Fluorescein Prototropism within Poly(ethylene glycol)s and Their Aqueous Mixtures

β-AlkenylBODIPY Dyes: Regioselective Synthesis via Oxidative C-H Olefination, Photophysical Properties, and Bioimaging Studies

A series of 2-alkenyl- and 2,6-dialkenylboron dipyrromethene (BODIPY) derivatives were synthesized through Pd(II)-catalyzed regioselective and stereoselective oxidative C-H olefination in one step. The 2-alkenyl BODIPY derivative further reacted with various amines regioselectively at the 5-position through direct oxidative nucleophilic substitution. The photophysical properties of the 2-alkenyl- and 2,6-dialkenyl-substituted BODIPYs were investigated, which showed great potential in fluorescent bioimaging.

Layered rare-earth hydroxide (LRH, R = Tb, Y) composites with fluorescein: delamination, tunable luminescence and application in chemosensoring for detecting Fe(iii) ions

We demonstrate a novel example of tunable luminescence and the application of the delaminated FLN/OS-LRH composites (LRHs are layered rare-earth hydroxides, R = Tb, Y; FLN is the fluorescein named 2-(6-hydroxy-3-oxo-(3H)-xanthen-9-yl)benzoic acid; OS is the anionic surfactant 1-octane sulfonic acid sodium) in detecting Fe(iii) ions. The FLNxOS1-x species (x = 0.02, 0.05, 0.10, and 0.20) are intercalated into the LTbyY1-yH layers (y = 1, 0.9, 0.7, 0.5, 0.3, 0.1 and 0) by ion exchange reactions to yield the composites FLNxOS1-x-LTbyY1-yH. In the solid state, the LYH composites display green emission (564 nm) arising from the organic FLN, while in LTbH composites, the luminescence of the Tb3+ in the layers (545 nm) and the FLN in the interlayers is co-quenched. In the delaminated state in formamide (FM), FLNxOS1-x-LTbH composites display green to yellowish-green luminescence (540-574 nm) following the increasing FLN/OS ratio; while the FLN0.02OS0.98-LTbyY1-yH composites show green emission at ∼540 nm. The fluorescence lifetimes of the composites (4.22-4.63 ns) are comparable to the free FLN-Na, and the quantum yields (31.62-78.70%) of the composites especially that (78.70%) of the FLN0.02OS0.98-LYH are much higher than that (28.40%) of free FLN-Na. The recognition ability of the FLN0.02OS0.98-LYH composite for metal cations is researched. The delaminated FLN0.02OS0.98-LYH colloidal suspension exhibits high selectivity for Fe3+ over other ions (Mg2+, Al3+, Ni2+, Co2+, Cu2+, Zn2+, Mn2+, Pb2+, and Cd2+) with fluorescence quenching, which can work as a kind of turn-off fluorescence sensor for the detection of Fe3+. The detection limit of Fe3+ is determined to be 2.58 × 10-8 M and the quenching constant (Ksv) is 1.70 × 103 M-1. This is the first work on LRH materials working as a chemosensor for recognising metal cations. It provides a new approach for the design of LRH materials to be applied in fluorescence chemosensing.

A visually detectable pH responsive zirconium metal–organic framework

A functionalized MOF, NU-1000–CNF, shows simultaneous hydrolysis of nerve agent simulants while visually sensing the acid byproducts produced.

Moleavin IA, Hurduc N, Hamel M, Rocha L. Fluorescent polymeric aggregates for selective response to Sarin surrogates

Fluorescent polymeric chemical sensors with double signal generation in aqueous solutions for Sarin detection.