Attached Nitrogen Test by C-N Solid-State NMR Spectroscopy for the Structure Determination of Heterocyclic Isomers.

Differentiation of heterocyclic isomers by solution H, C, and N NMR spectroscopy is often challenging due to similarities in their spectroscopic signatures. Here, C{N} solid-state NMR spectroscopy experiments are shown to operate as an "attached nitrogen test", where heterocyclic isomers are easy to distinguish based on one-dimensional nitrogen-filtered C solid-state NMR. We anticipate that these NMR experiments will facilitate the assignment of heterocyclic isomers during synthesis and natural product discovery.

Molecular Conformation in Charge Tunneling across Large-Area Junctions.

Self-assembled monolayers are predicated on thermodynamic equilibrium; hence, their properties project accessible relaxation pathways. Herein, we demonstrate that charge tunneling correlates with conformational degrees of freedom(s). Results from open chain and cyclic head groups show that, as expected, distribution in tunneling data correlates with the orientation of the head group, akin to the odd-even effect and more importantly the degree of conformational freedom, but fluctuates with applied bias.

Synthesis and Spectral Properties of Push-Pull Dyes Based on Isobenzofuran Scaffolds.

A new class of push-pull dyes based on the reactive isobenzofuran core have been synthesized. The new dyes have a smaller HOMO-LUMO gap than a related class of dyes based on benzofurazan and allow for isolation of structural factors that contribute to environmental sensitivity. Experimental and theoretical evidence implicate different photophysical processes are responsible for a reversal of emissive behavior that is observed between isobenzofuran and benzofurazan analogues.