Multi-stimuli responsive behavior by a simple donor-acceptor type acylhydrazone based crystal.

[Display omitted] • A novel acylhydrazone based molecule was designed and synthesized that exhibit bright solid state luminescence. • The crystals exhibit multi-stimuli responsive property such as, mechanochromic, thermochromic and vapochromic luminescence switching. • The crystals display fascinating macroscopic surface cracking, movements when 365 nm or 405 nm light is illuminated on the crystal surface. • The examples of such single molecular material that have capability to respond to multiple stimuli is extremely rare. In this manuscript, we report a novel diphenylamine-acylhydrazone based compound namely (E)-N'-(4-(diphenylamino)benzylidene)-4-hydroxybenzohydrazide (DPAhydrzOH) which showed multi-stimuli responsive behavior by displaying pronounced mechanochromic luminescence (MCL), thermochromic luminescence and photomechanical effect in solid state. Single crystal structure of the compound revealed that the molecule is tied with different types of H-bonding interactions. Detailed mechanistic study suggests that the MCL switching in solid crystal is rooted to the shear pressure induced structural rearrangement. The captivating photomechanical effect in the crystal was expressed in the form of cracking, small movement under 365 nm light due to photoinduced trans to cis isomerization in solid state. [ABSTRACT FROM AUTHOR]