Controllable multicolor switching of oligopeptide-based mechanochromic molecules: from gel phase to solid powder

摘要: A series of molecules with pyrene and rhodamine B as color-producing mechanophores linked by different spacers were synthesized their mechanochromic properties studied. Interestingly, we found that the molecule diphenylalanine a linker (PHE-2) showed sequential multicolored switch from deep blue to bluish green further reddish color, which was associated phase change gel xerogel solvent evaporated, solid powder triggered grinding. However, pentaphenylalanine (PHE-5) exhibited same color switched virtue continuously grinding sample in situ. The switching PHE-2 PHE-5 realized variation self-assembled structures, induced transition excimers excimer 1 (deep blue) 2 (bluish green), chemical reaction spirolactam ring-opened amide (red). From experimental results, may conclude crucial point for controlling tuning tricolored fluorescent this system is constrict an overlapped packing mode, can be achieved (1) molecular structure; (2) confining restricted environment.