Linear polynuclear helicates as a link between discrete supramolecular complexes and programmed infinite polymetallic chains.
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.
Dalla-Favera
Natalia
N
Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, 1211 Geneva 4, Switzerland.
Hamacek
Josef
J
Borkovec
Michal
M
Jeannerat
Damien
D
Gumy
Frédéric
F
Bünzli
Jean-Claude G
JC
Ercolani
Gianfranco
G
Piguet
Claude
C