324 Boron Calix[3]Arenes and Hemicarcerands: Design, Synthesis and Evaluation as Molecular Receptors

Thursday, November 5, 2009: 3:00 PM
Rio Grande (Camino Real Hotel)
Victor Barba , Centro de Investigaciones Químicas, Universidad autonoma del Estado de Morelos, Cuernavaca, Mexico
As a result of their good inclusion properties, calix-like compounds have become common hosts for a large variety of guest molecules.  Calixarenes are important receptor molecules and the replacement of the carbon bridge with other heteroatoms has been carried out to study effects such as conformation and complexation of guest molecules. We have development the synthesis of boron macrocyclic receptors using a one-pot strategy. The structure of these hosts is related to calixarenes and hemicarcerands, wherein the carbon bridges between the aromatic rings have been replaced by coordinative N-B bonds. The behavior of these boron-calixarenes towards the inclusion of small organic molecules has been analyzed by UV spectroscopy, 1H NMR and X-ray diffraction analysis.  Interesting features for these macrocycles include: (i) a calix-shaped with hydrophobic cavity, (ii) good solubility in organic solvents, (iii) enclosure of small guest molecules, (iv) presence of two sites for the simultaneous inclusion of two or more guest molecules and (v) presence of reaction sites in the molecule which can be substituted by other functional groups. These new class of calixarene analogues using boron-nitrogen coordinative bonds represents an important way for the construction of molecular containers.
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