Confinement-controlled selective CO2 insertion into a dicopper dihydride core: A multiscale mechanistic study

Area of Science:

• * Inorganic Chemistry
• * Materials Science
• * Computational Chemistry

Background:

• * Carbon dioxide (CO2) is a crucial C1 feedstock for synthesizing fuels and chemicals.
• * Previous work showed CO2 insertion into a [Cu2H2] core via solid-gas reaction, forming unstable formate species.
• * Understanding crystal lattice effects on reactivity is key for designing new catalytic processes.

Purpose of the Study:

• * To elucidate the mechanism by which structural confinement enables selective CO2 insertion into a [Cu2H2] core.
• * To investigate the role of co-crystallized solvent molecules (tetrahydrofuran) in modulating reactivity.
• * To provide a computational framework for understanding crystal- vs. solution-phase reactivity differences.

Main Methods:

• * Multiscale computational approach combining molecular mechanics (MM) and hybrid quantum mechanics/molecular mechanics (QM/MM) molecular dynamics.
• * Enhanced-sampling free energy calculations to determine CO2 binding affinities and reaction pathways.
• * Analysis of site asymmetry induced by co-crystallized molecules.

Main Results:

• * Co-crystallized tetrahydrofuran induces site asymmetry around the [Cu2H2] core, affecting electronic environment and CO2 diffusion.
• * Site asymmetry significantly modulates CO2 binding affinities and dictates reaction pathways.
• * Demonstrated key differences between crystal- and solution-phase CO2 insertion and hydride transfer mechanisms.

Conclusions:

• * Crystal lattice confinement, specifically site asymmetry, is crucial for enabling selective CO2 insertion and stabilizing reactive intermediates.
• * The findings offer a generalizable framework for understanding how solid-state environments influence chemical reactivity.
• * This work provides mechanistic insights for designing catalysts that leverage lattice confinement for efficient CO2 utilization.