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排序方式: 共有285条查询结果,搜索用时 46 毫秒
1.
Dr. Dhanaji V. Jawale Dr. Edmond Gravel Dr. Nimesh Shah Dr. Vincent Dauvois Prof. Dr. Haiyan Li Prof. Dr. Irishi N. N. Namboothiri Dr. Eric Doris 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7039-7042
Rhodium nanoparticles were anchored on carbon nanotubes and the resulting nanohybrid was studied as co‐catalyst, along with tert‐butylcatechol, for the dehydrogenation of various N‐heterocycles. The co‐catalytic system operates in high yields, under the mildest conditions reported so far, and can be applied to a wide variety of secondary amine‐containing scaffolds. 相似文献
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A number of reporter molecules of the structure R-(CH2)n-N+(CH3)2(CH2)mN+(CH3)3·2Br?, where R is a chromophore absorbing in the 300–500 mp region, have been synthesized. The effect of DNA and RNA on the absorption, induced circular dichroism, and proton magnetic resonance spectra is reported. A red shift and a hypochromic effect on the absorption spectra of the bound chromophore is observed. In all cases where R is an “unsymmetrical” 4-nitroaniline chromophore, it is found that DNA and RNA induce an opposite CD in the absorption band of the bound reporter molecules. These results together with PMR studies are interpreted in terms of the structure of the nucleic acid systems in solutions. 相似文献
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CpZrCl3·dme was treated with Na[El(OtBu)3], El = Ge, Sn, Pb, respectively. The addition of Na[Sn(OtBu)3] to CpZrCl3·dme caused rapid cyclopentadienide loss and the equally rapid appearance of CpSnCl, half of which crystallized as the trinuclear complex {[ZrCl(OtBu)3]2·CpSnCl}. Pristine CpSnCl reacted almost instantly with NaOtBu to give NaCp and Na[Sn(OtBu)3], which co-crystallized as a coordination polymer. Na[Ge(OtBu)3] also displaced Cp from zirconium, but with a different product distribution, giving Cp2Ge, fac-[Ge(μ-tBuO)3ZrCl(OtBu)2], and ZrCl(OtBu)3. By contrast, Na[Pb(OtBu)3] only exchanged its tert-butoxide groups with zirconium to furnish CpZr(OtBu)3 and PbCl2. The solid-state structures of {[ZrCl(OtBu)3]2·CpSnCl}, fac-[Ge(μ-tBuO)3ZrCl(OtBu)2], and {NaCp·Na[Sn(OtBu)3]}n were determined. 相似文献
6.
Ionizable Amphiphilic Dendrimer‐Based Nanomaterials with Alkyl‐Chain‐Substituted Amines for Tunable siRNA Delivery to the Liver Endothelium In Vivo 下载免费PDF全文
Dr. Omar F. Khan Edmond W. Zaia Dr. Hao Yin Dr. Roman L. Bogorad Dr. Jeisa M. Pelet Dr. Matthew J. Webber Iris Zhuang Dr. James E. Dahlman Prof. Robert Langer Prof. Daniel G. Anderson 《Angewandte Chemie (International ed. in English)》2014,53(52):14397-14401
A library of dendrimers was synthesized and optimized for targeted small interfering RNA (siRNA) delivery to different cell subpopulations within the liver. Using a combinatorial approach, a library of these nanoparticle‐forming materials was produced wherein the free amines on multigenerational poly(amido amine) and poly(propylenimine) dendrimers were substituted with alkyl chains of increasing length, and evaluated for their ability to deliver siRNA to liver cell subpopulations. Interestingly, two lead delivery materials could be formulated in a manner to alter their tissue tropism within the liver—with formulations from the same material capable of preferentially delivering siRNA to 1) endothelial cells, 2) endothelial cells and hepatocytes, or 3) endothelial cells, hepatocytes, and tumor cells in vivo. The ability to broaden or narrow the cellular destination of siRNA within the liver may provide a useful tool to address a range of liver diseases. 相似文献
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Edmond W. H. Lee 《Algebra Universalis》2009,61(1):31-58
It is shown that the monoid E
n
of extensive transformations of a chain of order n is hereditarily finitely based if and only if n ≤ 3. It follows that the submonoid OE
n
of order-preserving transformations in E
n
is also hereditarily finitely based if and only if n ≤ 3. 相似文献
8.
Shubhangi B. Umbarkar Trupti V. Kotbagi Ankush V. Biradar Renu Pasricha Jyoti Chanale Mohan K. Dongare Anne-Sophie Mamede Christine Lancelot Edmond Payen 《Journal of molecular catalysis. A, Chemical》2009,310(1-2):150-158
Acetalization of glycerol with various aldehydes has been carried out using mesoporous MoO3/SiO2 as a solid acid catalyst. A series of MoO3/SiO2 catalysts with varying MoO3 loadings (1–20 mol%) were prepared by sol–gel technique using ethyl silicate-40 and ammonium heptamolybdate as silica and molybdenum source respectively. The sol–gel derived samples were calcined at 500 °C and characterized using various physicochemical characterization techniques. The XRD of the calcined samples showed the formation of amorphous phase up to 10 mol% MoO3 loading and at higher loading of crystalline α-MoO3 on amorphous silica support. TEM analyses of the materials showed the uniform distribution of MoO3 nanoparticles on amorphous silica support. Raman spectroscopy showed the formation of silicomolybdic acid at low Mo loading and a mixture of α-MoO3 and polymolybdate species at high Mo loadings. Moreover the Raman spectra of intermediate loading samples also suggest the presence of β-MoO3. Acetalization of glycerol with benzaldehyde was carried out using series of MoO3/SiO2 catalysts with varying MoO3 loadings (1–20 mol%). Among the series, MoO3/SiO2 with 20 mol% MoO3 loadings was found to be the most active catalyst in acetalization under mild conditions. Maximum conversion of benzaldehyde (72%) was obtained in 8 h at 100 °C with 60% selectivity for the six-membered acetal using 20% MoO3/SiO2. Interestingly with substituted benzaldehydes under same reaction conditions the conversion of aldehydes decreased with increase in selectivity for six-membered acetals. These results indicate the potential of this catalyst for the acetalization of glycerol for an environmentally benign process. 相似文献
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