Cation-anion interaction directed dual-mode switchable mechanochromic luminescence

摘要

In the past few years, organic mechanochromic materials have attracted more and more attention and a number of organic mechanochromic materials have been reported. However, only a single mode for switching of mechanochromic luminescence, either red-shift or blue-shift of the luminescence, can be observed for all the reported mechanochromic materials. Herein, based on a single tributyl(perylen-3-ylmethyl) phosphonium (TPMP) fluorophore, dramatic dual-mode switchable mechanochromic luminescence triggered by tunable cation-anion interactions has been reported for the first time. The trend of mechanochromic luminescence changes gradually from a red-shift to a blue-shift along with the strength order of the cation-anion interaction: Br- > 4 BF4- > PF6_ > NTf2-. A reversible transition of a crystalline state to an amorphous phase might be involved in the mechanochromic luminescence of TPMP.X (X = counteranion) with different counteranions.