2,2':4,4'':4',4'''-Quaterpyridyl: A Building Block for the Preparation of Novel Redox Reagents. 1. Preparation and Quaternization

Article abstract of DOI:10.1021/jo00294a007

An efficient preparation of 2,2':4,4'':4',4'''-quaterpyridyl (qpy) from 4,4'-bipyridine is described, using palladium on charcoal.Conditions are described for the selective methylation of the nitrogen atoms present.This has allowed the preparation of mono- and dimethylquaternary salts that retain an α-diimine site for complexation to a metal.These quarternary salts can be used to prepare complexes in which metal ions are coordinated to viologen-type ligands.Electrochemical and spectroscopic measurements of the diquarternary salt derived from qpy suggest that it behaves as two separate or weakly interacting monoquat moieties.