Environmental significance of PAH photoproduct formation: TiO nanoparticle influence, altered bioavailability, and potential photochemical mechanisms.

Interactions between polycyclic aromatic hydrocarbons (PAHs) and titanium dioxide (TiO) nanoparticles (NPs) can produce unforeseen photoproducts in the aqueous phase. Both PAHs and TiO-NPs are well-studied and highly persistent environmental pollutants, but the consequences of PAH-TiO-NP interactions are rarely explored. We investigated PAH photoproduct formation over time for benzo[a]pyrene (BaP), fluoranthene (FLT), and pyrene (PYR) in the presence of ultraviolet A (UVA) using a combination of analytical and computational methods including, identification of PAH photoproducts, assessment of expression profiles for gene indicators of PAH metabolism, and computational evaluation of the reaction mechanisms through which certain photoproducts might be formed.

Time-Related Alteration of Aqueous-Phase Anthracene and Phenanthrene Photoproducts in the Presence of TiO Nanoparticles.

Polycyclic aromatic hydrocarbons (PAHs) and titanium dioxide (TiO) nanoparticles (NPs) are photoactive environmental pollutants that can contaminate aquatic environments. Aqueous-phase interactions between PAHs and TiO-NPs are of interest due to their emerging environmental relevance, particularly with the deliberate application of TiO-NPs to remediate pollution events (e.g.

Novel intramolecular C-H bond activation in an iridium dppm complex.

Reaction of TpIr(C(2)H(4))(2) (Tp = tris-pyrazolylborate) with various chelating phosphine ligands has been explored. Reaction with bis-diphenylphosphinoethane leads to complete displacement of the Tp ligand. With bis-diphenylphosphinomethane, an intramolecular proton transfer from the methylene bridge to the iridium center occurs to give an iridium hydride complex formally resulting from oxidative C-H bond activation.