A pedagogical approach to science outreach.

Encouragement of students across all communities through scientific outreach programs is critical to engaging the next generation, exciting young minds to pursue careers in science and medicine. Herein, we present a uniquely structured and widely influential science outreach program. Founded in 2005, the Duke Chemistry Outreach (DCO) employs a pedagogical approach to outreach that aims to teach its audience a new scientific concept, while instilling a pure enjoyment of science. DCO has performed 583 events reaching over 70,000 participants throughout 2,270 hours, with the majority of events in Durham, the surrounding North Carolinian communities, and across 8 other states. The flexibility and diversity of this outreach program creates a framework amendable for others to adopt in both secondary and higher education settings.

Single-Molecule Activation and Quantification of Mechanically Triggered Palladium-Carbene Bond Dissociation.

Metal-complexed N-heterocyclic carbene (NHC) mechanophores are latent reactants and catalysts for a range of mechanically driven chemical responses, but mechanochemical scission of the metal-NHC bond has not been experimentally characterized. Here we report the single-molecule force spectroscopy of ligand dissociation from a pincer NHC-pyridine-NHC Pd(II) complex. The force-coupled rate constant for ligand dissociation reaches 50 s-1 at forces of approximately 930 pN. Experimental and computational observations support a dissociative, rather than associative, mechanism of ligand displacement, with rate-limiting scission of the Pd-NHC bond followed by rapid dissociation of the pyridine moiety from Pd.

Metal-binding hydrazone photoswitches for visible light reactivity and variable relaxation kinetics.

The range of applications for photoswitching moieties is diverse, and the ability to design switches with variable photochemical and physical properties is consequently important for realizing their potential. Previously we reported on the photochromism of (E)-N'-(1-(2-hydroxyphenyl)ethylidene)isonicotinohydrazide (HAPI), an aroylhydrazone compound first developed as a transition metal chelator. Herein we report the synthesis of structurally related aroylhydrazone chelators and explore the effect of these modifications on their UVA, UVC and blue light photoreactivity, photostationary state composition, photoisomer thermal stability, and relative iron(iii) binding affinity. These findings will inform the next generation of aroylhydrazone photoswitches for metal-gated photoswitching applications.