Calixarene Dimers as Host Molecules for Biologically Important Di- and Oligophosphates

Conformational Mobility Study in Mono Quinone Derivative of Calix[4]arene by Low Temperature NMR Spectroscopy

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Calix[4]monoquinone (3) has been synthesized by oxidation of rigid cone conformation of tripropoxy calix[4]arene (2), and conformational characteristics of this molecule have been studied by means of dynamic nuclear magnetic resonance (DNMR) and HH- correlated nuclear magnetic resonance spectroscopy (HH-COSY NMR). On the basis of the data that have been obtained, free Gibbs energy of activation (ΔG#) for quinone ring interconversion process of 3 was determined 12.3±0.05 Kcal/mol by coalescence approximation method.

Moulding calixarenes for biomacromolecule targeting

After their successful use as a preorganized platform for the preparation of receptors for metal ions and small neutral molecules over the last 15 years, calixarenes are enjoying a renaissance of popularity as scaffolds for ligands that are able to efficiently and selectively target macromolecules such as proteins/enzymes, nucleic acids and lipids. This feature article summarizes the peculiar factors characterizing the calixarene structure and properties, as well as outlines the main rules that can be used to turn such macrocycles into efficient and successful ligands for these classes of biomacromolecules. Factors that affect the multivalent properties of calixarenes, such as the size, conformation and stereochemical presentation of binding groups or their amphiphilicity and hybrid character, are described in detail with the use of a few selected examples from the literature. Perspectives and applications of these ligands in bionanotechnology and nanomedicine, such as protein sensing and inhibition, gene-delivery, targeted drug-delivery and cell imaging, are also discussed.