title: Analysis of Lanthanide-Radical Magnetic Interactions in Ce(III) 2,2'-Bipyridyl Complexes.
abstract: A series of lanthanide complexes bearing organic radical ligands, [Ln(CpR)2(bipy·-)] [Ln = La, CpR= Cptt(1); Ln = Ce, CpR= Cptt(2); Ln = Ce, CpR= Cp″ (3); Ln = Ce, CpR= Cp‴ (4)] [Cptt= {C5H3tBu2-1,3}-; Cp″ = {C5H3(SiMe3)2-1,3}-; Cp‴ = {C5H2(SiMe3)3-1,2,4}-; bipy = 2,2'-bipyridyl], were prepared by reduction of [Ln(CpR)2(μ-I)]2or [Ce(Cp‴)2(I) (THF)] with KC8in the presence of bipy (THF = tetrahydrofuran). Complexes 1-4 were thoroughly characterized by structural, spectroscopic, and computational methods, together with magnetism and cyclic voltammetry, to define an unambiguous Ln(III)/bipy·-radical formulation. These complexes can act as selective reducing agents; for example, the reaction of 3 with benzophenone gives [{Ce(Cp")2(bipy)}2{κ2-O,O'-OPhC(C6H5)CPh2O}] (7), a rare example of a "head-to-tail" coupling product. We estimate the intramolecular exchange coupling for 2-4 using multiconfigurational and spin Hamiltonian methods and find that the commonly used Lines-type isotropic exchange is not appropriate, even for single 4f e-/organic radical pairs.
authors.affiliation: School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Ortu
authors.affiliation: School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Matthew
authors.initials: M
authors.lastname: Burton
authors.affiliation: School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Fowler
authors.affiliation: School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Alasdair
authors.initials: A
authors.lastname: Formanuik
authors.affiliation: School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Marie-Emmanuelle
authors.initials: ME
authors.lastname: Boulon
authors.affiliation: School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Nicholas F
authors.initials: NF
authors.lastname: Chilton
authors.affiliation: School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, U.K.
authors.forename: David P
authors.identifier: http://orcid.org/0000-0003-1575-7754
authors.initials: DP
authors.lastname: Mills