posted on 2021-12-28, 19:18authored byNana Sun, Chiming Wang, Baoqiu Yu, Hailong Wang, Leonard J. Barbour, Jianzhuang Jiang
Responsive materials have received
much attention due to modulated
properties under stimuli such as light, heat, and electricity. A photoresponsive
porous molecular crystal (1) has been assembled from
a racemic dithienylethene-cage (L) by multiple C–F···H–C
hydrogen bonds and van der Waals forces according to crystallographic
investigation. Electronic absorption spectroscopy reveals reversible
photochromic behaviors of the solution and film forms of enantiomeric
L upon UV and visible light irradiation due to photoisomerization
of dithienylethene units. X-ray photoelectron spectroscopy (XPS),
in combination with NMR, discloses the quantitative photoisomerization
of photochromic dithienylethene moieties. Moreover, the porosity of 1 is modulated by UV irradiation based on gas sorption data.
Interestingly, heating the irradiated sample of 1 in
1,4-dioxane leads to recovered porosity due to the recovered cage
molecular structure and maintained periodic frameworks.