Breaking the blue limit of non-conjugated hydrocarbons via multiple through-space interactions

Abstract The development of non-conjugated luminescent systems has innovated the traditional design strategy of through-bond conjugation (TBC) and inspired a deeper understanding on molecular photophysics. However, a challenge encountered by these non-conjugated structures is that the fluorescence of pure hydrocarbon systems is largely confined to the blue region (∼470 nm), raising the question of whether this is a fundamental limitation. Herein, we break this barrier by constructing a library of over 50 non-conjugated arylated alkenes via a binuclear nickel-catalyzed hydroarylation of allenes. It is disclosed that synergistic multiple through-space interactions (TSI) including molecular twisting-tuned intramolecular TSI combined with intermolecular TSI mediated by the double bonds of styrene unit are critical for achieving the ultralong-wavelength aggregation-induced emission of these non-conjugated structures. This enables tunable light emission from blue to yellow, orange, and remarkably, even to single-compound-based warm white light. Furthermore, strategic substitution extends the fluorescence into the deep-red region, with a tail reaching 900 nm. This work demonstrates that non-conjugated pure hydrocarbons can achieve a broad spectrum of colors, fundamentally advancing the understanding of the luminescence phenomenon of non-conjugated systems and providing a novel design strategy for luminescent materials beyond the traditional TBC paradigm.