Spin-controlled enantioselective near-infrared photocatalysis with chiral MgO/Co₃O₄ nanoparticles

Herein, we report D-/L-penicillamine-mediated magnesium oxide-doped cobalt oxide nanoparticles that exhibit strong mirror-image circular dichroism signals ( ~ 102 mdeg at ~800 nm) and function as effective near-infrared-driven photocatalysts for the enantioselective hydroxylation of tyrosine to dihydroxyphenylalanine. The D-nanoparticles demonstrated pronounced enantioselectivity, consuming 92.48% of L-tyrosine versus only 53.85% of D-tyrosine. Magnesium incorporation proves essential, increasing catalytic activity by 22.78 percentage points relative to undoped cobalt oxide nanoparticles. Mechanistically, Mg incorporation modulates the electronic structure to induce surface oxygen vacancies, which act as electron bridges to facilitate oxygen activation, significantly lowering the reaction barrier. Molecular dynamics simulations further unveil an inverse affinity-activity relationship, where heterochiral pairs enable efficient catalytic turnover through weaker, transient single hydrogen bonds, whereas high-affinity homochiral pairs are sequestered in non-productive states via rigid dual hydrogen bonds. This work establishes a distinct paradigm for rational catalyst design, balancing binding affinity with catalytic mobility.