7 research outputs found
Adaptive synchronization in delay-coupled networks of Stuart-Landau oscillators
We consider networks of delay-coupled Stuart-Landau oscillators. In these
systems, the coupling phase has been found to be a crucial control parameter.
By proper choice of this parameter one can switch between different synchronous
oscillatory states of the network. Applying the speed-gradient method, we
derive an adaptive algorithm for an automatic adjustment of the coupling phase
such that a desired state can be selected from an otherwise multistable regime.
We propose goal functions based on both the difference of the oscillators and a
generalized order parameter and demonstrate that the speed-gradient method
allows one to find appropriate coupling phases with which different states of
synchronization, e.g., in-phase oscillation, splay or various cluster states,
can be selected.Comment: 8 pages, 7 figure
Controlling cluster synchronization by adapting the topology
We suggest an adaptive control scheme for the control of zero-lag and cluster
synchronization in delay-coupled networks. Based on the speed-gradient method,
our scheme adapts the topology of a network such that the target state is
realized. It is robust towards different initial condition as well as changes
in the coupling parameters. The emerging topology is characterized by a
delicate interplay of excitatory and inhibitory links leading to the
stabilization of the desired cluster state. As a crucial parameter determining
this interplay we identify the delay time. Furthermore, we show how to
construct networks such that they exhibit not only a given cluster state but
also with a given oscillation frequency. We apply our method to coupled
Stuart-Landau oscillators, a paradigmatic normal form that naturally arises in
an expansion of systems close to a Hopf bifurcation. The successful and robust
control of this generic model opens up possible applications in a wide range of
systems in physics, chemistry, technology, and life science
C,N-chelated diaminocarbene platinum(II) complexes derived from 3,4-diaryl-1H-pyrrol-2,5-diimines and cis-dichlorobis(isonitrile)platinum(II):Synthesis, cytotoxicity, and catalytic activity in hydrosilylation reactions
The reaction of 3,4-diaryl-1H-pyrrol-2,5-diimines with cis-dichlorobis(isonitrile)platinum(II) affords the C,N-chelated diaminocarbene platinum(II) complexes, which have been fully characterized including molecular spectroscopy, single crystal X-ray diffraction and DFT calculations. The obtained platinum(II) complexes are effective catalysts for the hydrosilylation of alkynes and alkenes. Thus, the reaction of phenylacetylene with triethoxysilane leads to the formation of α- and β-(E)-vinylsilanes, generating TON's in the range of 103 to 104 and TOF's in the range of 102 to 103 h−1. Also, the cross-linked silicones, possessing the luminescence properties, were obtained by the hydrosilylation reaction of vinyl- and hydride-containing polysiloxanes. Additionally, the efficiency of diaminocarbene platinum(II) complexes against CH1/PA-1, SW480, and A549 cancer cell lines has been demonstrated by in vitro cytotoxicity studies.peerReviewe
11<i>H</i>-Benzo[4,5]imidazo[1,2-<i>a</i>]indol-11-one as a New Precursor of Azomethine Ylides: 1,3-Dipolar Cycloaddition Reactions with Cyclopropenes and Maleimides
The possibility of generating azomethine ylides from 11H-benzo[4,5]imidazo[1,2-a]indol-11-one and amino acids is shown for the first time. Based on the cycloaddition reactions of these azomethine ylides with cyclopropenes and maleimides, cyclopropa[a]pyrrolizines, 3-azabicyclo[3.1.0]hexanes, and pyrrolo[3,4-a]pyrrolizines spiro-fused with a benzo[4,5]imidazo[1,2-a]indole fragment were synthesized. Spirocyclic compounds were obtained in moderate to good yields, albeit with poor diastereoselectivity. Density functional theory calculations were performed to obtain an insight into the mechanism of the 1,3-dipolar cycloaddition of 11H-benzo[4,5]imidazo[1,2-a]indol-11-one-derived azomethine ylides to cyclopropenes. The cytotoxic activity of some of the obtained cycloadducts against the human erythroleukemia (K562) cell line was evaluated in vitro by MTS-assay
CCDC 1983029: Experimental Crystal Structure Determination
Related Article: Anastasiia M. Afanasenko, Tatiana G. Chulkova, Irina A. Boyarskaya, Regina M. Islamova, Anton A. Legin, Bernhard K. Keppler, Stanislav I. Selivanov, Anatoly N. Vereshchagin, Michail N. Elinson, Matti Haukka|2020|J.Organomet.Chem.|923|121435|doi:10.1016/j.jorganchem.2020.12143