title: Steric hindrance effects in the use of heterocyclic azodyestuffs as spectrophotometric reagents.
abstract: The heterocyclic azo dyestuffs 4-(n-methyl-2 -pyridylazo)-resorcinol (where n = 3', 4', 5', 6') have been prepared, and their possible use as spectrophotometric reagents investigated. The dyestuffs are shown to function analogously to the parent ligand 4-(2'-pyridylazo) resorcinol (PAR) in giving red complexes with the ions Co(2+), Ni(2+), Cu(2+), Zn(2+) and UO(2)(2+). Steric effects resulting from the position of the methyl group in the heterocyclic ring are shown to occur in relation both to the spectra of the dyestuffs themselves and to the sensitivity of their reactions with the metal ions.
authors.affiliation: Department of Chemistry and Metallurgy, Lanchester College of Technology, Coventry, England.
authors.forename: W J
authors.initials: WJ
authors.lastname: Geary
authors.forename: F
authors.initials: F
authors.lastname: Bottomley