TY  - JOUR
A1  - Sawatzky, Edgar
A1  - Drakopoulos, Antonios
A1  - Rölz, Martin
A1  - Sotriffer, Christoph
A1  - Engels, Bernd
A1  - Decker, Michael
T1  - Experimental and theoretical investigations into the stability of cyclic aminals
JF  - Beilstein Journal of Organic Chemistry
N2  - Background: Cyclic aminals are core features of natural products, drug molecules and important synthetic intermediates. Despite their relevance, systematic investigations into their stability towards hydrolysis depending on the pH value are lacking.

Results: A set of cyclic aminals was synthesized and their stability quantified by kinetic measurements. Steric and electronic effects were investigated by choosing appropriate groups. Both molecular mechanics (MM) and density functional theory (DFT) based studies were applied to support and explain the results obtained. Rapid decomposition is observed in acidic aqueous media for all cyclic aminals which occurs as a reversible reaction. Electronic effects do not seem relevant with regard to stability, but the magnitude of the conformational energy of the ring system and pK a values of the N-3 nitrogen atom.

Conclusion: Cyclic aminals are stable compounds when not exposed to acidic media and their stability is mainly dependent on the conformational energy of the ring system. Therefore, for the preparation and work-up of these valuable synthetic intermediates and natural products, appropriate conditions have to be chosen and for application as drug molecules their sensitivity towards hydrolysis has to be taken into account.
KW  - quantum mechanics
KW  - hydrolysis
KW  - kinetics
KW  - molecular mechanics
KW  - natural products
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-160976
VL  - 12
ER  - 
TY  - JOUR
A1  - Jahnke, Frank
A1  - Gies, Christopher
A1  - Aßmann, Marc
A1  - Bayer, Manfred
A1  - Leymann, H.A.M.
A1  - Foerster, Alexander
A1  - Wiersig, Jan
A1  - Schneider, Christian
A1  - Kamp, Martin
A1  - Höfling, Sven
T1  - Giant photon bunching, superradiant pulse emission and excitation trapping in quantum-dot nanolasers
JF  - Nature Communications
N2  - Light is often characterized only by its classical properties, like intensity or coherence. When looking at its quantum properties, described by photon correlations, new information about the state of the matter generating the radiation can be revealed. In particular the difference between independent and entangled emitters, which is at the heart of quantum mechanics, can be made visible in the photon statistics of the emitted light. The well-studied phenomenon of superradiance occurs when quantum–mechanical correlations between the emitters are present. Notwithstanding, superradiance was previously demonstrated only in terms of classical light properties. Here, we provide the missing link between quantum correlations of the active material and photon correlations in the emitted radiation. We use the superradiance of quantum dots in a cavity-quantum electrodynamics laser to show a direct connection between superradiant pulse emission and distinctive changes in the photon correlation function. This directly demonstrates the importance of quantum–mechanical correlations and their transfer between carriers and photons in novel optoelectronic devices.
KW  - photon bunching
KW  - quantum mechanics
KW  - superradiant pulse emission
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166144
VL  - 7
IS  - 11540
ER  -