title: When self-assembly fails: stepwise metal-directed synthesis of [2]catenanes.
abstract: On the attempted synthesis of a series of homo- and heterotrimetallic [2]catenanes by the self-assembly of a 2-(pyridin-4-ylmethyl)-2,7-diazapyrenium ligand, (ethylenediamine)palladium(II) or platinum(II) nitrate, and a dioxoaryl bis(N-monoalkyl-4,4'-bipyridinium) salt as building blocks, both the one-pot direct self-assembly of the components and the so called "magic ring" approach fail to produce the expected trinuclear [2]catenanes under thermodynamically driven conditions. However, one of the target supramolecules is obtained by following a stepwise protocol, consisting of the threading of a dinuclear Pt(II) metallacycle and the dioxoaryl bis(N-monoalkyl-4,4'-bipyridinium) axle, followed by kinetically controlled Pt(II) -directed cyclization of the corresponding pseudorotaxane.
authors.affiliation: Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Universidade da Coruña, Facultad de Ciencias, Rúa da Fraga 10, 15071A Coruña (Spain).
authors.forename: Eva M
authors.initials: EM
authors.lastname: López-Vidal
authors.forename: Marcos D
authors.initials: MD
authors.lastname: García
authors.forename: Carlos
authors.initials: C
authors.lastname: Peinador
authors.forename: José M
authors.initials: JM
authors.lastname: Quintela
mesh_terms: D043863:Catenanes / Q000737:chemistry*; D003500:Cyclization; D015394:Molecular Structure
chemical_list: D043863:Catenanes
keywords: catenanes; molecular recognition; platinum; self-assembly; supramolecular chemistry