No abstract

A set of strained aromatic macrocycles based on [n]cyclo‐2,7‐(4,5,9,10‐tetrahydro)pyrenylenes is presented with size‐dependent photophysical properties. The K‐region of pyrene was functionalized with ethylene glycol groups to decorate the outer rim and thereby confine the space inside the macrocycle. This confined space is especially pronounced for n=5, which leads to an internal binding of up to 8.0×104 m−1 between the ether‐decorated [5]cyclo‐2,7‐pyrenylene and shape‐complementary crown ether–cation complexes. Both the ether‐decorated [n]cyclo‐pyrenylenes as well as one of their host–guest complexes have been structurally characterized by single‐crystal X‐ray analysis. In combination with computational methods the structural and thermodynamic reasons for the exceptionally strong binding have been elucidated. The presented rim confinement strategy makes cycloparaphenylenes an attractive supramolecular host family with a favorable, size‐independent read‐out signature and binding capabilities extending beyond fullerene guests.

No abstract

Network virtualization (NV) has ubiquitously emerged as an indispensable attribute to enable the success of the forthcoming virtualized networks (eg, 5G network and smart Internet of Things [IoT]). Virtual network embedding (VNE) is the major challenge in NV that allows multiple heterogeneous virtual networks (VNs) to simultaneously coexist on a shared substrate infrastructure. A great number of VNE algorithms have been proposed, but over the past decades, most of them are only targeting for VNE node mapping. In this paper, we propose two distributed parallel genetic algorithms, which are based on two versions of crossover and mutation schemes, for online VN link embedding problems with low latency and high efficiency. Furthermore, we conduct a time analysis on the executing time of independently distributed parallel computing machines in details. This comprehensive analysis validates the parallel computing scalability on an identical number of predefined parallel machines. Extensive simulations have shown that our proposed algorithms can achieve better performance than integer linear programming (ILP)-based solutions while meeting the stringent time requirements for online VN embedding applications. Our proposed algorithms yield superior performance in running time with 32.78% up to 1727.8% faster than existing popular VNE algorithms. Additionally, the theoretical analysis indicates that the execution time can be reduced to logarithmic times by applying proposed distributed parallel algorithms.

Eine Reihe gespannter aromatischer Makrozyklen basierend auf [n]Cyclo‐2,7‐(4,5,9,10‐tetrahydro)pyrenylenen wurde an der K‐Region der Pyreneinheit mit Ethylenglykol‐Gruppen funktionalisiert, um im Innenraum des Makrozyklus eine definierte Bindungstasche zu formen. Diese ist für den fünfgliedrigen Makrozyklus besonders ausgeprägt, was zu einer Bindungskonstante von 8.0×104 m−1 zwischen dem Ether‐dekorierten [5]Cyclo‐2,7‐pyrenylen und einem komplementären Kronenether‐Kation‐Komplex führt. Die Ether‐dekorierten [n]Cyclopyrenylene sowie einer der Wirt‐Gast‐Komplexe wurden durch Kristallstrukturanalyse charakterisiert. In Kombination mit computergestützten Berechnungsmethoden wurden die strukturellen und thermodynamischen Hintergründe für die besonders starken nicht‐kovalenten Bindungseigenschaften erklärt. Die hier vorgestellte Strategie zur Formung von Bindungstaschen erschließt die Stoffklasse der Cycloparaphenylene als eine attraktive supramolekulare Wirt‐Familie, die größenunabhängige Ausleseparameter und Bindungseigenschaften über Fulleren‐Gäste hinaus zeigt.