Synthesis and Crystal Structures of Copper Zinc Phenylthiolate and the First Copper Zinc Selenolate and Tellurolate Complexes

Five copper zinc phenylchalcogenolate complexes [(iPr₃PCu)₃(ZnMe₂)₂(SPh)₃] ( 1 ), [(iPr₃PCu)₂(ZnPh)₄(SPh)₆] ( 2 ), [(iPr₃PCu)₂(ZnEt)₄(SPh)₆] ( 3 ), [(iPr₃PCu)₃(ZnEt)(SePh)₄] ( 4 ), and [(iPr₃PCu)₃Cu(iPr₃PZn)(TePh)₆] ( 5 ) were synthesized by the reaction of phosphine stabilized copper phenylchalcogenolate complexes with ZnR₂ (R = Me, Et, Ph) with and without additional chalcogenol. The novel mixed metal compounds were characterized by single‐crystal X‐ray structure analysis and NMR spectroscopy. 4 and 5 are the first examples of compounds with a Zn–Se–Cu or a Zn–Te–Cu linkage, respectively.     

Synthesis,Crystal Structure,and Luminescence of Metal Iodide Cluster Compounds (nBu4N)2[M6I8(NCO)6] with M = Mo,W

Molybdenum and tungsten iodide clusters with the [M₆I₈] cluster core show versatile photophysical properties that strongly depend on the nature of six apical ligands (L) in [M₆I₈L₆]^2–. In course of our syntheses we report a new efficient preparation of Cs₂[Mo₆I₁₄] as precursor. Target compounds (ⁿBu₄N)₂[M₆I₈(NCO)₆] with M = Mo, W with cyanate ligands were synthesized and structurally characterized to study their photophysical properties. (ⁿBu₄N)₂[M₆I₈(NCO)₆] compounds appear as deep red (Mo) and light yellow (W) crystal powders showing strong phosphorescence. Compared to other cluster compounds of this type there is no significant concentration quenching obtained by the presence of molecular oxygen.     

Improved outcoupling of light in organic light emitting devices, utilizing a holographic DFB-structure

In this work organic light emitting devices (OLEDs) were fabricated implementing gratings, in order to extract waveguided electroluminescence (EL). The gratings were recorded by exposing thin films of the molecular azo glass N, N′-bis (4-phenyl)-N, N′-bis [(4-phenylazo)-phenyl] benzidine (AZOPD) to holographic light patterns. The photopatterned AZOPD serves as hole transport material for devices with aluminum-tris(8-hydroxyquinoline) doped with 1% of 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (Alq₃:DCM) as emissive/electron transport layer. The corrugated devices showed enhanced emission in the forward direction. The emitted light is polarized preferably parallel to the grating lines. In addition, we have found a doubling in the total luminance with respect to the unstructured device.     

Eine Mikro-Trockenapparatur

Ohne Zusammenfassung     

Physikalische und physikochemische Methoden und Apparate in der Mikrochemie

Ohne Zusammenfassung     

Change of non-crystalline orientational distribution in polyethylene blown films during drawing (fluorescent probe technique)

Summary The 2nd and 4th moment of the orientation distribution function of the non-crystalline regions of polyethylene blown films are determined during umaxial drawing by use of incorporated fluorescent probe molecules. In the initial state of the films the orientational parameters indicate an approximately random orientational distribution irrespective of the used probe molecule.The measured orientation during drawing is the result of averaging a probe dependent number of polymer segments which are correlated in their orientation to the probe's geometry.The inhomogeneity of deformation in the non-crystalline regions is indicated using probe molecules which undergo conformational changes due to deforming microregions.It is shown, that the accuracy of the 4^th moment results depends, more strongly than the 2nd moment, on the proper correcture of both the non-ideal photophysical probe properties and the crystallite light scattering. Nevertheless, deviations of the affine deformation can be shown by the 4th moment results.The apparatus for measuring polarized fluorescence and the evaluation method are described; an automatic control and data acquisition unit has been developed.

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Zusammenfassung Mit Hilfe von eingelagerten Fluoreszenzsonden wurden das 2. und 4. Moment der Orientierungsverteilung in den nichtkristallinen Bereichen von Polyäthylenblasfolien während einer uniaxialen Verstreckung bestimmt. Diese Orientierungsparameter zeigen bei allen eingesetzten Sondenmolekülen eine nahezu isotrope Orientierungsverteilung im Ausgangszustand der untersuchten Blasfolien; je nach dem Sondentyp wird während der Verstreckung die Polymerkettenorientierung als Mittelung einer sondenspezifi-schen Segmentzahl mit einer durch die Sondengeometrie bestimmten Lagekorrelation erhalten.Mit Sondenmolekülen, die aufgrund der Deformation von Mikrobereichen innerhalb des Nichtkristallinen Konformationsänderungen erfahren, werden Deformationsinhomogenitäten nachgewiesen. Es wird gezeigt, daß nicht ideale photophysikalische Sondeneigenschaften und Lichtstreuung an den Kristalliten die Bestimmung des 4. Moments stärker stören als die des 2. Moments. Trotzdem können mit Hilfe des 4. Moments die Abweichungen von der affinen Deformation nachgewiesen werden.Die Apparatur zur Messung der polarisierten Fluoreszenz, die durch Entwicklung einer Ablaufsteuerung automatisiert wurde, und das Auswerteverfahren werden beschrieben.

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With 4 figures and 3 tables     

A new method for the gradient‐based optimization of molecular complexes

We present a novel method for the local optimization of molecular complexes. This new approach is especially suited for usage in molecular docking. In molecular modeling, molecules are often described employing a compact representation to reduce the number of degrees of freedom. This compact representation is realized by fixing bond lengths and angles while permitting changes in translation, orientation, and selected dihedral angles. Gradient‐based energy minimization of molecular complexes using this representation suffers from well‐known singularities arising during the optimization process. We suggest an approach new in the field of structure optimization that allows to employ gradient‐based optimization algorithms for such a compact representation. We propose to use exponential mapping to define the molecular orientation which facilitates calculating the orientational gradient. To avoid singularities of this parametrization, the local minimization algorithm is modified to change efficiently the orientational parameters while preserving the molecular orientation, i.e. we perform well‐defined jumps on the objective function. Our approach is applicable to continuous, but not necessarily differentiable objective functions. We evaluated our new method by optimizing several ligands with an increasing number of internal degrees of freedom in the presence of large receptors. In comparison to the method of Solis and Wets in the challenging case of a non‐differentiable scoring function, our proposed method leads to substantially improved results in all test cases, i.e. we obtain better scores in fewer steps for all complexes. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009     

On a class of finite dimensional contractive perturbations of restricted shifts of finite multiplicity

We study a class of finite-dimensional contractive perturbations of shift operators of finite multiplicity restricted to left invariant subspaces of vectorialH ² spaces. We determine their spectra in terms of the characteristic function of the unperturbed operator and the perturbation. Partially supported by the Batsheva de Rothschild Fund for the Advancement of Science and Technology.     

Electric field assisted holographic recording of surface relief gratings in an azo-glass

The formation of holographic gratings in an azo-glass is investigated for the simple case of an intensity grating in the s-polarization of the recording beams. A dual grating is formed as a function of time with a refractive index grating and a relief grating. The diffraction efficiency as a function of recording time is discussed in a model of two consecutive processes with a phase shift. A material transport process is involved in the formation of relief patterns. An additional electrical corona field perpendicular to the sample leads to a magnification of the relief pattern. This process also works in case of a homogeneous exposure. PACS 78.66.Qn; 42.40.Eq; 42.70