Spiro-Structure: A Good Approach to Achieve Mechanoluminescence Property

Following the development of organic mechanoluminescence (ML) materials, molecular packing was proved as the key point to the emission process under an external force. In this text, with the introduction of spiro-(fluorene-9-9'-xanthene) (SFX) unit as the building block, the molecular packing of the resultant compound (BSFXA) was optimized with the interlaced mode, directly leading to the efficient ML effect. The key role of SFX with a spiro-structure can be further confirmed by the ML inactivity of reference compound BFA with the replacement of SFX unit by dimethyl fluorene (MeF), which provided a novel strategy to construct organic ML luminogens.