Preparation,structure and catalytic properties of a binuclear Pd(0) complex with bridging silylene ligands

In contrast to the N-heterocyclic carbene (NHC) 1, the homologous N-heterocyclic silylene (NHS) 4 acts as a bridging ligand to Pd(0), giving rise to the dinuclear complex 5 which is catalytically active in Suzuki reactions.     

Assemblies from metallic and semiconducting nanocrystals

Optical properties of nanomaterials such as semiconductor and metal quantum dots are important for sensors and photovoltaic applications. We report on optical, microscopic, and AFM investigations on bulk and single nanoobjects such as metal and semiconducting nanoparticles. Firstly, of special interest is the investigation of Ag metal nanoaggregates formed in zeolites. Here, the defined structure of the zeolite serves both as size directing and a stabilizing agent. The size selected Ag aggregates fluoresce in the zeolite cages even after storage under ambient conditions for almost one year. In addition, single Ag particles escape the cages and can be investigated by fluorescence microscopy also with respect to sensor applications. Secondly, with respect to photovoltaic applications, energy transfer among organic dye molecules and semiconductor quantum dots is of great importance. We report on the extension of the optical absorption of ZnSe quantum dots into the UV regime and investigate excitation energy transfer within self-assembled nanoaggregates of surface functionalized QDs and fluorescent styrylpyridine dyes.     

Catalytic stereoselective synthesis of α-Amino phosphonic acid derivatives by asymmetric hydrogenation

The phosphonate analogue of α-N-benzoyl protected phenylalanine methylester has been prepared by catalytic synthesis. Commonly used Rh-complexes has been applied in asymmetric hydrogenation to check their usefulness in the standard reaction.     

Electroactive Polymers: Developments of and Perspectives for Dielectric Elastomers

We present the development and applications of dielectric elastomers. For the last 10 years the significance of this class of polymers has risen as more applications seem possible and first products have been commercialized.     

Traveling Salesman Problem with Clustering

In the original traveling salesman problem, the traveling salesman has the task to find the shortest closed tour through a proposed set of nodes, touching each node exactly once and returning to the initial node at the end. For the sake of the tour length to be minimized, nodes close to each other might not be visited one after the other but separated in the tour. However, for some practical applications, it is useful to group nodes to clusters, such that all nodes of a cluster are visited contiguously. Here we present an approach which leads to an automatic clustering with a clustering parameter governing the sizes of the clusters.     

Conductor‐like screening model for relaxed excited states: Implementation in the semiempirical method MSINDO

Two approaches to treat solvent polarization and reorientation effects for excited states of molecules and surfaces have been implemented in the recently developed MSINDO‐sCIS method (Gadaczek, Krause, Hintze, Bredow, J. Chem. Theory Comput. 2011, 7, 3675). They allow for an efficient calculation of analytical energy gradients and hence open the opportunity to investigate fluorescence effects or photochemical reactions in solution for large molecules that are difficult to treat with high‐level methods. Both approaches are based on the conductor‐like screening model (COSMO) (Klamt and Schüürmann, J. Chem. Soc., Perkin Trans. 1993, 2, 799) in combination with the configuration interaction singles (CIS) method (Foresman, Head‐Gordon, Pople, and Frisch, J. Phys. Chem. 1992, 96, 135). The paper gives a brief outline of the theoretical background. As a first application, solvent shifts of three well‐studied, environment‐sensitive fluorescent dyes (Kucherak, Didier, Mély, and Klymchenko, J. Phys. Chem. Lett. 2010, 1, 616) have been calculated and compared with experimental results and standard time‐dependent density functional theory. A statistical evaluation of MSINDO‐COSMO‐sCIS is provided for a set of 39 molecules suggested recently by Jacquemin et al. (Jacquemin, Planchat, Adamo, and Mennucci, J. Chem. Theory Comput. 2012, 8, 2359). Calculated vertical and adiabatic excitation energies and fluorescence energies are compared to experimental data. © 2014 Wiley Periodicals, Inc.