Self-assembly of tricuprous double helicates: Thermodynamics, kinetics, and mechanism

N. Fatin-Rouge , Sylvie Blanc (1) , A. Pfeil , A. Rigault , A.-M. Albrecht-Gary , J.-M. Lehn (2, 3)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
2 ISIS - Institut de Science et d'ingénierie supramoléculaires
3 Collège de France - Chaire Chimie des Interactions Moléculaires

We report in this paper the coordination and kinetic properties of two oligobipyridine strands, which contain three 2,2′-bipyridine subunits separated by oxydimethylene bridges, the 4,4′-bis(CONET2)-substituted L and the 4,4′-bis(CO2Et)-substituted L′. Spectrophotometric measurements allowed the characterization of thermodynamic complexes and kinetic intermediates* which are involved in the self-assembly process of L2Cu3 and L2Cu3 helicates. The reaction presents positive cooperativity for the binding of two 2,2′-bipyridine strands to the cuprous cations. While reactive kinetic intermediates* present distorted coordination geometries around Cu1, the final rearrangement of the tricuprous bistranded helicates allows more closely tetrahedral coordination of each cation and reduces the interactions. Differences in the bulkiness and electronic properties of the L and L′ substituents do not affect significantly the stability of the corresponding helicates, but greatly influence binding rates in the self-assembly process.

Keywords: Self assembly; Tricupurous double helicates; bipyridine; kinetics; spectrophotometry; thermodynamics

Domains: Chemical Sciences

N. Fatin-Rouge, Sylvie Blanc, A. Pfeil, A. Rigault, A.-M. Albrecht-Gary, et al.. Self-assembly of tricuprous double helicates: Thermodynamics, kinetics, and mechanism. Helvetica Chimica Acta, 2001, 84 (6), pp.1694-1711. ⟨10.1002/1522-2675(20010613)84:6<1694::AID-HLCA1694>3.0.CO;2-T⟩. ⟨hal-01458136⟩