Fluorescence Turn-On
Response Amplified by Space Confinement in Metal–Organic Frameworks
Xue-Mei Yin
Lu-Lu Gao
Peng Li
Ran Bu
Weng-Jie Sun
En-Qing Gao
10.1021/acsami.9b18307.s001
https://acs.figshare.com/articles/journal_contribution/Fluorescence_Turn-On_Response_Amplified_by_Space_Confinement_in_Metal_Organic_Frameworks/11310497
Sensitive fluorescence turn-on response to specific substances
is highly desired for development of chemical sensors and switches.
Here we utilized a “two-in-one” strategy to prepare
ionic metal–organic frameworks (MOFs) functionalized with the
cationic bipyridinium receptors at the frameworks and anionic fluorescent
indicators in the pores. The MOFs are rendered a fluorescence-resting
state because the indicator’s fluorescence is efficiently quenched
by the ground-state charge-transfer (CT) complexation between the
indicator and receptor. Addition of an alkylamine efficiently turns
on the fluorescence because the indicator is displaced by the CT complexation
between alkylamine with receptor. The turn-on response is highly specific
to alkylamines. The MOFs can be used as recyclable sensors for selective
and sensitive detection of alkylamines, with ultralow detection limits
(0.5 nM). The fluorescence in solid state can be reversibly switched
on and off with high contrast. The sensitive and high-contrast response
can be attributed to the space confinement effects of the porous frameworks.
The confined space can significantly enhance indicator–receptor
and analyte–receptor interactions, and thereby both the quenching
efficiency in the off state and the displacement efficiency in the
on state are amplified.
2019-12-03 15:24:06
detection
Fluorescence Turn-On Response Amplified
indicator
CT complexation
space confinement effects
fluorescence turn-on response
chemical sensors
quenching efficiency
high-contrast response
displacement efficiency
framework
turn-on response
Space Confinement
alkylamine
cationic bipyridinium receptors
fluorescence-resting state
ground-state charge-transfer
MOF