Filtern
Dokumenttyp
Sprache
- Englisch (3)
Referierte Publikation
- ja (3)
Schlagworte
- Catalytic oxidation (1)
- Coupling reactions (1)
- Eu diketonate (1)
- Explosion (1)
- FRET system (1)
- Feedstocks (1)
- Hydroxylation (1)
- Intensity method (1)
- Lifetime method (1)
- Luminescence (1)
A strongly fluorescent organic semiconducting polymer doped with a highly
temperature dependent fluorescent europium(III) complex is converted into a
nanosized material that is capable of optically sensing temperature (T) in the
range from 0 to 50 °C via two-photon excitation at 720 nm. The nanosensors
are prepared from a blue-fluorescent polyfluorene that acts as both a lightharvesting
antenna (to capture two-photon energy) and an energy donor in a
fluorescence resonance energy transfer (FRET) system. The photonic energy
absorbed by the polymer is transferred to the T-sensitive red-luminescent
europium complex contained in the nanoparticles. The close spatial proximity
of the donor and the acceptor warrants efficient FRET. A poly(ethylene glycol)-
co-poly(propylene oxide) block copolymer is also added to render the particles
biocompatible. It is shown that T can be calculated from a) the intensity of
the luminescence of the europium complex, b) the ratio of the intensities of
the red and blue luminescence, or c) the T-dependent luminescence lifetime
of the Eu(III) complex.
Europium 1,3-di(thienyl)propane-1,3-diones with outstanding properties for temperature sensing
(2015)
The synthesis of novel Eu complexes with 1,3-di(thienyl)propane-1,3-diones as ligands as well as their luminescence properties in different polymers are reported. The new temperature sensitive paints (TSPs) exhibit not only exceptional high temperature sensitivity over a wide range of temperatures but are also characterized by negligible pressure sensitivity and marked photostability. This is why they are outstandingly suitable for applications, e.g. in aerodynamics and hydrodynamics.
Although catalytic reductions, cross-couplings, metathesis, and oxidation of C=C double bonds are well established, the corresponding catalytic hydroxylations of C–H bonds in alkanes, arenes, or benzylic (allylic) positions, particularly with O2, the cheapest, 'greenest', and most abundant oxidant, are severely lacking. Certainly, some promising examples in homogenous and heterogenous catalysis exist, as well as enzymes that can perform catalytic aerobic oxidations on various substrates, but these have never achieved an industrial-scale, owing to a low space-time-yield and poor stability. This review illustrates recent advances in aerobic oxidation catalysis by discussing selected examples, and aims to stimulate further exciting work in this area. Theoretical work on catalyst precursors, resting states, and elementary steps, as well as model reactions complemented by spectroscopic studies provide detailed insight into the molecular mechanisms of oxidation catalyses and pave the way for preparative applications. However, O2 also poses a safety hazard, especially when used for large scale reactions, therefore sophisticated methodologies have been developed to minimize these risks and to allow convenient transfer onto industrial scale.