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Synthesis of Structurally Varied 1,3‐Disiloxanediols and Their Activity as Anion‐Binding Catalysts 下载免费PDF全文
Kayla M. Diemoz Sean O. Wilson Prof. Dr. Annaliese K. Franz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18349-18353
A series of new 1,3‐disiloxanediols has been synthesized, including naphthyl‐substituted and unsymmetrical siloxanes, and demonstrated as a new class of anion‐binding catalysts. In the absence of anions, diffusion‐ordered spectroscopy (DOSY) displays self‐association of 1,3‐disiloxanediols through hydrogen‐bonding interactions. Binding constants determined for 1,3‐disiloxanediol catalysts indicate strong hydrogen‐bonding and anion‐binding abilities with unsymmetrical siloxanes displaying different hydrogen‐bonding abilities for each silanol group. 相似文献
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Dr. Dariusz G. Piekarski Pascal Steinforth Dr. Melania Gómez-Martínez Dr. Julia Bamberger Florian Ostler Prof. Dr. Monika Schönhoff Prof. Dr. Olga García Mancheño 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(72):17598-17603
H-bond donor catalysts able to modulate the reactivity of ionic substrates for asymmetric reactions have gained great attention in the past years, leading to the development of cooperative multidentate H-bonding supramolecular structures. However, there is still a lack of understanding of the forces driving the ion recognition and catalytic performance of these systems. Herein, insight into the cooperativity nature, anion binding strength, and folding mechanism of a model chiral triazole catalyst is presented. Our combined experimental and computational study revealed that multi-interaction catalysts exhibiting weak binding energies (≈3–4 kcal mol−1) can effectively recognize ionic substrates and induce chirality, while strong dependencies on the temperature and solvent were quantified. These results are key for the future design of catalysts with optimal anion binding strength and catalytic activity in target reactions. 相似文献
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Dr. Ewa Pacholska-Dudziak Dr. Sandra Hojniak-Thyssen Prof. Dr. Lechosław Latos-Grażyński 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(51):11859-11863
An expanded triphyrin containing a bipyrrole moiety and annulene links, namely tetraphenyl-[22]triphyrin(6.5.0), 2 , has been synthesized. The synthesis proceeded by a postsynthetic transformation of tetraphenyl-[22]triphyrin(6.6.0), 1 , in a metal-free unexpected and unprecedented ring contraction during column chromatography on alumina. The observed transformation, located at the hydrocarbon chain linking the pyrrole units, formally corresponds to a subtraction of one carbon atom from an annulene circuit. In contrast to the flexible substrate 1 , the product 2 is conformationally rigid, and capable of chloride anion binding in its protonated form. 相似文献
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Abstract A bromine-81 NMR study was conducted to characterize the Cl?-binding site of porcine pancreatic α-amylase. Only a single signal was observed in the spectrum in the presence of an equimolar concentration of the enzyme and NaBr. the signal was assigned to free Br ions, which are in very slow exchange with the protein-bound Br on an NMR time scale. the presence of a common anion-binding site was demonstrated from the competition of Br with F?, Cl?, NO? 3, and ClO? 4 for the site. 相似文献
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