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Lu X Fanfair DD Johnston KP Korgel BA 《Journal of the American Chemical Society》2005,127(45):15718-15719
High yields of crystalline Ge nanowires were synthesized for the first time in a conventional solvent of trioctylphosphine by disproportionating GeI2 in the presence of Bi nanoparticle growth seeds at 350 degrees C and atmospheric pressure. 相似文献
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Heitsch AT Fanfair DD Tuan HY Korgel BA 《Journal of the American Chemical Society》2008,130(16):5436-5437
Here we report the solution-liquid-solid (SLS) synthesis of silicon (Si) nanowires. Nanowires are grown by trisilane (Si3H8) decomposition in a high boiling solvent, octacosane (C28H58) or squalane (C30H62), in the presence of either Au or Bi nanocrystals. To our knowledge, this is the first report of a colloidal synthetic route carried out in a solvent at atmospheric pressure that provides crystalline Si nanowires in large quantities. 相似文献
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Lopa V. Desai Michael B. Hay David K. Leahy Carolyn Wei Dayne Fanfair Thorsten Rosner Yi Hsiao 《Tetrahedron》2013,69(27-28):5677-5684
The Pd-catalyzed α-arylation of cycloheptapyridyl ketone is a key complexity-building step in the synthesis of BMS-846372, a CGRP antagonist. A first-generation process utilized Pd(OAc)2/PtBu3·HBF4 catalyst system with a strong base NaOtBu. Although this process was demonstrated on multi-kilo scale, the harsh conditions led to non-selective metal catalyzed processes, which generated several operational, quality, and throughput issues. By acquiring detailed knowledge around several important process parameters, we were able to design an efficient and scalable second-generation α-arylation process using a Pd(OAc)2/RuPhos catalyst system with the weaker base, K3PO4 in tert-amyl alcohol. This new weak base process was high yielding, efficient, and superior in several respects compared to the strong base process. The strategy behind the reaction and isolation development and the process considerations important to scaling a catalytic reaction from laboratory to manufacturing scale will be discussed. 相似文献
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Dr. Stefan Fischer Chris Siefe Dr. Dayne F. Swearer Dr. Claire A. McLellan Prof. A. Paul Alivisatos Prof. Jennifer A. Dionne 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(48):21787-21796
Upconverting nanoparticles (UCNPs) are promising candidates for photon-driven reactions, including light-triggered drug delivery, photodynamic therapy, and photocatalysis. Herein, we investigate the NIR-to-UV/visible emission of sub-15 nm alkaline-earth rare-earth fluoride UCNPs (M1−xLnxF2+x, MLnF) with a CaF2 shell. We synthesize 8 alkaline-earth host materials doped with Yb3+ and Tm3+, with alkaline-earth (M) spanning Ca, Sr, and Ba, MgSr, CaSr, CaBa, SrBa, and CaSrBa. We explore UCNP composition, size, and lanthanide doping-dependent emission, focusing on upconversion quantum yield (UCQY) and UV emission. UCQY values of 2.46 % at 250 W cm−2 are achieved with 14.5 nm SrLuF@CaF2 particles, with 7.3 % of total emission in the UV. In 10.9 nm SrYbF:1 %Tm3+@CaF2 particles, UV emission increased to 9.9 % with UCQY at 1.14 %. We demonstrate dye degradation under NIR illumination using SrYbF:1 %Tm3+@CaF2, highlighting the efficiency of these UCNPs and their ability to trigger photoprocesses. 相似文献
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Dayne C. Georgiou Bradley D. Stringer Dr. Conor F. Hogan Dr. Peter J. Barnard Dr. David J. D. Wilson Dr. Nicole Holzmann Prof. Dr. Gernot Frenking Dr. Jason L. Dutton 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3377-3386
The attempted synthesis of NHC‐stabilized dicarbon (NHC?C?C?NHC) through deprotonation of a doubly protonated precursor ([NHC?CH?CH?NHC]2+) is reported. Rather than deprotonation, a clean reduction to NHC?CH?CH?NHC is observed with a variety of bases. The apparent resistance towards deprotonation to the target compound led to a reinvestigation of the electronic structure of NHC→C?C←NHC, which showed that the highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) gap is likely too small to allow for isolation of this species. This is in contrast to the recent isolation of the cyclic alkylaminocarbene analogue (cAAC?C?C?cAAC), which has a large HOMO–LUMO gap. A detailed theoretical study illuminates the differences in electronic structures between these molecules, highlighting another case of the potential advantages of using cAAC rather than NHC as a ligand. The bonding analysis suggests that the dicarbon compounds are well represented in terms of donor–acceptor interactions L→C2←L (L=NHC, cAAC). 相似文献
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