title: Steric control of lanthanide hydration state: fast water exchange at gadolinium in a mono-amide 'DOTA' complex.
abstract: Detailed analyses of the solution structure and exchange dynamics of two sets of homologous mono-amide triacetate lanthanide complexes (Ln = Eu, Gd) of cyclen have been undertaken. The complex [LnL1], bearing an N-linked CH2CH2NHCO-pyridyl moiety, forms mono-aqua (q = 1) species in solution and the Gd complex undergoes rapid water exchange (k(ex)= 11 x 10(7) s(-1), 298 K) as a result of the steric destabilisation of the Ln-water binding interaction. The homologous complex with a C-3 spacing chain, [LnL2], forms a q = 0 species.
authors.affiliation: Department of Chemistry, University of Durham, South Road, Durham, DH1 3LE, UK.
authors.forename: Aileen
authors.initials: A
authors.lastname: Congreve
authors.forename: David
authors.initials: D
authors.lastname: Parker
authors.forename: Eliana
authors.initials: E
authors.lastname: Gianolio
authors.forename: Mauro
authors.initials: M
authors.lastname: Botta