A survey of photogeochemistry

The participation of sunlight in the natural chemistry of the earth is presented as a unique field of study, from historical observations to prospects for future inquiry. A compilation of known reactions shows the extent of light-driven interactions between naturally occurring components of land, air, and water, and provides the backdrop for an outline of the mechanisms of these phenomena. Catalyzed reactions, uncatalyzed reactions, direct processes, and indirect processes all operate in natural photochemical transformations, many of which are analogous to well-known biological reactions. By overlaying photochemistry and surface geochemistry, complementary approaches can be adopted to identify natural photochemical reactions and discern their significance in the environment.

The Ruff degradation: a review of previously proposed mechanisms with evidence that the reaction proceeds by a Hofer-Moest-type reaction

The Ruff degradation reaction is critically reviewed. Based on available information, the Hofer-Moest decarboxylation mechanism is presented as the mechanism for it. Cu(III) is proposed as the active species of the copper variant of the Ruff degradation, which is the most efficient form of the reaction.