18-crown-6
18-crown-6 - Related Videos
02:36
Crown Ethers
0 Views •
2023
Crown ethers are cyclic polyethers that contain multiple oxygen atoms, usually arranged in a regular pattern. The first crown ether was synthesized by Charles Pederson while working at DuPont in 1967. For this work, Pedersen was co-awarded the 1987 Nobel Prize in Chemistry. Crown ethers are named using the formula x-crown-y, where x is the total number of atoms in the ring and y is the number of ether oxygen atoms. The term 'crown' refers to the crown-like shape that these ether molecules take.
![Microwave-assisted One-pot Synthesis of <em>N</em>-succinimidyl-4-[<sup>18</sup>F]fluorobenzoate ([<sup>18</sup>F]SFB)](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F2755.jpg%3Fv%3D2026-09-01%252004%253A39%253A14&w=750&q=75)
08:33
Microwave-assisted One-pot Synthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB)
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Cited by 15 •
2011
A facile, one-pot synthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB) was developed based on a non-aqueous, three-step radiochemical process. Using microwave heating, the entire procedure can be completed in less than 30 min, or 60 min with further purification by preparative HPLC. The decay-corrected radiochemical yields (RCYs) were 35-5% (n > 30).
10:50
Assessment of Immunologically Relevant Dynamic Tertiary Structural Features of the HIV-1 V3 Loop Crown R2 Sequence by ab initio Folding
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Cited by 10 •
2010
The crown region of different V3 loop sequences of the surface envelope glycoprotein (gp120) of HIV-1 can be structurally characterized in many cases by in silico folding of positions 10 to 22 of the loop using a state-of-the-art ab initio folding algorithm. Here we demonstrate the folding and evaluation of this region of the V3 loop from the R2 strain of HIV-1, a uniquely neutralization sensitive strain with puzzling functional properties.
09:27
Wind Tunnel Experiments to Study Chaparral Crown Fires
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Cited by 7 •
2017
This protocol describes wind tunnel experiments designed to study the transition of a fire from the ground to the canopy of chaparral shrubs.
09:43
Protease- and Acid-catalyzed Labeling Workflows Employing 18O-enriched Water
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Cited by 2 •
2013
Stable isotope labeling workflows employing 18O-enriched water (LeO-workflows) are versatile tools for quantitative and qualitative proteomics studies. In protease-assisted (PALeO) workflows, 18O-atoms are introduced by proteolytic cleavage and carboxyl oxygen exchange reactions mediated by proteases. In the acid-catalyzed (ALeO) workflow, 18O-atoms are introduced by carboxyl oxygen exchange at low pH.
FAQs
The six oxygen atoms create a coordinated donor environment inside the ring. Their lone pairs point toward the cavity, allowing interaction with a positively charged metal ion. Because the cavity particularly favors potassium, binding behavior reflects geometric fit as well as charge attraction. This selectivity underlies host–guest recognition in solution.
The oxygen atoms are chemically important because their lone pairs provide the donor sites that coordinate positively charged metal ions. Their arrangement around the ring allows a cation to interact with several oxygen atoms within the host rather than at only one point. This coordination helps explain why ring geometry and cavity dimensions influence recognition and selectivity.
Selective cation binding gives 18-crown-6 a controllable host–guest interaction rather than a purely nonspecific association. In supramolecular chemistry, that distinction supports the design of molecular assemblies whose interactions can be regulated through cation recognition. The molecule therefore serves both as a binding host and as a component for studying how recognition directs larger chemical structures.
In cation separation, the key strategy is to exploit differences in how metal ions fit and coordinate within the crown ether cavity. The particular preference for potassium provides a chemically meaningful basis for distinguishing cations. This application translates molecular-scale recognition into a separation function, allowing 18-crown-6 to serve as a selective host rather than only as a reaction additive.
Analytical chemistry and complex formation studies use 18-crown-6 to examine which cations associate with the host and how that association reflects selective recognition. Such work can focus on the formation of host–cation complexes, while analytical applications use differences in binding behavior. These studies connect observed chemical behavior with the underlying supramolecular interaction.
18-Crown-6 can increase the solubility and reactivity of inorganic salts in organic solvents by coordinating their metal cations. That change helps ionic reagents participate more effectively in an organic-solvent environment. The same cation-binding behavior explains its use as a phase-transfer catalyst, linking molecular recognition with reaction-enabling solvent compatibility.