182305-75-5Relevant academic research and scientific papers
New upper rim pyridine-bridged calix[4]arenes: Synthesis and complexation properties toward neutral molecules and ammonium ions in organic media
Arduini, Arturo,McGregor, William M.,Pochini, Andrea,Secchi, Andrea,Ugozzoli, Franco,Ungaro, Rocco
, p. 6881 - 6887 (2007/10/03)
A new series of calix[4]arenes, diametrically bridged at the upper rim with pyridino systems, has been synthesized. The shape, rigidity, and chemical structure of the bridge influence the host-guest complexation properties of these systems in solution toward several neutral molecules having acidic C-H bonds. Additionally, selective complexation of methylammonium tosylate in comparison with other ammonium salts has been observed and the strength of this complexation enhanced by electron-donor ability of the p-substituent on the pyridine moiety of the calixarene host. X-ray crystal structures of endo complexes of host 5 with malononitrile and nitromethane have been resolved, verifying specific C-H bonding with the hard oxygen and nitrogen atoms of the bridge and the soft aromatic ring of the calixarene.
