Synthesis and characterization of 3-thiophene carboxamides containing a pyridine ring: structure, electrochemistry, and complexation

A series of new thiophene amides containing a pyridine ring has been synthesized and characterized. Single crystal X-ray structures have been determined for four of the new substances which show two distinct patterns of hydrogen-bonding. The crystal structure of the copper (II) complex of one of the ligands shows that the bonding is O,N in a square planar geometry with perchlorate ions in the axial positions. The new compounds do not undergo electropolymerization due to primary oxidation of the amide function but tuning of the amide group by introduction of an electron-withdrawing group on the pyridine ring allows electropolymerization to occur.