Cascading g-C₃N₄ and Peroxygenases for Selective Oxyfunctionalization Reactions

Abstract

Peroxygenases are very interesting catalysts for specific oxyfunctionalization chemistry. Instead of relying on complicated electron transport chains, they rely on simple hydrogen peroxide as the stoichiometric oxidant. Their poor robustness against H 2 O 2 can be addressed via in situ generation of H 2 O 2 . Here we report that simple graphitic carbon nitride (g-C 3 N 4 ) is a promising photocatalyst to drive peroxygenase-catalyzed hydroxylation reactions. The system has been characterized by outlining not only its scope but also its current limitations. In particular, spatial separation of the photocatalyst from the enzyme is shown as a solution to circumvent the undesired inactivation of the biocatalyst. Overall, very promising turnover numbers of the biocatalyst of more than 60.000 have been achieved.

Chromoselective Photocatalysis Enables Stereocomplementary Biocatalytic Pathways**

“…Without MeOH the same concentration of product was detected. Thus, the reaction is possible without a sacrificial electron donor like MeOH or formate, which is in contrast to some examples reported in literature [14a, 20] . For practical reasons, MeOH was still used since it simplified the preparation of stock solutions of the hydrophobic substrates.…”

Photo‐biocatalytic Cascades: Combining Chemical and Enzymatic Transformations Fueled by Light

“…Organic dyes, for instance, are prone to inactivation due to photobleaching [45,131–133] . QDs are often based on toxic heavy metals like cadmium which is unbeneficial for their implementation in environmental benign processes and carbon‐based nanoparticles such as g‐C 3 N 4 have been reported to bind to the biocatalyst or causes locally high concentrations of radicals which leads to the inactivation of the enzyme [134] …”

Applications of Nanomaterials in Asymmetric Photocatalysis: Recent Progress, Challenges, and Opportunities

“…It is worth mentioning that this semiconductor photocatalyst‐enzyme coupling strategy could also be extended to many other semiconductors with water oxidation activity like Au–BiVO 4 , carbon nanodot (CND) and graphitic carbon nitride (g‐C 3 N 4 ), etc. [ 44–47 ]…”