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 theN-Methylaminocarbonyl Linker

A series of cone 5,17-bis( N -arylaminocarbonyl)calix[4]arenes were synthesized 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]arenes were studied in solution by NMR spectroscopy and in the solid state by X-ray structural resolution. The use of the N -methylaminocarbonyl linker between the calix[4]arene and the aromatic substituent was found to have a dominant 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 design of molecular receptors.