Synthesis and structural properties of 5,17-bis(N-methyl-N-arylaminocarbonyl)calix[4]arenes. Directing the substituents toward the cavity by use of the cis-generating property of the N-methylaminocarbonyl linker

A series of cone 5,17-bis(N-arylaminocarbonyl)calix[4]arenes were synthesiz ed and N-methylated using an easy and high-yielding methylation procedure. The structures of the cone 5,17-bis(N-methyl-N-arylaminocarbonyl)calix[4]ar ene were studied in solution by NMR spectroscopy and in the solid state by X-ray structural resolution. The use of the N-methylaminocarbonyl linker be tween the calix[4]arene and the aromatic substituent was found to have a do minant influence on the molecular structure, forcing the substituent toward the cavity of the calix[4]arene regardless of the size of the substituent. The linker may be a very useful structure generator when considering the d esign of molecular receptors.