Cocktails of Tb3+ and Eu3+ Complexes: A General Platform for the Design of Ratiometric Optical Probes
摘要:
Fluorescent and luminescent reporters that signal molecular events of interest by modulating the ratio of peaks in their emission profile have advantages over reporters that simply modulate their emission intensity, since ratiometric measurement is concentration-independent and allows them to be effective in complex contexts, such as living cells or sensor microarrays. We herein describe a general platform for the design of ratiometric probes based on a heterometallic Tb3+/Eu3+ bis-lanthanide ensemble, consisting of a mixture, or "cocktail", of otherwise identical heterometalated chelates. The chelate contains an organic photon antenna that sensitizes the Tb3+/Eu3+ luminescence. The contributions of the two metals to the composite luminescence spectrum can be tuned to the same relative scale by adjusting the stoichiometry of the cocktail, allowing subtle changes in their ratio to be accurately measured. Importantly, the ratio responds to chemical and environmental changes experienced by the photon antenna, making the system an ideal platform for the design of chemical and enzymatic probes. As proofs of concept, we describe a ratiometric probe for esterase activity and a polarity-responsive ratiometric sensor.
Intermolecular Energy Transfer from Tb3+ to Eu3+ in Aqueous Aggregates and on the Surface of Human Cells
摘要:
Efficient intermolecular energy transfer from carbostyril 124-sensitized Tb3+ to Eu3+ in aqueous aggregates is reported. This energy transfer was also recapitulated on the cell surface of a human kidney cell line (HEK-293T) and imaged by fluorescence microscopy as an example for the applicability of this energy transfer probe for imaging in biological systems.
Copper nanoparticles (CuNPs) catalyzed chemoselective reduction of nitroarenes in aqueous medium
作者:Randhir Rai、Dillip Kumar Chand
DOI:10.1007/s12039-021-01940-3
日期:2021.9
established, under appropriate reaction conditions, using rice (Oryza sativa) as an economic source of reducing as well as a stabilizing agent. Optical and microscopic techniques are employed for the characterization of the synthesized CuNPs and the sizes of the particles were found to be in the range of 8 ± 2 nm. The nanoparticles are used as a catalyst for chemoselective reduction of aromaticnitro compounds
Assisted tandem catalytic RCM-aromatization in the synthesis of pyrroles and furans
作者:Bernd Schmidt、Stefan Krehl、Eric Jablowski
DOI:10.1039/c2ob25543j
日期:——
An assisted tandem catalytic transformation of diallyl amines and diallyl ethers into N-aryl pyrroles and furans, respectively, is described. The sequence relies on ring closing metathesis followed by dehydrogenation of the initially formed dihydropyrroles and dihydrofurans. Both steps are Ru-catalyzed, but the sequence requires only one precatalyst, because conversion of the metathesis catalyst into
An efficient aerobicreduction of olefins, internal as well as terminal, is developed using guanidine as an organocatalyst. A remarkable chemoselectivity in reduction has been demonstrated in the presence of a variety of functional groups and protective groups and a selective reduction of a terminal olefin in the presence of an internal olefin is revealed.
A Phosphine-Mediated Dearomative Skeletal Rearrangement of Dianiline Squaraine Dyes
作者:Emily P. Bacher、Kevin J. Koh、Antonio J. Lepore、Allen G. Oliver、Olaf Wiest、Brandon L. Ashfeld
DOI:10.1021/acs.orglett.1c00248
日期:2021.4.16
A phosphorus(III)-mediated dearomatization of ortho-substituted dianiline squaraine dyes results in an unusual skeletalrearrangement to provide exotic, highly conjugated benzofuranone and oxindole scaffolds bearing a C3 side chain comprised of a linear conflagration of an enol, a phosphorus ylide, and 2,4-disubstituted aniline. Employing experimental and computational analysis, a mechanistic evaluation
Synthesis of Pyrrole Derivatives from Diallylamines by One-Pot Tandem Ring-Closing Metathesis and Metal-Catalyzed Oxidative Dehydrogenation
作者:Weiqiang Chen、Jianhui Wang
DOI:10.1021/om400046r
日期:2013.3.25
A series of aryl-substituted pyrrole derivatives was synthesized from diallylamines through a ruthenium carbene catalyzed ring-closingmetathesis reaction and in situ oxidative dehydrogenation reaction catalyzed by FeCl3·6H2O or CuCl2·2H2O in the presence of O2. The reaction was mild, simple, and convenient. An oxygen atmosphere played a critical role in obtaining high conversion of substituted pyrroles