Some 2‐Substituted Indan‐1‐one Derivatives during Base‐Mediated Cross‐Aldol Condensation
Authors: Narang Gaurav , Jindal Dharam Paul , Jit Birinder , Bansal Ranju , Potter Brian S. , Palmer Rex A.
Published: February 2006

Unexpected dimers of some 2‐substituted indan‐1‐one derivatives were isolated during aldol condensation of indan‐1‐one with various aldehydes in the presence of KOH (see Scheme). Monomeric products, usually expected from aldol condensation, further underwent a base‐catalyzed nucleophilic addition reaction to their dimeric form in some cases. The structures of these dimers were characterized by using various spectral techniques and in one case, structural details were determined from a high‐resolution crystallographic analysis.
A One‐Dimensional Thallium(I) Coordination Polymer Involving Polyhapto‐Aromatic Interactions
Authors: Askarinejad Azadeh , Morsali Ali
Published: February 2006

A one‐dimensional coordination polymer involving Tl ⋅⋅⋅ C interactions, [Tl(μ4‐dpa)]n(Hdpa = diphenylacetic acid), was synthesized and characterized. The single‐crystal X‐ray data of the compound show that the coordination number of the TlI ions is five and that Tl centers have an irregular coordination sphere containing a ‘configurationally active’ lone pair/hexahapto (η6) interaction, thus resulting in a total hapticity of eleven for a TlC6O5 environment.
An Alternative Synthesis of the Dopaminergic Drug 2‐Amino‐1,2,3,4‐tetrahydronaphthalene‐5,6‐diol (5,6‐ADTN)
Authors: Göksu Süleyman , Seçen Hasan , Sütbeyaz Yaşar
Published: February 2006

Racemic 2‐amino‐1,2,3,4‐tetrahydronaphthalene‐5,6‐diol (5,6‐ADTN; 4) was synthesized from 5,6‐dimethoxynaphthalene‐2‐carboxylic acid (14) in four steps (60% overall yield; Scheme). The crucial steps of the synthesis are Birch reduction of 14 to the valuable synthon 15, Curtius reaction and carbamate formation (16), hydrogenolysis (17), and demethylation to the biologically active hydrobromide salt 18 of 4.