Luminescence modulation <i>via</i> solvent-triggered single-crystal-to-single-crystal transformation in a non-porous molecular crystal

Stimuli-responsive crystalline materials have demonstrated significant potential for developing multifunctional systems. Achieving precise structural modulation in non-porous crystalline phases remains a critical challenge, particularly in correlating molecular-level conformational changes with macroscopic properties. Here, we report a solvatomorphic crystalline system, (1-azabicyclo[2.2.2]octane-κN){4,4',6,6'-tetra-tert-butyl-2,2'-[1,2-phenylenebis(nitrilomethylidyne)]diphenolato-κ⁴O,N,N',O'}zinc(II) acetonitrile monosolvate, [Zn(C₃₆H₄₆N₂O₂)(C₇H₁₃N)]·CH₃CN or [Zn(saloph)](quinuclidine)](acetonitrile) (1·solvent), which exhibits a reversible single-crystal-to-single-crystal transformation during acetonitrile adsorption/desorption. Structure analysis reveals that solvation dynamics induce a pronounced variation in the dihedral angle of the [Zn(saloph)] coordination centre, accompanied by a luminescence red shift of approximately 10 nm. This work establishes a strategy for modulating optoelectronic properties in non-porous crystalline materials through solvent-mediated structural reorganization, advancing the development of stimuli-responsive functional materials.