Diaminotriazine substituted diphenyl ether: reversible structural transformation and solvent dependent solid state fluorescence

Abstract

The effect of molecular shape and position of hydrogen bonding functionality in the solid state structural self-assembly was investigated using diaminotriazine substituted diphenyl ether based positional isomers (1–5). The molecular shape was modulated by changing diaminotriazine position that produced channel supramolecular structures in 1, 3 and 5. There exists a direct correlation between the molecular shape and three dimensional structures; more linear molecules resulted in close-packing whereas molecules with a labyrinthine topology formed a channel structure. Supramolecular aspects pertaining to the influence of solvent of crystallization in structure formation and reversible structural transformation in solid state were also explored. 1–5 exhibited tunable solid state fluorescence (λ_max = 437–496 nm) depending on the diaminotriazine substitutional position and 3 showed solvent-dependent solid state fluorescence. The present study describes the generation of a supramolecular channel structure with functional properties such as tunable fluorescence by varying the position of hydrogen bond functionality and solvent of crystallization.