Stilbenes are a compelling class of organic photoswitches
with
a high degree of tunability that sensitively depend on their environment.
In this study, we investigate the adsorption properties of 4-(N,N-dimethylamino)-4′-nitrostilbene
(DANS), a push–pull stilbene, on amorphous silica glass. Plane-wave
density functional theory (DFT) calculations are used to understand
how the trans and cis isomers of
DANS interact with the amorphous surface and which are the most preferred
modes of adsorption. Our calculations revealed that the O–H···O
hydrogen bonds between the nitro group and hydroxyl groups of the
silica surface dominate the intramolecular interaction. In addition
to hydrogen bonding, O–H···π interactions
with the aromatic ring and double bond play a critical role in adsorption,
whereas C–H···O interactions are present, but
contribute little. Therefore, both isomers of DANS favor parallel
orientations such that not only the functional groups but also the
aromatic parts can strongly interact with the glass surface.