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The first donor-stabilized tetrasilacyclobutadiene dication species has been synthesized and fully characterized. Its unexpected formation occurs by the Lewis acid assisted reaction of the N-heterocyclic chloro silylene [L(Si:)Cl] (L = PhC(NtBu)(2); amidinate) with Cp*ZrCl(3) (Cp* = pentamethylcyclopentadienyl) in the molar ratio of 3:2. Remarkably, the four-membered Si(4) core consists of two N-donor stabilized silylium subunits and two silylene-like moieties. The dicationic charge is somewhat delocalized on the Si(4) core, which is supported by DFT calculations. 相似文献
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The eigen frequencies of radial pulsations of neutron stars are calculated in a strong magnetic field. At low densities we
use the magnetic BPS equation of state (EOS) similar to that obtained by Lai and Shapiro while at high densities the EOS obtained
from the relativistic nuclear mean field theory is taken and extended to include strong magnetic field. It is found that magnetized
neutron stars support higher maximum mass whereas the effect of magnetic field on radial stability for observed neutron star
masses is minimal. 相似文献
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Jeroen Rintjema Roel Epping Dr. Giulia Fiorani Dr. Eddy Martín Eduardo C. Escudero‐Adán Prof. Dr. Arjan W. Kleij 《Angewandte Chemie (International ed. in English)》2016,55(12):3972-3976
Substituted epoxy alcohols and amines allow substrate‐controlled conversion of CO2 into a wide range of heterocyclic structures through different mechanistic manifolds. This new approach results in an unusual scope of CO2‐derived products by initial activation of CO2 through either the amine or alcohol unit, thus providing nucleophiles for intramolecular epoxy ring opening under mild reaction conditions. Control experiments support the crucial role of the amine/alcohol fragment in this process with the nucleophile‐assisted ring‐opening step following an SNi pathway, and a 5‐exo‐tet cyclization, thus leading to heterocyclic scaffolds. 相似文献
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Michaela König Dr. Massimo Rigo Nicolas Chaoui Trung Tran Ngoc Dr. Jan Dirk Epping Dr. Johannes Schmidt Dr. Pradip Pachfule Meng-Yang Ye Dr. Matthias Trunk Prof. Johannes F. Teichert Prof. Matthias Drieß Prof. Arne Thomas 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20002-20006
An iridium dihydride pincer complex [IrH2(POCOP)] is immobilized in a hydroxy-functionalized microporous polymer network using the concepts of surface organometallic chemistry. The introduction of this novel, truly innocent support with remote OH-groups enables the formation of isolated active metal sites embedded in a chemically robust and highly inert environment. The catalyst maintained high porosity and without prior activation exhibited efficacy in the gas phase hydrogenation of ethene and propene at room temperature and low pressure. The catalyst can be recycled for at least four times. 相似文献
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We present detailed investigations of a femtosecond green-pumped optical parametric oscillator (OPO) based on lithium triborate.
As pump source, a frequency-doubled Yb-fiber laser-amplifier system is used. The OPO generates signal pulses tunable over
a spectral range from 780 to 940 nm and idler pulses tunable from 1630 to 1190 nm. More than 250 mW are generated in the signal
beam and more than 300 mW in the idler beam. Without dispersion compensation chirped signal pulses with a pulse duration between
100 and 250 fs are measured. Using this system for coherent anti-Stokes Raman scattering spectroscopy, vibrational resonances
between 1110 and 6760 cm−1 can be excited. Due to the chirped pulses, a spectral resolution of 100 cm−1 is achieved, which is 2.5 times higher compared to an excitation with time-bandwidth limited pulses. 相似文献