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201.
Ying Zhao Emma Rostal Sørensen Thomas Toft Lindkvist Dr. Christina Kjær Prof. Mogens Brøndsted Nielsen Prof. Li Chen Prof. Steen Brøndsted Nielsen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(42):10875-10882
When ionic dyes are close together, the internal Coulomb interaction may affect their photophysics and the energy-transfer efficiency. To explore this, we have prepared triangular architectures of three rhodamines connected to a central triethynylbenzene unit (1,3,5-tris(buta-1,3-diyn-1-yl)benzene) based on acetylenic coupling reactions and measured fluorescence spectra of the isolated, triply charged ions in vacuo. We find from comparisons with previously reported monomer and dimer spectra that while polarization of the π-system causes redshifted emission, the separation between the rhodamines is too large for a Stark shift. This picture is supported by electrostatic calculations on model systems composed of three linear and polarizable ionic dyes in D3h configuration: The electric field that each dye experiences from the other two is too small to induce a dipole moment, both in the ground and the excited state. In the case of heterotrimers that contain either two rhodamine 575 (R575) and one R640 or one R575 and two R640, emission is almost purely from R640 although the polarization of the π-system expectedly diminishes the dipole-dipole interaction. 相似文献
202.
Iben Skovsen Mogens Christensen Henrik Fanoe Clausen Jacob Overgaard Christian Stiewe Titas Desgupta Eckhard Mueller Mark A. Spackman Bo B. Iversen 《ChemInform》2010,41(51):no-no
Hexagonal CeMnNi4 is synthesized by high‐frequency induction melting of stoichiometric amounts of the elements with subsequent Czochralski crystal pulling. 相似文献
203.
Julius Seumer Jonathan Kirschner Solberg Hansen Mogens Brøndsted Nielsen Jan H. Jensen 《Angewandte Chemie (International ed. in English)》2023,62(18):e202218565
We present a de novo discovery of an efficient catalyst of the Morita–Baylis–Hillman (MBH) reaction by searching chemical space for molecules that lower the estimated barrier of the rate-determining step using a genetic algorithm (GA) starting from randomly selected tertiary amines. We identify 435 candidates, virtually all of which contain an azetidine N as the catalytically active site, which is discovered by the GA. Two molecules are selected for further study based on their predicted synthetic accessibility and have predicted rate-determining barriers that are lower than that of a known catalyst. Azetidines have not been used as catalysts for the MBH reaction. One suggested azetidine is successfully synthesized and showed an eightfold increase in activity over a commonly used catalyst. We believe this is the first experimentally verified de novo discovery of an efficient catalyst using a generative model. 相似文献
204.
205.
Dr. Esmeralda Bukuroshi Dr. Anne Ugleholdt Petersen Cecilie Jensen Mathias Kirkholt Lund Dr. Martin Kühnel Prof. Dr. Kasper Nørgaard Prof. Dr. Timothy P. Bender Prof. Dr. Mogens Brøndsted Nielsen 《European journal of organic chemistry》2023,26(24):e202300284
In this work, we have linked the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo-/thermoswitch and the boron subphthalocyanine (BsubPc) fluorophore via an axial oligo(phenyleneethynylene) bridging unit into new DHA-BsubPc conjugates. The objectives were to elucidate the influence of BsubPc on the DHA/VHF switching reactions and the influence of DHA/VHF on the BsubPc fluorescence in these conjugates for which the entire axial substituent connected to boron comprises one large, conjugated scaffold. We present the synthesis and properties of DHA-BsubPc conjugates with varying peripheral substituents on the BsubPc core, being either unsubstituted (H12BsubPc) or partially fluorinated (F6BsubPc). Fluorination of the BsubPc core provided a remarkable increase in the reversibility of the DHA-VHF interconversions promoted by light and heat, respectively, and accompanied by on/off switching of the BsubPc fluorescence. Synthetically, the units were connected using Sonogashira coupling reactions of suitable acetylenic building blocks. 相似文献