Unveiling Orthogonal Mechanochemical Pathways via ¹⁹ F NMR under a Three-Arm Pulling Strategy

Polymer mechanochemistry enables control over the chemical reactivity through defined force-loading geometries. However, in most mechanophores, force is transmitted through only two loading points, which confines reactivity to a single dominant pathway and limits the diversity of mechanically accessible outcomes. Here, we report a fluorinated 1,2-diazetidinone-based mechanophore that enables the simultaneous activation of two orthogonal mechanochemical reaction pathways under a three-arm pulling geometry. Upon force application, parallel scission reactions occur within a single mechanophore scaffold, generating imine/isocyanate and azo/ketene products. Strategic incorporation of fluorine permits unambiguous identification and quantitative analysis of mechanically generated species by ¹⁹F NMR spectroscopy. Computational analysis reveals that pathway selectivity under three-arm pulling mirrors the relative reactivities observed under two-arm loading, with N¹-N² bond cleavage favored over C³-N² scission, while geometric constraints suppress interconversion between pathways. Together, these results establish multiarm force loading as a general strategy for accessing multiple, independent mechanochemical transformations within a single mechanophore, thereby expanding the conceptual and practical scope of force-responsive molecular design.