Interplay of monomer, intra- and intermolecular excimer fluorescence in cyclophanes and selective recognition of methanol vapours

Mechanoresponsive luminescence and liquid-crystalline behaviour of a cyclophane featuring two 1,6-bis(phenylethynyl)pyrene groups

“…In 2013, Ramaiah's group reported that an anthracene-based cyclophane exhibits a photoluminescent colour change in the solid state when exposed to methanol vapour. 9 Our group also demonstrated that the photophysical properties of anthracenebased luminescent cyclophanes are controlled by thermal and mechanical stimuli in the solid states. 10 Our cyclophanes have two 9,10-bis(phenylethynyl)anthracene groups that are bridged by tetraethyleneglycol 10a or hexaethyleneglycol 10b linkers.…”

Linearly polarized photoluminescence from an asymmetric cyclophane showing thermo- and mechanoresponsive luminescence

“…Luminescent cyclophanes are intriguing compounds as they may exhibit unconventional photophysical functions that have never been achieved with the acyclic compounds. [10][11][12] The cyclic structure disturbs the ordered and close-molecular packing, which results in the formation of liquid-crystalline (LC) phases over wide temperature ranges. Even though a number of cyclophanes have been reported to show LC phases, 13,14 their luminescent properties remain unexplored.…”

Tuning the thermo- and mechanoresponsive behavior of luminescent cyclophanes

“…The linear compound 2 featuring the same luminophore was also synthesized for reference purposes. Compounds 1 and 2 were characterized by 1 H NMR, 13 C NMR, MALDI-TOF-MS spectra, and elemental analysis (see ESI †). We found that compound 1 dissolves well in chloroform, dichloromethane, tetrahydrofuran, and N,N-dimethylformamide, whereas hot chloroform was needed to dissolve the previously reported cyclophane 3.…”

“…1 H NMR spectra were recorded on a JEOL JNM-ECX 400 spectrometer and all chemical shis are quoted on the d-scale in ppm relative to the signal of tetramethylsilane (at 0.00) as an internal standard. Protondecoupled 13 C NMR spectra were recorded on a JEOL JNM-ECX 400 spectrometer and all chemical shis (d) are reported in ppm using residual solvent as the internal standard (CDCl 3 at 77.16). Coupling constants (J) are reported in Hz and relative intensities are also shown.…”

“…6e,8-11 As a result, most studies on luminescent cyclophanes have focused on their investigation in solution, while their solid-state properties have remained little examined. 13,14 Many compounds have been reported to display thermo-and mechanoresponsive luminescence characteristics, and which are possibly useful as sensing materials, in storage devices, and for security applications. [15][16][17][18][19][20] In many cases, a stimuli-induced re-arrangement of the molecular assembly is the cause for the observed changes of the photoluminescence, because the photophysical properties oen strongly depend on the molecular arrangement in the solid state.…”