bluuebunny/crossref_metadata_2025 huggingface dataset:
Light propagation in a coupled waveguide‐triple quantum well structure
Authors: Yamaguchi M. , Yokoi M. , Sawaki N.
Published: May 2008

The light propagation in a waveguide which was weakly coupled to a quantum well (QW) structure was studied to demonstrate the detectability of the electronic states in the small area of QW. The small area of QW was made with a GaAs/AlGaAs asymmetric triple QW. Since the electronic states in the triple QW were easily controlled by an electric field which was induced by an optical injection, we observed the optical spectra obtained from the waveguide under the various intensities of optical injection. The spectral change was observed around the characteristic wavelengths of the QW. In order to verify the observed spectral change, we measured the optical spectra of the traveling wave in a sample whose QW surface has been etched off. By comparing the results, we interpreted that the spectral change is due to the reconstruction of the electronic states in the small area of QW due to the optically excited carriers. This proves the detection of small electronic state changes in the small area of QW with the traveling light in the waveguide. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vertically scaled 80‐nm‐gate InP‐based HEMTs with a cutoff frequency of 450 GHz
Authors: Hara Naoki , Takahashi Tsuyoshi , Ohki Toshihiro , Makiyama Kozo
Published: May 2008

We have successfully fabricated vertically scaled 80‐nm‐gate InP‐based HEMTs with fully SiN passivated gate‐recess regions and achieved high cutoff frequency of 450 GHz. By reducing gate‐recess length to 50 nm, high performance was realized even with a rather long gate length of 80 nm. We also employed a fully passivated gate‐recess structure, which is essential for obtaining thermally stable devices. Au interconnections with benzocyclobutene as an interlayer dielectric film were formed on this device and no change in DC characteristics was observed. These results indicate that the device reported in this paper is promising for integrated circuits used in millimeter‐wave applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First principles study of the decomposition processes of AlN in a hydrogen atmosphere
Authors: Panyukova U. , Suzuki H. , Togashi R. , Murakami H. , Kumagai Y. , Koukitu A.
Published: May 2008

The growth of AlN films by the hydrogen vapor phase epitaxy method is generally carried out at a high temperature over a hydrogen atmosphere. The difficulties concerned with the decomposition processes on the surface during the film growth result in necessity of computer modelling of that processes. First principles calculations of the decomposition processes of AlN in a hydrogen atmosphere are reported. The mechanism of desorption of atoms from the surface was determined. Al atoms desorb as AlH from (0001) surface and as Al from (000‐1) surface of AlN. And N atoms desorb as NH3 from (0001) surface and as NH from (000‐1) surface of AlN. The desorption of Al atoms is a rate limiting reaction. The calculation results correspond well with the experimental date published earlier. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Refractive index of TlGaAs
Authors: Ohnishi K. , Shiba M. , Yamakage M. , Kajikawa Y.
Published: May 2008

Refractive index has been determined from reflectance measurements at 77‐300 K for Tlx Ga1–x As samples with x ≤ 0.077 prepared by low‐temperature molecular‐beam epitaxy. A very high refractive index of around 4.5 at room temperature in the transparent wavelength region has been revealed for Tlx Ga1–x As with x = 0.077. The temperature coefficient of the refractive index was found to increase with Tl content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN‐ and AlGaN‐based UV‐LEDs on sapphire by metal‐organic chemical vapor deposition
Authors: Okimoto T. , Tsukihara M. , Kataoka K. , Kato A. , Nishino K. , Naoi Y. , Sakai S.
Published: May 2008

We investigated the relationship between the dislocation densities and the electro‐luminescence (EL) peak intensities in AlGaN, which was grown on GaN‐ or AlGaN‐on sapphire, by low‐pressure metalorganic chemical vapor deposition. Crystallographic properties of the AlGaN epilayer has been investigated by a high‐resolution X‐ray diffraction method. We showed that EL intensity was strongly dependent on the full‐width at half maximum (FWHM) from (10$ \bar 1 $2) AlGaN diffraction peaks for GaN‐ or AlGaN‐ based LEDs at omega mode. This result indicated the reduction of edge and mixed dislocation densities led to improvement of the EL characteristics. Although the GaN‐based LEDs absorb UV‐light, the EL intensity was higher than that AlGaN‐based LEDs. Comparing at the same FWHM value of AlGaN (10$ \bar 1 $2) peaks, EL intensity of AlGaN‐based LEDs were several times higher than that of GaN‐based LEDs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polarized laser oscillation from polygon crystals of thiophene/phenylene co‐oligomers grown by liquid‐phase growth
Authors: Yamao Takeshi , Yamamoto Kazunori , Miki Tomoharu , Akagami Hiroshi , Nishimoto Yoshihiro , Hotta Shu
Published: May 2008

We have investigated the laser oscillation and its polarization feature of a thin polygon crystal of a thiophene/phenylene co‐oligomer grown by the novel liquid‐phase method. The emission spectrum from the crystal ca ‐plane (along the b‐axis) narrows with increasing energy of the pulsed laser excitation, which is incident perpendicularly to the crystal plane (the ab ‐plane). The multi‐mode laser oscillation was observed around 515 nm with the excitation over 5 mJ/cm2 per pulse. A mode separation and a full width at half maximum of the peak were estimated to be ∼0.2 nm and ∼65–85 pm, respectively. The laser emission was confirmed to be strongly polarized along the c‐axis. Its polarization ratio of the c‐axis to the a‐axis was estimated to be ∼550. This large ratio is due to the upright configuration of the molecular long axis that is almost perpendicular to the ab‐plane. These results indicate that the present polygon thin crystal is suitable for laser device application. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaAs high‐k dielectric metal‐insulator‐semiconductor structure having silicon interface control layer
Authors: Akazawa M. , Hasegawa H.
Published: May 2008

A pinning‐free high‐k dielectric metal‐insulator‐semiconductor (MIS) gate stack was realized on GaAs surfaces by using a Si interface control layer (Si ICL). The MIS structure has a SiNx/Si ICL ultrathin double layer inserted between GaAs and HfO2. Si ICL was grown epitaxially on a Ga‐stabilized GaAs surface by molecular beam epitaxy (MBE). The ultrathin SiNxbuffer film was formed byin situpartial nitridation of Si ICL in the MBE chamber. An X‐ray photoelectron spectroscopy (XPS) analysis indicated that the ultrathin SiNx/Si ICL structure is chemically stable against air‐exposure, preventing the Si ICL/GaAs hetero‐interface from oxidation, although the ultrathin SiNxfilm itself partially turns into SiOxNy. Using this feature, a high‐k MIS capacitor was formed by ex situ deposition of HfO2on the SiOxNy/Si ICL/GaAs structure. The capacitance‐voltage (C‐V) analysis of the high‐k MIS sample after rapid thermal annealing at 500 °C for 30 sec indicated that the MIS interface is completely free from Fermi level pinning with a minimum interface state density below 1011 cm–2eV–1. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantitative imaging of residual strain profile in large diameter GaAs substrates
Authors: Fukuzawa M. , Yamada M.
Published: May 2008

A near‐infrared imaging polariscope (NIRIP) has been developed quantitatively to measure residual strain profiles in large‐diameter GaAs substrates, in which a near‐infrared camera connected to an image‐processing system is used as a 2D multi‐channel sensor and also a collimated light beam is used to illuminate the whole area of substrate, in addition to a pair of computer‐controlled rotating polarizer and analyser. The measurement time is less than 5 minutes for the GaAs substrate with the diameter of 6‐inch, which is drastically reduced in comparison to that of the scanning infrared polariscope (SIRP) using a single channel sensor and a focused light beam. By comparing the residual strain profiles measured in the same substrates with NIRIP and SIRP, it is confirmed that the NIRIP developed here has the sensitivity equivalent to the SIRP. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The substrate orientation dependence of Be doping in molecular layer epitaxy of GaAs
Authors: Ohno Takeo , Oyama Yutaka , Nishizawa Jun‐ichi
Published: May 2008

Be‐doped GaAs epitaxial layers were grown on (100), (111)A, (111)B and (110) GaAs substrates by MLE. In the growth on (111)A GaAs, the incorporation of Be was enhanced significantly when Be(MeCp)2 was introduced after exposure to AsH3 (AA mode) at 277 °C, and consequently Be concentrations up to 8x1019 cm–3 were achieved. It was shown that the concentration of Be on (111)B GaAs substrate was high when exposed to Be(MeCp)2 after exposure to TEG. The relationship between the surface stoichiometry and Be incorporation is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of GaAs1–xBix/GaAs multi‐quantum wells by molecular beam epitaxy
Authors: Tominaga Yoriko , Kinoshita Yusuke , Feng Gan , Oe Kunishige , Yoshimoto Masahiro
Published: May 2008

GaAs1–xBix/GaAs multi‐quantum well (MQW) structures were grown for the first time by molecular beam epitaxy (MBE). Successful growth of MQWs was demonstrated by observing clear satellite peaks in high‐resolution X‐ray diffraction (HR‐XRD) measurements. Photoluminescence (PL) emission at room temperature (RT) was observed from the MQWs. The peak energy of RT PL emitted from GaAs0.948Bi0.052/GaAs MQWs increased with decreasing thickness of the well layer, which implies quantum size effect. The MQW structures were thermally stable even after annealing up to 800 °C, and the PL emission was observed even after annealing up to 600 °C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluation of surface roughness and nanostructure of indium tin oxide (ITO) films by atomic force microscopy
Authors: Kavei G. , Zare Y. , Mohammadi Gheidari A.
Published: May 2008

Indium tin oxide was deposited on a glass (soda lime glass) by radiofrequency sputtering system at different sputtering gas (argon/oxygen 90/10%) pressures (20–34 mTorr) at room temperature. The sputtering rate was affected by the sputtering gas pressure. The optimum sputtering gas pressure was found to be 27 mTorr. The samples at different thicknesses (168, 300, 400, 425, 475, 500 and 630 nm) were deposited on the substrate. Transparency, electrical conductivity and surface roughness of the films were characterized. The samples were annealed at 350, 400 and 450°C to evaluate annealing process effects on the concerned parameters and, therefore, the above‐mentioned measurements were repeated again. The films exhibited reasonable optical transmittance and electrical conductivity and greatly improved after annealing. The characterization was focused on the scanning of the film surfaces before and after annealing, which has a prominent effect on the optical properties of the films. Film surfaces were scanned by scanning probe microscopy in contact atomic force mode. The most consideration was devoted to image analysis. SCANNING 30: 232–239, 2008. © 2008 Wiley Periodicals, Inc.
Cathodoluminescence study of semiconductor oxide micro‐ and nanostructures grown by vapor deposition
Authors: Piqueras J. , Maestre D. , Ortega Y. , Cremades A. , Fernández P.
Published: May 2008

Nano‐ and microstructures of SnO2, In2O3 and ZnO have been grown during thermal treatment of compacted powders under argon flow. Indium‐doped SnO2 tube‐shaped structures with rectangular cross‐section are obtained by adding a fraction of In2O3 to the starting SnO2 powder. In‐rich nanoislands were found to grow on some edges of the tubes. ZnO nanostructures doped with Sn or Eu were grown by adding SnO2 and Eu2O3 powder, respectively, to the ZnO precursor powder. All the samples have been characterized by the emissive and cathodoluminescence (CL) modes of scanning electron microscopy. CL images from SnO2:In and In2O3:Sn tubes and islands show a higher emission from the Sn‐rich structures related to oxygen deficiency. CL of doped ZnO enables to detect the presence of dopant in specific regions or structures. CL appears to be a useful technique to study optical and electronic properties of semiconductor oxide nanostructures. SCANNING 30: 354–357, 2008. © 2008 Wiley Periodicals, Inc.
Mobile anonymity of dynamic groups in vehicular networks
Authors: Xi Yong , Shi Weisong , Schwiebert Loren
Published: May 2008

Vehicular networks are an emerging network to improve safety, efficiency, and convenience of the existing transportation system. In order to preserve privacy in vehicular networks, it is desirable to keep users anonymous. In this paper, we argue that existing approaches, for example, ring singature and anonymous authentication, are susceptible to intersection attack in vehicular networks, resulting in reduced anonymity, even no anonymity. To quantify the achievable anonymity, we first define a graph‐based model called mobile anonymity for a general dynamic environment. We show that under this model, anonymity can be achieved on the system level as long as the constructed anonymity graph is strongly connected. We then extend this model into vehicular networks by applying it to ring signature and anonymous authentication in vehicular networks. We propose two strategies, the random (RND) strategy and the latest‐preferred (LPR) strategy, and evaluate them via simulation using the C3 simulator. The results show that it is promising to apply RND strategy in vehicular networks. Copyright © 2008 John Wiley & Sons, Ltd.
On the security of context‐adaptive information dissemination
Authors: Schoch Elmar , Keppler Moritz , Kargl Frank , Weber Michael
Published: May 2008

Information dissemination rather than traditional routing is useful for many application domains in mobile ad hoc networks. Context‐adaptive information dissemination is a special variant, which was originally designed for vehicular ad hoc networks (VANETs), but could also be used in other domains, for example, disaster management. In this work, we address the security of this dissemination scheme. The attack analysis shows weaknesses but also how the adaption to context already limits the impact of many attacks. We present and evaluate a sensor‐based protection system helping to reduce the margin for attacks to a level of local disturbance, while the overall dissemination is not affected significantly any more. Copyright © 2008 John Wiley & Sons, Ltd.
Local fast re‐authentication for 3G‐WLAN interworking
Authors: Shidhani Ali Al , Leung Victor C. M.
Published: May 2008

Interworking third‐generation (3G) mobile communications systems and wireless local area networks (WLANs) is advantageous for both service providers and end users. However, securing such interworking architectures is a challenging task. EAP‐AKA is the security protocol adopted by 3GPP to achieve authentication in 3G‐WLAN interworking architectures. This paper proposes enhancements to EAP‐AKA to improve performance and security during re‐authentication. A novel protocol named local fast re‐authentication (LFR) is proposed to replace the re‐authentication protocols in EAP‐AKA. The EAP‐AKA key hierarchy is restructured to suit the needs of LFR. Evaluations show that LFR is superior to the re‐authentication protocols in EAP‐AKA in terms of performance and security. LFR has been tested by the automated validation of internet security protocols and applications (AVISPA) security verification tool and proved to be secure.. Copyright © 2008 John Wiley & Sons, Ltd.
Basal levels of salivary chromogranin A, but not α‐amylase, are related to plasma norepinephrine in the morning
Authors: Toda Masahiro , Den Rei , Morimoto Kanehisa
Published: May 2008

To evaluate the activity of sympatho–adrenomedullary (SAM) system, testing for salivary chromogranin A (CgA) and α‐amylase (sAA) has been receiving attention. We investigated the correlation between levels of plasma norepinephrine (NE) and salivary CgA or sAA. From 21 healthy males, blood and saliva samples were collected at 8:00, 10:30, 12:30 and 17:30. Levels of plasma NE, salivary CgA and sAA were determined at each sampling point. To avoid the influence of the salivary flow, resultant levels of salivary CgA and sAA were adjusted according to salivary flow rates and salivary protein, respectively. A significant correlation between plasma NE levels and salivary CgA/protein was detected in samples taken at 8:00 (p < 0.01). In samples taken at 10:30, 12:30 and 17:30, however, there was no such correlation. Meanwhile, no significant correlation between plasma NE levels and sAA/min was detected during the sampling period. These findings suggest that morning results for CgA may be useful as a predictor for SAM system activity. Copyright © 2008 John Wiley & Sons, Ltd.
Erweiterter Einsatz von Turbomolekular Vakuumpumpen durch Beschichtungen
Authors: Froitzheim Michael , Heppekausen Josef
Published: May 2008

Turbomolekular‐Pumpen (TMP) können in einem weiten Druckspektrum zur Förderung der meisten Gase in vielfältiger Applikation eingesetzt werden.

Einschränkungen ergeben sich im Wesentlichen durch die thermische und chemische Belastbarkeit insbesondere des mechanisch hochbeanspruchten Pumprotors.

Möglichkeiten und Grenzen, die Einsetzbarkeit durch funktionale Schichten zu erweitern, werden in diesem Beitrag behandelt.
Kunststoffoptiken mit Antireflex‐ und Antibeschlageigenschaften durch Plasmaätzen und Beschichtung
Authors: Schulz U.
Published: May 2008

Nanostrukturen mit reflexmindernden Eigenschaften können durch Plasmabehandlung auf vielfältigen Polymeren erzeugt werden. Eine noppenartige Struktur mit ausgezeichneten optischen Eigenschaften entsteht auf PMMA völlig selbstorganisierend. Auf vielen anderen Materialien wie Polycarbonat und Zeonex oder auch Polymerlacken kann eine schwammartige Strukturbildung durch das vorherige Abscheiden einer sehr dünnen Schicht initiiert werden. Auch diese Oberflächen erreichen hohe Transmissionswerte und lassen sich besser als die noppenartige Struktur mechanisch stabilisieren. Von großem praktischem Interesse sind außerdem Antibeschlag‐ Eigenschaften, die auf den entspiegelten Oberflächen durch das Aufbringen hydrophiler Oxidschichten erreicht werden.
Vakuumbeschichtung von Architekturglas ‐ Ein historischer Abriss
Authors: Gläser H. J.
Published: May 2008

Beschichtungen auf Architekturverglasungen werden heute überwiegend für Wärme‐ und Sonnenschutz, als Leitschichten in der Photovoltaik sowie in Kombination mit diesen Anwendungen oder getrennt davon zur Entspiegelung, Verspiegelung und für die Selbstreinigung auf Verglasungsaußenoberflächen bei Bewitterung eingesetzt. Hierzu sind Anlagen erforderlich, auf denen Scheiben mit Abmessungen bis zu 3,21m x 6,00m beschichtet werden können. Schichten, mit denen insbesondere Energie eingespart wird, z.B. in Verbindung mit Wärme‐ und Sonnenschutzgläsern oder mit denen Sonnenenergie umgewandelt wird, z.B. in Photovoltaikmodulen, sind von großem wirtschaftlichem Interesse.

Beschichtungstechnologien für die oben genannten Scheibenabmessungen setzen ein hohes Maß an Erfahrungen mit der Physik dünner Schichten voraus. Die wichtigsten Prozesse sind chemische Verfahren bei Atmosphärendruck oder Magnetronsputtern unter Hochvakuum. Der folgende Bericht gibt einen historischen Überblick über die Entwicklung der vakuumbasierten Beschichtungsprozesse für Architekturglas.
ta‐C beschichtete Werkzeuge für die Trockenumformung von Aluminiumblechen
Authors: Weihnacht Volker , Brückner Andreas , Bräunling Sven
Published: May 2008

Anhand von Streifenziehversuchen wurde die Eignung ta‐C beschichteter Werkzeugächen zur Umformung von Aluminiumlegierungen untersucht. Dabei zeigte sich, dass ta‐C, die verschleißfesteste Schichtvariante der diamantartigen Kohlenstoffschichten, auch bezüglich des antiadhäsiven Verhaltens sehr vorteilhaft ist. In Versuchen mit AlMg5Mn‐ sowie Al99Mg1‐Blechen konnten unter Verzicht von Ziehhilfsmitteln mehrere hundert Bleche gezogen werden, ohne dass es zu wesentlichen Aluminium‐Anhaftungen am ta‐ächenqualitäten der gezogenen Bleche verschlechterten sich in dem beobachteten Zeitraum. Im Vergleich zu Versuchen mit unbeschichtetem Werkzeug und Ziehhilfsmitteln schneidet die Variante ta‐C‐trocken nahezu ebenbürtig mit einem guten Ziehhilfsmittel ab.

In einem Praxistest, dem Clinchen von Aluminiumblechen, bestätigten sich die positiven Ergebnisse aus den Streifenziehversuchen. Offenbar ist es möglich, mit ta‐­C beschichteten Clinchstempeln unter völligem Verzicht auf Schmiermittel eine größere Anzahl von Clinchvorgängen durchzuführen, ohne dass es zu merklichen Aluminium‐Anhaftungen am Werkzeug und damit zu einer Erhöhung der Abstreifkräfte kommt.
Evaluierung von Abpumpkurven am Beispiel einer Glimmentladungsquelle
Authors: Klemm Denis , Hoffmann Volker , Edelmann Christian
Published: May 2008

Bei modernen GD‐OES‐Geräten (GD‐OES = Glow Discharge Optical Emission Spectrometry) wird die Analysenzeit (Bruttoanalysezeit: 2 ‐ 5 Minuten) wesentlich durch die Abpumpzeit der Quelle und die Zuverlässigkeit der Spektralanalyse ‐ besonders bei der Analyse dünner Schichten (Schichtdicken < 100 nm) ‐ durch die Gas‐ und Oberflächenreinheit in der Quelle bestimmt.

Bei einem verwendeten kommerziellen Spektrometergerät konnte durch geeignete Dimensionierung und Konstruktion des Pumpsystems und durch optimierte Führung des Flutungs‐ und Abpumpprozesses die Evakuierungszeit und der Enddruck in der Quelle reduziert sowie die Reinheit des Prozessgases am Ort der Analyse verbessert werden.

Eine automatisierte, rechnergestützte Auswertung des zeitlichen Druckverlaufes im Rezipienten wurde entwickelt und gibt dem Anlagenbetreiber Hinweise über mögliche Lecks (z. B. infolge der Abnutzung von Dichtungen) in der Anlage oder über Verunreinigungen innerer Oberflächen, da der zeitliche Druckverlauf durch anlagenspezifische Parameter (u. a. effektives Saugvermögen, Leckrate, Gasabgaberate) bestimmt wird. Mittels Variation dieser Parameter wird die Lösung der Pumpgleichung an die gemessene Druck‐Zeit‐Kurve angepasst. Die dabei gefundenen Parameter sind wichtige Kenngrößen, die den Zustand der Vakuumanlage beschreiben. Damit kann der Anwender rechtzeitig eine Lecksuche durchführen oder Komponenten der Anlage reinigen bzw. ersetzen. Die Kontrolle über den Zustand des Vakuumsystems erhöht die Reproduzierbarkeit der Materialanalyse.
Synthesis and Structural Characterization of Novel Neutral Higher‐Coordinate Silicon(IV) Complexes with SiON3C and SiON4C Skeletons
Authors: González‐García Gerardo , Gutiérrez J. Alfredo , Cota Smaranda , Metz Stefan , Bertermann Rüdiger , Burschka Christian , Tacke Reinhold
Published: May 2008

The neutral pentacoordinate silicon(IV) complex 10 (SiON3C skeleton) and the neutral hexacoordinate silicon(IV) complex 11 (SiON4C skeleton) were synthesized, starting from methyldi(thiocyanato‐N)silane (7). In addition to their monodentate thiocyanato‐N and methyl ligands, these compounds contain a tridentate dianionic O,N,N ligand (10) or a tridentate monoanionic O,N,N ligand (11). Compounds 10 and 11 were characterized by single‐crystal X‐ray diffraction and solid‐state and solution NMR spectroscopy. According to these studies, compounds 10 and 11 exist in solution as well.
Two Sterically Encumbered 1,3,2‐Dioxaphospholanes – Reactions, Comparison of Crystal Structures and Computational Explanations
Authors: Freytag Matthias , Grunenberg Jörg , Jones Peter G. , Schmutzler Reinhard
Published: May 2008

3,4,5,6‐Tetrachlorobenzo‐3‐(2,4,6‐tri‐tert‐butylphenyl)‐1,3,2‐dioxaphospholane (2) and benzo‐3‐(2,4,6‐tri‐tert‐butylphenyl)‐1,3,2‐dioxaphospholane (4), in which the reactive PIII‐center lies close to the sterically demanding Mes* group (Mes* = 2,4,6‐tri‐tert‐butylphenyl), were prepared from Mes*–Br and the corresponding P‐chloro‐phospholane. Compounds 2 and 4 reacted with various oxidants, azides, MeSO3CF3 or [(tht)AuCl] (tht = tetrahydrothiophene) to give the expected products. All crystal structures of the products display a strongly distorted Mes* system with a boat conformation of the phenyl ring and appreciable out‐of‐plane deviations of phosphorus and the ortho‐tert‐butyl groups to opposite sides of the ring. Quantum chemical calculations at the DFT (density functional theory) level of theory were used in order to discriminate between intra‐ and intermolecular forces, which are responsible for these distortions.
Syntheses and Structures of the Germanides CaNiGe and MgCoGe as well as Chemical Bonding in CaNiGe and CaNi2Ge2
Authors: Hlukhyy Viktor , Chumalo Nataliya , Zaremba Vasyl' , Fässler Thomas F
Published: May 2008

The intermetallic germanides CaNiGe and MgCoGe have been synthesized from the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffractions both on powders and single crystals: CeFeSi structure type, P4/nmm, a = 4.19341(3), c = 6.6264(1) Å, wR2 = 0.030, 124 F2 values, 10 variable parameters for CaNiGe and a = 3.8960(4), b = 6.1929(11) Å, wR2 = 0.048, 104 F2 values, 10 variable parameters for MgCoGe. In CaNiGe and MgCoGe the transition metal and germanium atoms build [TGe] layers (T = Ni, Co), which are separated by the calcium and magnesium atoms, respectively. The crystal structures of CaNiGe and MgCoGe as well as chemical bonding in CaNiGe and CaNi2Ge2 are discussed in terms of LMTO bond structure calculation and analysis using the Electron Localization Function (ELF). The Ge–Ge bond formation in polyanionic $^{3}_{\infty}\rm [NiGe]^{-}$ network of CaNi2Ge2 can formally be regarded as oxidative coupling product of $^{2}_{\infty}\rm [NiGe]^{2-}$ layers of CaNiGe.
Das 1,3‐Dimethylcyanurat‐Ion als ambidenter Ligand
Authors: Kuhn Norbert , Abu‐Salem Qutaiba , Maichle‐Mößmer Cäcilia , Steimann Manfred
Published: May 2008

The 1,3‐Dimethylcyanurate Ion as an Ambident Ligand

1,3‐Dimethyl‐2,4,6‐trioxo‐1,3,5‐triazin (7), (1,3‐dimethylcyanuric acid, DMCH), obtained from the thermolysis of methyl urea, is deprotonated with lithium ethylate. In the resulting dinuclear complex [(DMCLi)2·4 H2O] (8), the heterocyclic anions are linked to the lithium centres with oxygen atoms as its enolate form. In the corresponding silver complex [(DMCAg)2·en] (10), (en = ethylendiamine), N‐coordination of the ligand is observed. The crystal structures of 7, 8, and 10 reveal the presence of intermolecular hydrogen bonds.
Sterically Crowded Terphenylselenium Compounds
Authors: Klapötke Thomas M. , Krumm Burkhard , Polborn Kurt
Published: May 2008

Extremely bulky terphenyltriselanes RSeSeSeR with R = 2,6‐(2,4,6‐Me3C6H2)2C6H3 and 2,6‐(2,4,6‐iPr3C6H2)2C6H3 were prepared. The chlorination with sulfuryl chloride resulted in the formation of the corresponding selenenyl chlorides RSeCl. In the case of the methyl substituted derivative, also a chlorination of the mesityl groups was observed and the derivative could be isolated. The molecular structure of the isopropyl substituted triselane [2,6‐(2,4,6‐iPr3C6H2)2C6H3Se]2Se and that of 2,6‐(2,4,6‐Me3C6Cl2)2C6H3SeCl, have been determined by X‐Ray diffraction.
Dimensions of the Ozonide Anion in M([18]crown‐6)O3·x NH3 with M = K (x = 2), Rb (x = 1) and Cs (x = 8)
Authors: Nuss Hanne , Nuss Jürgen , Jansen Martin
Published: May 2008

Reaction of alkali metal ozonides (KO3, RbO3 and CsO3) with [18]crown‐6 in liquid ammonia yields compounds of the composition M([18]crown‐6)O3·x NH3 with M = K (x = 2), Rb (x = 1) and Cs (x = 8). The large intermolecular distance between adjacent radical anions in these compounds leads to almost ideal paramagnetic behavior according to Curie's law. Discrepancies concerning the structure of the ozonide anions in the K and Cs compound compared to a former investigation on Rb([18]crown‐6)O3·NH3 have been resolved by means of DFT calculations and a single‐crystal structure redetermination.
Bridgman Crystal Growth and Structure Refinement of YbPdGe and YbPtGe – Two Different Superstructures of the KHg2 Type
Authors: Katoh Kenichi , Heying Birgit , Hoffmann Rolf‐Dieter , Rodewald Ute Ch. , Pöttgen Rainer
Published: May 2008

Well shaped single crystals of the equiatomic germanides YbPdGe and YbPtGe were synthesized from the elements using the Bridgman technique. The samples were investigated by X‐ray powder and single crystal diffraction: YbAuSn type, Imm2, a = 433.4(2), b = 2050.6(6), c = 752.6(2) pm, wR2 = 0.0723, 1551 F2 values, 58 variables for YbPdGe and TiNiSi type, Pnma, a = 686.32(9), b = 430.47(9), c = 751.02(8) pm, wR2 = 0.0543, 379 F2 values, 20 variables for YbPtGe. Both germanides crystallize with different superstructure variants of the KHg2 type, resulting from different stacking of the puckered Pd3Ge3 and Pt3Ge3 hexagons. While only Pt–Ge interactions occur in the [PtGe] polyanionic network of YbPtGe, weak interlayer Pd–Pd (297 pm) and Ge–Ge (275 pm) interactions occur in YbPdGe. The crystal chemical peculiarities are discussed in the light of the different superstructure formed.
Zur Reaktivität von alkylthioverbrückten 44‐CVE‐triangularen Platinclustern: Umsetzungen mit bidentaten Phosphanliganden
Authors: Albrecht Christian , Bruhn Clemens , Wagner Christoph , Steinborn Dirk
Published: May 2008

On the Reactivity of Alkylthio Bridged 44 CVE Triangular Platinum Clusters: Reactions with Bidentate Phosphine Ligands

The 44 cve (cluster valence electrons) triangular platinum clusters [{Pt(PR3)}3(μ‐SMe)3]Cl (PR3 = PPh3, 2a; P(4‐FC6H4)3, 2b; P(n‐Bu)3, 2c) were found to react with PPh2CH2PPh2 (dppm) in a degradation reaction yielding dinuclear platinum(I) complexes [{Pt(PR3)}2(μ‐SMe)(μ‐dppm)]Cl (PR3 = PPh3, 3a; P(4‐FC6H4)3, 3b; P(n‐Bu)3; 3e) and the platinum(II) complex [Pt(SMe)2(dppm)] (4), whereas the addition of PPh2CH2CH2PPh2 (dppe) to cluster 2a afforded a mixture of degradation products, among others the complexes [Pt(dppe)2] and [Pt(dppe)2]Cl2. On the other hand, the treatment of cluster 2a with PPh2CH2CH2CH2PPh2 (dppp) ended up in the formation of the cationic complex [{Pt(dppp)}2(μ‐SMe)2]Cl2 (5). Furthermore, the terminal PPh3 ligands in complex 3a proved to be subject to substitution by the stronger donating monodentate phosphine ligands PMePh2 and PMe2Ph yielding the analogous complexes [{Pt(PR3)}2(μ‐SMe)(μ‐dppm)]Cl (PR3 = PMePh2, 3c; PMe2Ph, 3d). NMR investigations on complexes 3 showed an inverse correlation of Tolmans electronic parameter ν with the coupling constants 1J(Pt,P) and 1J(Pt,Pt). All compounds were fully characterized by means of NMR and IR spectroscopy. X‐ray diffraction analyses were performed for the complexes [{Pt{P(4‐FC6H4)3}}2(μ‐SMe)(μ‐dppm)]Cl (3b), [Pt(SMe)2(dppm)] (4), and [{Pt(dppp)}2(μ‐SMe)2]Cl2 (5).
Sr5Ge2N6 – A Nitridogermanate with Edge‐sharing Double Tetrahedra
Authors: Junggeburth Sebastian C. , Oeckler Oliver , Schnick Wolfgang
Published: May 2008

The new nitridogermanate Sr5Ge2N6 was obtained as a coarsely crystalline product by Na‐flux technique employing a reaction of Sr, Na, NaN3 and GeO2 in weld shut tantalum‐tubes at temperatures up to 760 °C. The crystal structure was determined by single‐crystal X‐ray methods: (Sr5Ge2N6, space group C2/c (no. 15), a = 1040.8(2), b = 652.08(13), c = 1356.5(3) pm, β = 100.29(3)°, V = 905.8(3)·106 pm3, Z = 4, 1240 observed reflections, 61 parameters, R1 = 0.031). In the solid, there are edge‐sharing [Ge2N6]10− double tetrahedra surrounded by Sr2+ ions. Sr5Ge2N6 was found to be isotypic with Ca5Si2N6.
Subvalente Galliumtriflate – mögliche Ausgangsverbindungen für Clusterverbindungen des Galliums
Authors: Linti Gerald , Seifert Annekathrin
Published: May 2008

Subvalent Gallium Triflates – Potentially Useful Starting Materials for Gallium Cluster Compounds

By reaction of GaCp* with trifluormethanesulfonic acid in hexane a mixture of gallium trifluormethanesulfonates (triflates, OTf) is obtained. This mixture reacts readily with lithiumsilanides [Li(thf)3Si(SiMe3)2R] (R = Me, SiMe3) to afford the cluster compounds [Ga6{Si(SiMe3)Me}6], [Ga2{Si(SiMe3)3}4] and [Ga10{Si(SiMe3)3}6]. By crystallization from various solvents the gallium triflates [Ga(OTf)3(thf)3], [HGa(OTf)(thf)4]+ [Ga(OTf)4(thf)3]−, [Cp*GaGa(OTf)2]2 and [Ga(toluene)2]+ [Ga5(OTf)6(Cp*)2]− were isolated and characterized by single crystal X ray structure analysis.
Synthese und Kristallstruktur der Rhenium(VII)‐Nitridchloride ReNCl4 und ReNCl4·H2O
Authors: Binder Anja , Maichle‐Mössmer Cäcilia , Niquet Elke , Strähle Joachim
Published: May 2008

Syntheses and Crystal Structures of the Rhenium(VII) Nitride Chlorides ReNCl4 and ReNCl4·H2O

Rhenium(VII) nitride chloride, ReNCl4 (1) is obtained in form of brown needles with metallic luster by the reaction of ReCl5 with Cl3VNCl at 140 °C under vacuum in a sealed glass ampoule. It crystallizes in the tetragonal space group I4 with the lattice parameters a = 826.7(4), c = 405.1(2) pm, and Z = 2. The square pyramidal molecules are connected by asymmetric nitrido bridges to form chains along the crystallographic c axis. The shorter Re‐N distance of 163.0(5) pm corresponds to a triple bond, while the pronounced longer distance of 242.0(5) pm can be interpreted with a weak donor bond.

The reaction of ReCl5 with VN at 170 °C under vacuum in a sealed glass ampoule yields red needles of ReNCl4·H2O (2). It crystallizes in the orthorhombic space group Pnma with a = 1075.4(2), b = 1108.5(2), c = 547.7(5) pm and Z = 4. The Re atoms exhibit a distorted octahedral coordination with the aqua ligand in trans position to the nitrido ligand. The Re‐N triple bond has a bond distance of 166.1(11) pm. The complexes are connected by hydrogen bridges O‐H···N to form chains.
Facile Synthesis and Crystal Structure of 1,1,1,3‐Tetranitro‐3‐azabutane
Authors: Klapötke Thomas M. , Krumm Burkhard , Scherr Matthias , Spieß Gunnar , Steemann F. Xaver
Published: May 2008

The synthesis of 1,1,1,3‐tetranitro‐3‐azabutane is disclosed and compared with the known method. The structure of 1,1,1,3‐tetranitro‐3‐azabutane is identified by multi‐nuclear NMR spectroscopy and X‐ray single crystal structure determination.
Synthesis and Structural Characterization of Some Novel Trialkylsilyl‐substituted Lithium Benzyl Complexes [Li(tmeda)][CHRSiMe2R′] (R = Ph, 3,5‐Me2C6H3; R′ = Me, tBu, Ph)
Authors: Schumann Herbert , Freckmann Dominique M. M. , Dechert Sebastian
Published: May 2008

The reactions of PhCH2SiMe3 (1), PhCH2SiMe2tBu (2), PhCH2SiMe2Ph (3), 3,5‐Me2C6H3CH2SiMe3 (4), and 3,5‐Me2C6H3CH2SiMe2tBu (5) with nBuLi in tetramethylethylenediamine (tmeda) afford the corresponding lithium complexes [Li(tmeda)][CHRSiMe2R′] (R, R′ = Ph, Me (6), Ph, tBu (7), Ph, Ph (8), 3,5‐Me2C6H3, Me (9), and 3,5‐Me2C6H3, tBu (10)), respectively. The new compounds 5, 7, 8, 9 and 10 have been characterized by 1H and 13C NMR spectroscopy, compounds 7, 8 and 9 also by X‐ray structure analysis.
Encapsulation of Triphenylene Derivatives in the Hexanuclear Arene Ruthenium Metallo‐Prismatic Cage [Ru6(p‐PriC6H4Me)6(tpt)2(dhbq)3]6+ (tpt = 2,4,6‐tri(pyridin‐4‐yl)‐1,3,5‐triazine, dhbq = 2,5‐dihydroxy‐1,4‐benzoquinonato)
Authors: Govindaswamy Padavattan , Furrer Julien , Süss‐Fink Georg , Therrien Bruno
Published: May 2008

A large cationic triangular metallo‐prism, [Ru6(p‐PriC6H4Me)6(tpt)2(dhbq)3]6+ (1)6+, incorporating p‐cymene ruthenium building blocks, bridged by 2,5‐dihydroxy‐1,4‐benzoquinonato (dhbq) ligands, and connected by two 2,4,6‐tri(pyridin‐4‐yl)‐1,3,5‐triazine (tpt) subunits, allows the permanent encapsulation of the triphenylene derivatives hexahydroxytriphenylene, C18H6(OH)6 and hexamethoxytriphenylene, C18H6(OMe)6. These two cationic carceplex systems [C18H6(OH)6⊂1]6+ and [C18H6(OMe)6⊂1]6+ have been isolated as their triflate salts. The molecular structure of these systems has been established by one‐dimensional 1H ROESY NMR experiments as well as by the single‐crystal structure analysis of [C18H6(OMe)6⊂1][O3SCF3]6.
Das Lanthan‐Dodekahydro‐closo‐Dodekaborat‐Hydrat [La(H2O)9]2[B12H12]3·15 H2O und sein Oxonium‐Chlorid‐Derivat [La(H2O)9](H3O)Cl2[B12H12]·H2O
Authors: Tiritiris Ioannis , Schleid Thomas
Published: May 2008

The Lanthanum Dodecahydro‐closo‐Dodecaborate Hydrate [La(H2O)9]2[B12H12]3·15 H2O and its Oxonium‐Chloride Derivative [La(H2O)9](H3O)Cl2[B12H12]·H2O

By neutralization of an aqueous solution of the free acid (H3O)2[B12H12] with basic La2O3 and after isothermic evaporation colourless, face‐rich single crystals of a water‐rich lanthanum(III) dodecahydro‐closo‐dodecaborate hydrate [La(H2O)9]2[B12H12]3·15 H2O are isolated. The compound crystallizes in the trigonal system with the centrosymmetric space group $P{\bar 3}c$ (a = 1189.95(2), c = 7313.27(9) pm, c/a = 6.146; Z = 6; measuring temperature: 100 K). The crystal structure of [La(H2O)9]2[B12H12]3·15 H2O can be characterized by two of each other independent, one into another posed motives of lattice components. The [B12H12]2− anions (d(B–B) = 177–179 pm; d(B–H) = 105–116 pm) are arranged according to the samarium structure, while the La3+ cations are arranged according to the copper structure. The lanthanum cations are coordinated in first sphere by nine oxygen atoms from water molecules in form of a threecapped trigonal prism (d(La–O) = 251–262 pm). A coordinative influence of the [B12H12]2− anions on La3+ has not been determined. Since “zeolitic” water of hydratation is also present, obviously the classical H–Oδ–···+δH–O‐hydrogen bonds play a significant role in the stabilization of the crystal structure. During the conversion of an aqueous solution of (H3O)2[B12H12] with lanthanum trichloride an anion‐mixed salt with the composition [La(H2O)9](H3O)Cl2[B12H12]·H2O is obtained. The compound crystallizes in the hexagonal system with the non‐centrosymmetric space group $P{\bar 6}c {\rm 2}$ (a = 808.84(3), c = 2064.51(8) pm, c/a = 2.552; Z = 2; measuring temperature: 293 K). The crystal structure can be characterized as a layer‐like structure, in which [B12H12]2− anions and H3O+ cations alternate with layers of [La(H2O)9]3+ cations (d(La–O) = 252–260 pm) and Cl− anions along [001]. The [B12H12]2− (d(B–B) = 176–179 pm; d(B–H) = 104–113 pm) and Cl− anions exhibit no coordinative influence on La3+. Hydrogen bonds are formed between the H3O+ cations and [B12H12]2− anions, also between the water molecules of [La(H2O)9]3+ and Cl− anions, which contribute to the stabilization of the crystal structure.
Synthesis, Crystal Structure and Magnetism of the New Oxysulfide Ce3NbO4S3
Authors: Altmannshofer Sandra , Johrendt Dirk
Published: May 2008

The orange cerium‐niobium‐oxysulfide Ce3NbO4S3 was synthesized by the solid state reaction of CeO2, Ce‐metal, Nb2O5 and sulfur at 1100 °C. The crystal structure has orthorhombic symmetry (space group Pbam, a = 7.055(1), b = 14.571(3), c = 7.627(2) Å, Z = 4) and contains isolated [Nb2S4O6]10− ions consisting of two strongly distorted, edge sharing NbO3SS2/2 octahedra. Niobium is connected to three oxygen and three sulfur atoms. The cerium atoms are eightfold coordinated by oxygen and sulfur atoms. Certain oxygen and sulfur atoms are not connected to niobium, but exclusively surrounded by cerium. By connecting these cation polyhedra, one recognizes layers of $^{2}_{\infty}\rm [(Ce_{6}S_{2}O_{2})^{10+}]$ polycations perpendicular to the c‐axis. The magnetic susceptibility shows Curie‐Weiss behavior with an effective magnetic moment μeff = 2.63(1) μB/Ce in agreement with Ce3+. A Weiss‐constant θp = –12(1) K indicates weak antiferromagnetic coupling. No magnetic ordering was detected above 2 K.
Synthesis and Crystal Structures of Novel Copper(I) Complexes of a Phosphanylborane
Authors: Schwan Karl‐Christian , Adolf Ariane , Bodensteiner Michael , Zabel Manfred , Scheer Manfred
Published: May 2008

The novel copper iodide clusters [Cu3(μ‐I)(μ3‐I)2(PH2BH2·NMe3)3] (2) and [Cu4(μ‐I)2(μ3‐I)2(PH2BH2·NMe3)3] (3) were synthesized by treating CuI with the primary phosphine (H2PBH2·NMe3). The novel features of both compounds, which have been characterized by X‐ray crystallography, are the unsymmetrical constitution of the copper iodide core due to the influence of the monodentate phosphorus ligand. This results in copper atoms with different coordination numbers within the compound. Complex 2, the major product of the reaction, contains a distorted octahedral Cu3I3‐core, in which one vertex is missing. Complex 3 was isolated as a by‐product and is composed of a Cu4I4‐core in a distorted octahedral coordination.
8‐Amidoquinoline, 8‐(Trialkylsilylamido)quinoline, 2‐Pyridylmethylamide, and (2‐Pyridylmethyl)(trialkylsilyl)amide Complexes of Gallium
Authors: Koch Christian , Görls Helmar , Westerhausen Matthias
Published: May 2008

Lithium 8‐amidoquinoline (1) and lithium 8‐(trialkylsilylamido)quinoline [SiMe2tBu (2), SiiPr3 (3)] react with dimethylgallium chloride to the metathesis products dimethylgallium 8‐amidoquinoline (4) as well as dimethylgallium 8‐(trialkylsilylamido)quinoline [SiMe2tBu (5), SiiPr3 (6)]. The gallium atoms are in distorted tetrahedral environments. During the synthesis of 5, orange dimethylgallium 2‐butyl‐8‐(tert‐butyldimethylsilylamido)quinoline (7) was found as by‐product. The metathesis reactions of Me2GaCl with LiN(R)CH2Py (Py = 2‐pyridyl) yield the corresponding 2‐pyridylmethylamides Me2Ga‐N(H)CH2Py (8), Me2Ga‐N(SiMe2tBu)CH2Py (9) and Me2Ga‐N(SiiPr3)CH2Py (10). In these complexes the gallium atoms show a distorted tetrahedral coordination sphere. However, derivative 8 crystallizes dimeric with bridging amido units whereas in 9 and 10 the 2‐pyridylmethylamido moieties act as bidentate ligands leading to monomeric molecules.
Lanthanide(II) Complexes of the Dihydrotriazinido Ligand [N{C(Ph)=N}2C(tBu)Ph]−
Authors: Hitchcock Peter B. , Khvostov Alexei V. , Lappert Michael F. , Protchenko Andrey V.
Published: May 2008

The potassium dihydrotriazinide K(LPh,tBu) (1) was obtained by a metal exchange route from [Li(LPh,tBu)(THF)3] and KOtBu (LPh,tBu = [N{C(Ph)=N}2C(tBu)Ph]). Reaction of 1 with 1 or 0.5 equivalents of SmI2(thf)2 yielded the monosubstituted SmII complex [Sm(LPh,tBu)I(THF)4] (2) or the disubstituted [Sm(LPh,tBu)2(THF)2] (3), respectively. Attempted synthesis of a heteroleptic SmII amido‐alkyl complex by the reaction of 2 with KCH2Ph produced compound 3 due to ligand redistribution. The YbII bis(dihydrotriazinide) [Yb(LPh,tBu)2(THF)2] (4) was isolated from the 1:1 reaction of YbI2(THF)2 and 1. Molecular structures of the crystalline compounds 2, 3·2C6H6 and 4·PhMe were determined by X‐ray crystallography.
The Role of the “Ligand Periphery” in the Coordination of Tripodal Triamidostannates(II) to Iridium: Simple Ligation vs. Cyclometallation
Authors: Kilian Michaela , Wadepohl Hubert , Gade Lutz H.
Published: May 2008

Reaction of the triamidostannates(II) MeSi{SiMe2N(3,5‐xyl)}3SnLi(OEt2) (2a) and MeSi{SiMe2N(p‐tol)}3SnLi(OEt2) (2b) with [IrCl(CO)(PPh3)2] gave the IrI‐Sn complex [MeSi{SiMe2N(3,5‐xyl)}3SnIr(PPh3)2(CO)] (3a) for the former. In contrast, for the tolyl stannate CH‐activation occurred to give the IrIII compound [MeSi{SiMe2N(p‐tol)}2{SiMe2N(2‐C6H3‐4‐CH3)}SnIr(H)(PPh3)2(CO)] (3b). The latter is thus avoided by introduction of suitably placed substituents in the peripheral aryl groups of the triamidostannate ligand.
Preparation and Crystal Structure of the Neodymium Borohydride [Li(thf)4]2[Nd2(μ‐Cl)2(BH4)6(thf)2]
Authors: Klein Axel , Pohl Roland W. H.
Published: May 2008

The neodymium borohydride [Li(thf)4]2[Nd2(μ‐Cl)2(BH4)6(thf)2] was synthesized from neodymium chloride and lithium borohydride. The compound crystallized in the triclinic crystal system, space group $P{\bar 1}$ (No. 2) with the cell constants a = 14.8613(11), b = 17.8715(13), c = 23.5846(18) Å, α = 100.760(6), β = 90.648(6) and γ = 103.294(6)°. Each neodymium atom is coordinated by three borohydride anions and a THF molecule whereas two neodymium cations are bridged through two chloro ligands. The charge of the [Nd2(μ‐Cl)2(BH4)6(thf)2]2− anion, which represents the first structurally characterized binuclear mixed borohydride chlorido complex, is compensated by two [Li(thf)4]+ cations.
1,4,6,9‐Tetraoxa‐5λ4‐selena‐spiro[4.4]nonane – A Combined Theoretical and Experimental Study
Authors: Betz Richard , Pfister Maximilian , Reichvilser Moritz M. , Klüfers Peter
Published: May 2008

The symmetric spiro‐selenurane derived from ethylene glycol, 1,4,6,9‐tetraoxa‐5λ4‐selena‐spiro[4.4]nonane, was prepared from selenium tetrachloride and ethylene glycol and its molecular structure was determined by single crystal X‐ray diffraction. NBO analyses for the title compound and a related compound were conducted to assess the role of the stereochemical active lone pair on the selenium atom on the structure.
Adducts of Cyclodiphosph(V)azenes: Synthesis and Structure
Authors: Hubrich Christopher , Michalik Dirk , Schulz Axel , Villinger Alexander
Published: May 2008

The reaction of Ph2PCl and PhPCl2 with bis(trimethylsilyl)sulfur diimide in the presence of GaCl3 and AlCl3 yields diadducts of the corresponding cyclodiphosph(V)azene: [Ph2PN]2·(GaCl3)2 (1), [Ph2PN]2·(AlCl3)2 (2), and [Ph(Cl)PN]2·(AlCl3)2 (3). This reaction is triggered by Lewis acids, which catalyse the (CH3)3Si‐Cl and S8 elimination. The structures of 1·2 CH2Cl2, 2·2 CH2Cl2 and 3 were determined by single crystal X‐ray studies (1: triclinic, $P{\bar 1}$, a = 9.679(2) Å, b = 9.863(2) Å, c = 11.366(2) Å, α = 113.55(3)°; β = 99.59(3)°; γ = 106.67(3)°; V = 902.8(3) Å3, Z = 1; 2: triclinic, $P{\bar 1}$, a = 9.639(2) Å, b = 9.804(2) Å, c = 11.321(2) Å, α = 113.71(3)°; β = 99.44(3)°; γ = 106.70(3)°; V = 889.3(3) Å3, Z = 1; 3: orthorhombic, Pbca, a = 14.853(3) Å, b = 9.261(2) Å, c = 16.631(3) Å, V = 2287.7(8) Å3, Z = 4.
A Manganese(II) Coordination Polymer with Ditopic Bis(pyrazol‐1‐yl)borate Bridges
Authors: Morawitz Thorsten , Bolte Michael , Lerner Hans‐Wolfram , Wagner Matthias
Published: May 2008

The synthesis and characterization of the ditopic bis(pyrazol‐1‐yl)borate ligand Li2[p‐C6H4(B(C6F5)pz2)2] is reported (pz = pyrazol‐1‐yl). Compared to the corresponding t‐butyl derivative Li2[p‐C6H4(B(t‐Bu)pz2)2], the C6F5‐substituted scorpionate is significantly more stable towards hydrolysis. Reaction of Li2[p‐C6H4(B(C6F5)pz2)2] with two equivalents of MnCl2 leads to the formation of coordination polymers {(MnCl2)2(Li(THF)3)2[p‐C6H4(B(C6F5)pz2)2]}∞ featuring penta‐coordinate MnII ions chelated by one bis(pyrazol‐1‐yl)borate fragment and further bonded to three chloride ions. Two of the three chloride ions are also coordinated to a neighbouring MnII ion; the third chloro ligand is shared between the MnII centre and a Li(THF)3 moiety.
An Unusual Product from the Reaction of C(PPh3)2 with [Mn2(CO)10]: Formation and Crystal Structure of [Mn(OPPh3)2{O2CC(PPh3)2}2][Mn(CO)5]2
Authors: Petz Wolfgang , Öxler Florian , Ronge Ramona , Neumüller Bernhard
Published: May 2008

The carbodiphosphorane C(PPh3)2 (1) reacts with [Mn2(CO)10] in THF to produce quantitatively the salt‐like complex (HC{PPh3}2)[Mn(CO)5] (2) as THF solvate. If the reaction is carried out in 1,2‐dimethoxyethane (DME) small amounts of [Mn(OPPh3)2{O2CC(PPh3)2}2][Mn(CO)5]2 (3) as DME solvate along with solvent free 2 as the main product were isolated. Proton abstraction from the solvent led to the formation of 2; the ligands OPPh3 and O2CC(PPh3)2}2 of 3 are the results of a side reaction from [Mn2(CO)10] and 1 in a Wittig type manner. From the reaction in benzene small amounts of 3 were also obtained, crystallizing as benzene solvate 3·4C6H6. The crystal structures of 2·THF, 2, 3·1.75DME and 3·4C6H6 are reported. The compounds are further characterized by IR and 31P NMR spectroscopy.