Tris(pyridyl)borates: an emergent class of versatile and robust polydentate ligands for catalysis and materials applications.

Tridentate ligands that incorporate pyridyl rather than pyrazolyl groups are emerging as an attractive class of "scorpionate"-type ligands with enhanced electron donation, increased stability, and divergent geometry at the metal centre relative to tris(pyrazolyl)borates originally introduced by Trofimenko. Following our initial reports, the tris(pyridyl)borate (Tpyb) ligand architecture has been adopted by several research groups in pursuit of functional metal complexes that offer new opportunities in catalysis and materials science. While earlier work had been focused on symmetric octahedral complexes, ML, which are advantageous as highly robust building blocks in materials sciences, recently introduced new ligand designs provide access to heteroleptic metal complexes with vacant sites that lend themselves to applications in catalysis.

Electrophilic and nucleophilic displacement reactions at the bridgehead borons of tris(pyridyl)borate scorpionate complexes.

Although a wide variety of boron-based "scorpionate" ligands have been implemented, a modular route that offers facile access to different substitution patterns at boron has yet to be developed. Here, we demonstrate new reactivity patterns at the bridgehead positions of a ruthenium tris(pyrid-2-yl)borate complex that allow for facile tuning of steric and electronic properties.

ROMP-Boranes as Moisture-Tolerant and Recyclable Lewis Acid Organocatalysts.

Although widely used in catalysis, the multistep syntheses and high loadings typically employed are limiting broader implementation of highly active tailor-made arylborane Lewis acids and Lewis pairs. Attempts at developing recyclable systems have thus far met with limited success, as general and versatile platforms are yet to be developed. We demonstrate a novel approach that is based on the excellent control and functional group tolerance of ring-opening metathesis polymerization (ROMP).

Solvent Retention and Crack Evolution in Dropcast PEDOT:PSS and Dependence on Surface Wetting.

The drying of nanocolloidal polymers is governed by the interplay among surface tension, evaporation, and contact-line pinning, among other phenomena. Here, we describe the sequential evolution of poly-3,4-ethylenedioxythiophene:poly(styrene sulfonate) (PEDOT:PSS) through two distinct regimes evidenced by annular or radial cracking and show that the cracking dynamics and solvent-retention postdrying and postcracking are mediated by wetting to the substrate surface. The corresponding changes in the PEDOT:PSS morphology are also observed to relate to the radial or cracking dynamics.

Long-Range Self-Assembly via the Mutual Lorentz Force of Plasmon Radiation.

Long-range interactions often proceed as a sequence of hopping through intermediate, statistically favored events. Here, we demonstrate predictable mechanical dynamics of particles that arise from the Lorentz force between plasmons. Even if the radiation is weak, the nonconservative Lorentz force produces stable locations perpendicular to the plasmon oscillation; over time, distinct patterns emerge.