During a synthesis of the well-known and useful building block 6-hexa-O-tert-butyldimethylsilyl α-cyclodextrin (2) by silylation of α-cyclodextrin (1) we isolated as a byproduct the oversilylated 2,6-hepta-O-tert-butyldimethylsilyl α-cyclodextrin (3) where one 2-OH group has also been silylated. This unsymmetrical new compound has a remarkable H NMR spectrum in CDCl where all 11 alcohol groups are visible. We have analyzed the spectrum of 3 using 1D and 2D 800 MHz NMR and are able to assign all the 11 alcohol protons.
View Article and Find Full Text PDFIsopropyl 1-thio-β-D-galactopyranoside (IPTG, 1) is used widely as an inducer of protein expression in and 1-β-D-galactopyranosyl-2-methylpropane (2), a -glycoside analogue of 1, has also been identified as an inducer. Here, synthesis and study of mimetics of 1 and 2, 1-β-D-galactopyranosyl-2-methylpropan-1-ols and two cyclic acetals derivatives, that constrain the presentation of the iPr group in various geometries is described. Conformational analysis of -glycosides in protic solvent is performed using (i) Desmond metadynamics simulations (OPLS4) and (ii) use of values obtained by H-NMR spectroscopy.
View Article and Find Full Text PDFWhile being some of the oldest supramolecular hosts, cyclodextrins remain very popular as molecular binders in materials, devices, artificial enzymes and more. The popularity is undoubtedly connected to the ready availability, carbohydrate biomass origin, biodegradability and water solubility of the cyclodextrins. Many of these applications require synthetic modification of the cyclodextrin - at the simplest the attachment of a linker - but also often attachment of several functional groups, lids, bridges .
View Article and Find Full Text PDFMethane is one of the most potent greenhouse gases; developing technology for its abatement is essential for combating climate change. Copper zeolites can activate methane at low temperatures and pressures, demonstrating promise for this technology. However, a barrier to industrial implementation is the inability to recycle the Cu(II) active site.
View Article and Find Full Text PDFThis review highlights UV-vis-NIR range absorption spectroscopy in catalysis. A variety of experimental techniques identifying reaction mechanisms, kinetics, and structural properties are discussed. Stopped flow techniques, use of laser pulses, and use of experimental perturbations are demonstrated for studies of enzymatic, homogeneous, heterogeneous, and photocatalysis.
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