Nonresonant Photons Catalyze Photodissociation of Phenol.

Phenol represents an ideal polyatomic system for demonstrating photon catalysis because of its large polarizability, well-characterized excited-state potential energy surfaces, and nonadiabatic dissociation dynamics. A nonresonant IR pulse (1064 nm) supplies a strong electric field (4 × 10 V/cm) during the photolysis of isolated phenol (CHOH) molecules to yield CHO + H near two known energetic thresholds: the S/S conical intersection and the S - S origin. H-atom speed distributions show marked changes in the relative contributions of dissociative pathways in both cases, compared to the absence of the nonresonant IR pulse.

Photon catalysis of deuterium iodide photodissociation.

A catalyst enhances a reaction pathway without itself being consumed or changed. Recently, there has been growing interest in the concept of "photon catalysis" in which nonresonant photons, which are neither absorbed nor scattered, promote reactions. The driving force behind this effect is the interaction between the strong electric field associated with a pulsed, focused laser and the polarizability of the reacting system.

Polypyrrole nanoparticles for tunable, pH-sensitive and sustained drug release.

We report the development of a generalized pH-sensitive drug delivery system that can release any charged drug preferentially at the pH range of interest. Our system is based on polypyrrole nanoparticles (PPy NPs), synthesized via a simple one-step microemulsion technique. These nanoparticles are highly monodisperse, stable in solution over the period of a month, and have good drug loading capacity (∼15 wt%).