Supramolecular Interactions‐Assisted Polymorphism and Unique Mechanofluorochromism in 9,10‐Bis((E)‐4‐(trifluoromethyl)styryl)anthracene

Abstract

A fluorinated distyrylanthracene (DSA) derivative, 9, 10-bis((E)-4-(trifluoromethyl)styryl)anthracene abbreviated as 4FDSA with two crystalline polymorphs (4FDSA-G (green emission) and 4FDSA-O (orange emission)), showing remarkable aggregation-induced enhanced emission and mechanofluorochromic characteristics, was developed. One of the polymorphs in its crystalline arrangement exhibits the hardly seen F…F interactions. It questions the conventional belief of the non-polarisable nature of fluorine atoms in forming the halogen bond. The twisted molecular conformation facilitated by the various supramolecular interactions resulted in the formation of another intensely emissive bluer nanocrystal (4FDSA-NC) at aggregating conditions. Even though, the both polymorphs show distinct tricolor luminescence switching on the action of mechanical force, fumigation of ground crystals with solvent vapor resulted in the formation of a more thermodynamically favorable 4FDSA-NC form. The work demonstrates the effect of supramolecular interactions assisted conformational changes in tuning the unique mechanofluorochromic characteristics of the polymorphic crystals.

Translating efficient fluorescence into persistent room-temperature phosphorescence by doping bipolar fluorophores into polar polymer matrix

“…As reported, bipolar fluorophores with planar structures emit stronger fluorescence in high polarity solvents than in nonpolar solvents. [45][46][47][48] Accordingly, 7-AMCum molecules could generate more singlet excitons in highly polar PAA, PVA and PAN solid matrices. The dipole-dipole interactions between 7-AMCum and the polar hosts could reduce the energy level of low-lying singlet states; thus, the decreased DE ST facilitated SOCT-ISC.…”

Mechanofluorochromic Properties of 1,4-Diphenylanthracene Derivatives with Hypsochromic Shift

“…On the other hand, slightly longer fluorescence lifetimes (4.69–5.22 ns) were observed for the green luminous crystals ( 1e , 4 ). Additionally, much longer fluorescence lifetimes (7.39–109 ns) were observed for the yellow-green luminous crystals ( 1f , 2 , 3 ), and these greenish emission bands are probably due to the excimer emission of the diphenylanthracene part [ 47 , 48 , 51 , 61 , 62 , 63 , 64 , 65 ].…”

“…Mechanofluorochromic materials, which are solid organic light-emitting materials that change their luminous color upon mechanical stimuli by crushing or grinding, have attracted attention for their applications in security inks, memory chips, and pressure sensors [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. Numerous organic mechanofluorochromic materials have been reported, including metal complexes [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ], anthracene derivatives [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ], pyrene derivatives [ 66 , 67 , 68 , 69 , 70 ,…”

Symphony of light: AIE and MFC in carbazole-based cyanostilbenes

“…Recently, in 2023, Suneesh et al created a series of 9-butyl-9Hcarbazole derivatives 85 that exhibit strong solid-state emission with -CF 3 groups at various substituent positions of the phenyl group 21a-d, which have no, ortho, meta and para trifluoromethyl substitution, respectively (Fig. 15).…”