Mechanogated PINO radical organocatalysis: Catalytic amplification of mechanical force

The application of mechanical force to drive selective chemical transformations represents a central goal in polymer mechanochemistry, with mechanocatalysis emerging as a key strategy for achieving reaction amplification. Existing systems, however, are confined to ionic or coordination-based pathways, leaving the vast landscape of radical-mediated catalysis largely unexplored. Although sophisticated mechanophores can generate specific radical species, these intermediates have been limited to stoichiometric roles─as initiators, reporters, or reactants─rather than as participants in catalytic cycles. Herein, we introduce the concept of mechanogated radical organocatalysis to bridge this fundamental gap. We report the rational design of an N-benzhydryloxyphthalimide (PINO-DPM) mechanophore that, under ultrasonic activation, undergoes selective C-O bond cleavage to directly release the stable, catalytically competent phthalimide N-oxyl (PINO) radical. This species functions as a hydrogen-atom transfer catalyst for the aerobic oxidation of aldehydes with a turnover number exceeding 600─a direct quantitative measure of how a single bond-breaking event is amplified into sustained chemical output. This work thereby bridges the long-standing divide between force-activated radical generation and productive catalysis, opening new avenues for the development of force-responsive polymer materials with versatile functions.