10.1002/anie.200703971
The study investigates the host–guest chemistry of a new class of hydrogen-bonding receptors based on 2,6-bis(2-anilinoethynyl)pyridine sulfonamide derivatives. These receptors form 2+2 dimers with water, halides, or both, depending on the protonation state of the receptor. The neutral receptors form dimers with water molecules, while the protonated receptors form dimers with halides such as chloride and bromide. The study shows that water and halide anions can serve the same structural role in these self-assembled systems. The researchers used techniques such as 1H NMR spectroscopy, UV/Vis spectroscopy, and single crystal X-ray diffraction to characterize the dimerization behavior and binding properties of these receptors. The findings suggest that these receptors could be used as sensors for the selective recognition of guest molecules.
10.1515/HC.2007.13.2-3.113
The study investigates the reactions of 4-(4-methylbenzoyl)-5-(4-methylphenyl)-2,3-furandione (1) with various semi-/thiosemi-carbazones (2a-h). These reactions result in the formation of l-methylenaminopyrimidine-2-one and -thione derivatives (3a-h) through the loss of carbon dioxide and water, with yields ranging from 43% to 59%. The newly synthesized compounds were characterized using elemental analyses, IR, 'H and 13C NMR spectral data. The study also explores the hydrolysis of specific compounds, 5-(4-methylbenzoyl)-1-(methyl-4-methylphenylmethylenamino)-4-(4-methylphenyl)-1//-pyrimidine-2-one (3c) and 5-(4-methylbenzoyl)-4-(4-methylphenyl)-1-(phenylmethylenamino)-1//-pyrimidine-2-thione (3h), leading to the formation of 1-amino-5-(4-methylbenzoyl)-4-(4-methylphenyl)-1//-pyrimidine-2-one (4) and 1-amino-5-(4-methylbenzoyl)-4-(4-methylphenyl)-1//-pyrimidine-2-thione (5). The aim of the study is to contribute to the understanding of this class of heterocyclic compounds, which have significant biological and medical interest due to their potential applications in treating various diseases.
10.1021/ja200941a
The study investigates the reversible formation of linear main-chain supramolecular polymers using a small ditopic monomer 1 that features two orthogonal binding interactions: metal-ligand binding and ion pair formation. The monomer 1 consists of a terpyridine ligand attached to a self-complementary guanidiniocarbonyl pyrrole carboxylate zwitterion. The terpyridine ligand forms a 1:2 metal complex with Fe(II) ions, while the zwitterion dimerizes through ion pairs. These interactions drive the self-assembly of monomer 1 into linear supramolecular polymers in polar solvents like DMSO and water. The polymerization can be reversibly controlled by adding or removing metal ions (using a competing ligand like HEEDTA) or by adjusting the pH to protonate or deprotonate the zwitterion. The study employs various techniques, including UV/vis spectroscopy, viscosity measurements, TEM, cryo-TEM, DLS, and SANS, to demonstrate the formation of linear polymers that further aggregate into larger globular structures. The findings highlight the potential of this system for developing stimuli-responsive materials.
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