Publications by authors named "H S Shafaat"
Developing photoactivated artificial enzymes for sustainable fuel production.
Curr Opin Chem Biol
December 2024
Enzymes catalyze molecular reactions with remarkable efficiency and selectivity under mild conditions. Photoactivated enzymes make use of a light-absorbing chromophore to drive chemical transformations, ideally using sunlight as an energy source. The direct attachment of a chromophore to native enzymes is advantageous, as information on the underlying catalytic mechanisms can be obtained.
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- The study focuses on using transition metals, specifically rhenium, to split nitrogen (N) and form metal nitride complexes, which could lead to efficient electrochemical nitrogen fixation to create ammonia under mild conditions.
- The proposed nitrogen fixation cycle involves binding N to form a complex, cleaving the N bridge, and then undergoing proton/electron transfer to produce ammonia, while a catalyst must fulfill specific electronic requirements during these processes.
- The introduction of an isocyanide ligand in the rhenium system helps facilitate electron reduction and protonation, increasing the stability of the process and enabling ammonia production, demonstrating how modifying supporting ligands can improve reactivity in synthetic cycles for nitrogen conversion.
Light-driven hydrogen evolution is a promising means of sustainable energy production to meet global energy demand. This study investigates the photocatalytic hydrogen evolution activity of nickel-substituted rubredoxin (NiRd), an artificial hydrogenase mimic, covalently attached to a ruthenium phototrigger (RuNiRd). By systematically modifying the para-substituents on Ru(II) polypyridyl complexes, we sought to optimize the intramolecular electron transfer processes within the RuNiRd system.
View Article and Find Full Text PDFHeme enzymes play a central role in a medley of reactivities within a wide variety of crucial biological systems. Their active sites are highly decorated with pivotal evolutionarily optimized non-covalent interactions that precisely choreograph their biological functionalities with specific regio-, stereo-, and chemo-selectivities. Gaining a clear comprehension of how such weak interactions within the active sites control reactivity offers powerful information to be implemented into the design of future therapeutic agents that target these heme enzymes.
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