Solvent-Vapor-Induced Reversible Single-Crystal-to-Single-Crystal Transformation of a Triphosphaazatriangulene-Based Metal-Organic Framework

A triphosphaazatriangulene (H3L) was synthesized through an intramolecular triple phospha-Friedel-Crafts reaction. The H3L triangulene contains three phosphinate groups and an extended p-conjugated framework, which enables the stimuli-responsive reversible transformation of [Cu(HL)(DMSO)center dot(MeOH)]n, a 3D-MOF that exhibits reversible sorption characteristics, into (H3L center dot 0.5[Cu2(OH) 4 center dot 6H2O] center dot 4H2O), a 1D-columnar assembled proton-conducting material. The hydrophilic nature of the latter resulted in a proton conductivity of 5.5 103 Scm1 at 95% relative humidity and 60 degrees C.