146
5 Mechanical-Stimulation-Triggered and Solvent-Vapor-Induced …
Fig. 5.14 1 H NMR spectra of 3G/MeOH and 3O, which are obtained by the recrystallization,
dissolved in CDCl 3
300
250
200
150
100
50
100
50
0
Weight/ %
Temperature / ºC
Heating rate: 5 ºC/min
Fig. 5.15 TGA profiles of 3O. The heating rate is 5 °C/min. There was no decrease in the weight
percent of the sample until ca. 150 °C. This result indicates that the 3O crystal does not include
solvent molecules
5.7.9 Changes of the Luminescence After Exposure
to External Stimuli
Crystals of 3 showed emission-color changes from green to orange upon gentle heating to 30 °C for 10 min under ambient conditions (Fig. 5.19a). The emission spectrum
of the resulting orange-emitting crystal (3O heat ) matched that of 3O scsc obtained from
cutting crystals of 3G/MeOH (Fig. 5.19c). Furthermore, crystals of 3O heat showed
a recovery of their initial green emission upon increasing the concentration of the
MeOH vapor (Fig. 5.19b). Crystals of 3O, obtained from recrystallization from
CH 2 Cl 2 and hexane, did not show a change of their emission upon being exposed to
high concentrations of MeOH vapor in a petri dish, or when liquid MeOH was added
directly (Figs. 5.19 and 5.20).
5 Mechanical-Stimulation-Triggered and Solvent-Vapor-Induced …
Fig. 5.14 1 H NMR spectra of 3G/MeOH and 3O, which are obtained by the recrystallization,
dissolved in CDCl 3
300
250
200
150
100
50
100
50
0
Weight/ %
Temperature / ºC
Heating rate: 5 ºC/min
Fig. 5.15 TGA profiles of 3O. The heating rate is 5 °C/min. There was no decrease in the weight
percent of the sample until ca. 150 °C. This result indicates that the 3O crystal does not include
solvent molecules
5.7.9 Changes of the Luminescence After Exposure
to External Stimuli
Crystals of 3 showed emission-color changes from green to orange upon gentle heating to 30 °C for 10 min under ambient conditions (Fig. 5.19a). The emission spectrum
of the resulting orange-emitting crystal (3O heat ) matched that of 3O scsc obtained from
cutting crystals of 3G/MeOH (Fig. 5.19c). Furthermore, crystals of 3O heat showed
a recovery of their initial green emission upon increasing the concentration of the
MeOH vapor (Fig. 5.19b). Crystals of 3O, obtained from recrystallization from
CH 2 Cl 2 and hexane, did not show a change of their emission upon being exposed to
high concentrations of MeOH vapor in a petri dish, or when liquid MeOH was added
directly (Figs. 5.19 and 5.20).