Complex structural dynamics of nanocatalysts revealed in Operando conditions by correlated imaging and spectroscopy probes.

Understanding how heterogeneous catalysts change size, shape and structure during chemical reactions is limited by the paucity of methods for studying catalytic ensembles in working state, that is, in operando conditions. Here by a correlated use of synchrotron X-ray absorption spectroscopy and scanning transmission electron microscopy in operando conditions, we quantitatively describe the complex structural dynamics of supported Pt catalysts exhibited during an exemplary catalytic reaction-ethylene hydrogenation. This work exploits a microfabricated catalytic reactor compatible with both probes.

A novel X-ray diffractometer for studies of liquid-liquid interfaces.

The study of liquid-liquid interfaces with X-ray scattering methods requires special instrumental considerations. A dedicated liquid surface diffractometer employing a tilting double-crystal monochromator in Bragg geometry has been designed. This diffractometer allows reflectivity and grazing-incidence scattering measurements of an immobile mechanically completely decoupled liquid sample, providing high mechanical stability.

Phenalenone-type phytoalexins mediate resistance of banana plants (Musa spp.) to the burrowing nematode Radopholus similis.

The global yield of bananas-one of the most important food crops-is severely hampered by parasites, such as nematodes, which cause yield losses up to 75%. Plant-nematode interactions of two banana cultivars differing in susceptibility to Radopholus similis were investigated by combining the conventional and spatially resolved analytical techniques (1)H NMR spectroscopy, matrix-free UV-laser desorption/ionization mass spectrometric imaging, and Raman microspectroscopy. This innovative combination of analytical techniques was applied to isolate, identify, and locate the banana-specific type of phytoalexins, phenylphenalenones, in the R.

Exploring quality in gradient copolymers.

Quality of gradient copolymers is evaluated by atomic force microscopy (AFM) and correlated with molecular weight distribution (MWD) values. ARGET ATRP is employed with decreasing levels of catalyst concentrations to generate copolymers with increasing M¯w/M¯n values. The copolymers are transformed into molecular bottlebrushes to enable imaging and analysis of individual molecules by AFM.

Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization in Miniemulsion with 50 ppm of Copper Catalyst.

The design and synthesis of a powerful ligand is reported for use in activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) in miniemulsion. The structure of ',″-dioctadecyl-',″-bis[2-(4-methoxy-3,5-dimethyl)pyridylmethyl]ethane-1,2-diamine (DOD-BPED*) was formulated to produce a tetradentate ligand which was both hydrophobic and highly active. Studies in homogeneous ARGET ATRP with CuBr/DOD-BPED* demonstrated a high degree of control, similar to those ligands traditionally used.