title: Linear polynuclear helicates as a link between discrete supramolecular complexes and programmed infinite polymetallic chains.
abstract: The contribution of the solvation energies to the assembly of polynuclear helicates reduces the free energy of intermetallic repulsion, DeltaE(MM), in condensed phase to such an extent that stable D(3)-symmetrical tetranuclear lanthanide-containing triple-stranded helicates [Ln(4)(L4)(3)](12+) are quantitatively produced at millimolar concentrations, despite the twelve positive charge borne by these complexes. A detailed modelling of the formation constants using statistical factors, adapted to self-assembly processes involving intra- and intermolecular connections, provides a set of five microscopic parameters, which can be successfully used for rationalizing the stepwise generation of linear bi-, tri- and tetranuclear analogues. Photophysical studies of [Eu(4)(L4)(3)](12+) confirm the existence of two different binding sites producing differentiated metal-centred emission at low temperature, which transforms into single site luminescence at room temperature because of intramolecular energy funelling processes.
authors.affiliation: Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, 1211 Geneva 4, Switzerland.
authors.forename: Natalia
authors.initials: N
authors.lastname: Dalla-Favera
authors.forename: Josef
authors.initials: J
authors.lastname: Hamacek
authors.forename: Michal
authors.initials: M
authors.lastname: Borkovec
authors.forename: Damien
authors.initials: D
authors.lastname: Jeannerat
authors.forename: Frédéric
authors.initials: F
authors.lastname: Gumy
authors.forename: Jean-Claude G
authors.initials: JC
authors.lastname: Bünzli
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Ercolani
authors.forename: Claude
authors.initials: C
authors.lastname: Piguet