Search

Several pyrrole-pyridin-based dibranched, heterocyclic 'push-pull' chromophore systems are synthesized and characterized. NMR and optical spectroscopy define the molecular structures and other physiochemical properties of chromophore monolayers and thin-film characterization emphasizes the importance of the chromophore molecular structure and film growth method on film microstructure and optical/electrooptic response.

A study on the activation of C-C and C-F bonds through the insertion of platinum group metal complexes in solution reports on the consecutive C-C activation and C-F cleavage in one chemical system. The process involves selective metal insertion into a very strong aryl-CF3 C-C bond followed by reaction of the resulting RhIII-CF3 complex with protonic or Lewis acids to form unique difluoromethylene-arenium complexes by C-F cleavage and C-C bond formation.

Submolecular electrical information is successfully derived by applying element-specific, chemically resolved electrical measurements to a covalently bound stilbazole-based monolayer on a silicon substrate. The pronounced affinity effects are found in response of adjacent atomic sites to external charge injection, accompanied by intramolecular polarization variations.

Metal-organic networks (MONs) are created by a stepwise solution deposition approach from vinylpyridine-based building blocks and Pd[Cl.sub.2]. The X-ray photoelectron spectroscopy (XPS) elemental composition has shown the formation of a palladium coordination-based network.

The first application of self-propagating molecule-based assemblies (SPMAs) as efficient electron-transporting layers for inverted organic photovoltaic (OPV) cells is reported. The findings for the dependence of cell response parameters on interlayer thickness could be used to optimize device performance.

A metallo-supramolecular network has undergone reversible redox chemistry on indium-tin oxide (ITO) coated glass substrates with concurrent color change. The switching time, long-term stability, and coloration efficiency are competitive with polymeric materials such as the PEDOT.

A hybrid structure consisting of a robust and structurally well-defined polypyridyl osmium complex and palladium precursor are constructed by using an iterative two-step assembly method. The studies have shown that the important characteristics of polyelectrolyte-based films and the molecular self-assembly (SA) are analogous, showing that the rich chemistry of surfaces engineered with molecular-based multilayers are extended to the functions of polyelectrolyte-based films.

The article discusses the properties and growth of the crystalline halogen-bonded thin films that are self-assembled on silicon substrates by the method of physical vapor deposition (PVD). The microstructures of the films are shown to be completely independent of the chemistry of the substrate surface.

The exclusive activation of a strong aryl-Br bond of a halogenated vinylarene by nickel(0) in the presence of aryl-I containing substrates is described. The reaction has obeyed first-order kinetics in the [[eta].sup.2]-coordination complexes with identical activation parameters for Br and I derivatives and the ring-walking process is shown to be kinetically accessible.

The NMR spectroscopy was used to study the fluxional behavior of two analogous platinum complexes and demonstrate their reaction mechanism and determine the activation parameters. The results from NMR spectroscopy showed that the migration of the metal center between the C=C bonds involves an intramolecular process.

A highly ordered molecular-based material is described by using a hierarchical approach where the stronger metal-organic coordination has governed the order in the direction of growth and the weaker, sterically demanding, [pi]-[pi] interactions have tuned the lateral stability. The interactions are shown to be interdependent as the in-plane ordering has induced structural regularity in the axial direction.

The selective optical detection and parts per million level quantification of [Cr.sup.6+] in acidic [H.sub.2]O and MeCN are described by using known 1-based monolayers on float glass substrates. The combined physicochemical properties and device performance of the 1-based monolayer, including robustness, stability, selectivity, response time, as well as low detection limits, have made this system an excellent alternative for detecting and quantifying [Cr.sup.6+].

The solution-based layer-by-layer formation of palladium-organic assemblies is described and the effect of the nature of the employed palladium precursors on multilayer structure and optical properties are compared. A report on the refractive index of the material formed and on the bottom-up three-dimensional (3D) assembly of a multilayer on a photo-patterned monolayer is presented.

The optical detection of parts-per million (ppm)-levels of [H.sub.2]O in organic media using osmium chromophore (I)-based monolayers on glass is presented. The analysis of performance characteristics, including reversibility, reproducibility, stability, and the detection limit of the sensor, reveal a new entry for the ppm-level detection and quantification of [H.sub.2]O in organic solvents.

Vinylation of aryl halides, also known as the Heck reaction, may be catalyzed using electron-rich trigonal bisphosphine palladium(0) complexes. These reactions exhibit a chelate effect and enable Heck coupling under reducing conditions in the absence of a base, although at a moderate rate. The novel complexes were prepared by treatment of Pd(TFA)2 (TFA=OCOCF3) with corresponding diphosphines in THF at 80 degrees centigrade. Very high turnover numbers and yields were observed for all the catalyst complexes.