Surface-Radical Mobility Test by Self-Sorted Recombination: Symmetrical Product upon Recombination (SPR).

We describe here a study of the mobility of the alkoxy radical on a surface by detection of its recombination product. A novel method called symmetrical product recombination (SRP) uses an unsymmetrical peroxide that upon sensitized homolysis recombines to a symmetrical product [R'OOR → R'O↑ + OR → ROOR]. This allows for self-sorting of the radical to enhance the recombination path to a symmetrical product, which has been used to deduce surface migratory aptitude.

Superhydrophobic Surfaces as a Source of Airborne Singlet Oxygen through Free Space for Photodynamic Therapy.

A superhydrophobic (SH) sandwich system has been developed to enable "contact-free" airborne singlet oxygen (O) delivery to a water droplet. The contact-free feature means that the sensitizer is physically separated from the droplet, which presents opportunities for photodynamic therapy (PDT). Trapping of airborne O in a HO droplet residing on a lower SH surface was monitored with 9,10-anthracene dipropionate dianion by varying distances to an upper O-generating surface.

Dark-Binding Process Relevant to Preventing Photosensitized Oxidation: Conformation-Dependent Light and Dark Mechanisms by a Dual-Functioning Diketone.

Few photosensitizers function in both light and dark processes as they usually have no function when the lights are turned off. We hypothesized that light and dark mechanisms in an α-diketone will be decoupled by dihedral rotation in a conformation-dependent binding process. Successful decoupling of these two functions is now shown.

S,S-Chiral Linker Induced U Shape with a Syn-facial Sensitizer and Photocleavable Ethene Group.

There is a major need for light-activated materials for the release of sensitizers and drugs. Considering the success of chiral columns for the separation of enantiomer drugs, we synthesized an S,S-chiral linker system covalently attached to silica with a sensitizer ethene near the silica surface. First, the silica surface was modified to be aromatic rich, by replacing 70% of the surface groups with (3-phenoxypropyl)silane.

Kinetic Control in the Regioselective Alkylation of Pterin Sensitizers: A Synthetic, Photochemical, and Theoretical Study.

Alkylation patterns and excited-state properties of pterins were examined both experimentally and theoretically. 2D NMR spectroscopy was used to characterize the pterin derivatives, revealing undoubtedly that the decyl chains were coupled to either the O4 or N3 sites on the pterin. At a temperature of 70°C, the pterin alkylation regioselectively favored the O4 over the N3.