Designing Efficient Solar-Thermal Fuels with [<i>n</i>.<i>n</i>](9,10)Anthracene Cyclophanes: A Theoretical Perspective

Molecular solar thermal storage (MOST) systems have been largely limited to three classes of molecular motifs: azo-benzene, norbornadiene, and transition metal based fulvalene-tetracarbonyl systems. Photodimerization of anthracene has been known for a century; however, this photoprocess has not been successfully exploited for MOST purposes due to its poor energy storage. Using well-calibrated theoretical methods on a series of [<i>n</i>.<i>n</i>]­(9,10)­bis-anthracene cyclophanes, we have exposed that they can store solar energy into chemical bonds and can release in the form of heat energy on demand under mild conditions. The storage is mainly attributed to the strain in the rings formed by the alkyl linkers upon photoexcitation. Our results demonstrate that the gravimetric energy storage density for longer alkyl-chain linkers (<i>n</i> > 3) are comparable to those for the best-known candidates; however, it lacks some of the deleterious attributes of known systems, thus making the proposed molecules desirable targets for MOST applications

Photochemical Hydrogenation of CO₂ to CH₃OH and Pyridine to 1,2-Dihydropyridine Using Plasmon-Facilitated Chemisorbed Hydrogen on Au Surface: Theoretical Perspective

CO₂ hydrogenation to methanol, a renewable fuel, under benign conditions and without the use of sacrificial agents is a rarity and certainly a much sought after goal of present-day research. Herein, we report using well calibrated computational tools the viability of hydrogenating CO₂ to CH₃OH and pyridine to 1,2-dihydropyridine, a renewable organohydride which can also reduce CO₂ to CH₃OH sustainably, using hydrogens chemisorbed on Au(111) surface of Au₂₀ by photo-excitation. Our studies predict that these hydrogenations can occur at appreciable rates at room temperature. Thus, we reveal the untapped potential of the chemisorbed hydrogens on Au(111) surface, achieved by hot-electron generation through photo-excitation, in facilitating endoergic hydrogenations akin to those enabled by NADPH