A 2D chiral microcavity based on apparent circular dichroism.

Engineering asymmetric transmission between left-handed and right-handed circularly polarized light in planar Fabry-Pérot (FP) microcavities would enable a variety of chiral light-matter phenomena, with applications in spintronics, polaritonics, and chiral lasing. Such symmetry breaking, however, generally requires Faraday rotators or nanofabricated polarization-preserving mirrors. We present a simple solution requiring no nanofabrication to induce asymmetric transmission in FP microcavities, preserving low mode volumes by embedding organic thin films exhibiting apparent circular dichroism (ACD); an optical phenomenon based on 2D chirality.

Optical monitoring of polymerizations in droplets with high temporal dynamic range.

The ability to optically monitor a chemical reaction and generate an readout is an important enabling technology, with applications ranging from the monitoring of reactions in flow, to the critical assessment step for combinatorial screening, to mechanistic studies on single reactant and catalyst molecules. Ideally, such a method would be applicable to many polymers and not require only a specific monomer for readout. It should also be applicable if the reactions are carried out in microdroplet chemical reactors, which offer a route to massive scalability in combinatorial searches.

Role of sterics in phosphine-ligated gold clusters.

This study examined the solution-phase exchange reactions of triphenylphosphine (PPh3) ligands on Au8L72+ (L = PPh3) gold clusters with three different tolyl ligands using electrospray ionization mass spectrometry to provide insight into how steric differences in the phosphines influence the extent of ligand exchange and the stability of the resulting mixed-phosphine clusters. The size distributions of tolyl-exchanged gold clusters were found to depend on the position of the methyl group in the tri(tolyl)phosphine ligands (-ortho, -meta, and -para). Due to different sterics, the tri(m-tolyl)phosphine (TMTP) and tri(p-tolyl)phosphine (TPTP) ligands exchanged efficiently onto the Au8L72+ (L = PPh3) clusters while the tri(o-tolyl)phosphine ligands did not exchange.