2 research outputs found
Substituent-Dependent Photophysical Properties Due to the Thorpe–Ingold Effect on Foldings of Alternating Substituted Methylene–Diethynylbenzene Copolymers: A Comparison of Carbon versus Silicon Tethers
Alternating <i>tert</i>-butyl- and methyl-substituted
alkoxyÂmethylene–diethynylÂbenzene copolymers with
different degrees of polymerization and the corresponding dimers are
synthesized. The <i>tert</i>-butyl-substituted polymers
show prominent emissions around 350–400 owing to ground state
interactions between adjacent chromophores separated by a substituted
methylene group. The Thorpe–Ingold effect exerted by the bulky <i>tert</i>-butyl group would compress the bond angle at the methylene
tether and may alter the overall folding scaffold of the polymer.
The interactions between adjacent chromophores would be significantly
enhanced in these <i>tert</i>-butyl-substituted copolymers.
On the other hand, the corresponding less bulky, methyl-substituted
alkoxyÂmethylene tethered copolymers exhibit emission around
400–450 nm attributed to the through-space interactions between
nonadjacent diethynylÂbenzene chromophores. The variations of
folding nature of these two kinds of copolymers are determined by
the size of the substituents, methyl versus <i>tert</i>-butyl,
resulting in different photophysical behaviors. The emission properties
of the methyl-substituted copolymers behave similarly to those of
related silylene-tethered copolymers in the literatures, albeit the
relative intensity in the blue light emission is somewhat smaller
in methylene-bridged copolymers than in silylene-linked copolymers
A Rapid SNAP-Tag Fluorogenic Probe Based on an Environment-Sensitive Fluorophore for No-Wash Live Cell Imaging
One major limitation of labeling
proteins with synthetic fluorophores
is the high fluorescence background, which necessitates extensive
washing steps to remove unreacted fluorophores. In this paper, we
describe a novel fluorogenic probe based on an environment-sensitive
fluorophore for labeling with SNAP-tag proteins. The probe exhibits
dramatic fluorescence turn-on of 280-fold upon being labeled to SNAP-tag.
The major advantages of our fluorogenic probe are the dramatic fluorescence
turn-on, ease of synthesis, high selectivity, and rapid labeling with
SNAP-tag. No-wash labeling of both intracellular and cell surface
proteins was successfully achieved in living cells, and the localization
of these proteins was specifically visualized