No abstract

A M2L2 rectangular-shaped metallacycle, obtained by metal-directed self-assembly of a 2-(pyridin-4-ylmethyl)-2,7-diazapyrenium salt and [(en)Pd(NO3)2 (en=ethylenediamine), has been investigated as a molecular receptor for a wide range of aromatic substrates in water. Complexation and catenation of the receptor with selected mono- and polycyclic aromatic substrates produced 1:1 inclusion complexes and [2]catenanes in a highly efficient fashion, as determined by NMR and UV/Vis spectroscopic techniques, as well as single-crystal X-ray crystallography. Furthermore, the thermodynamic and kinetic features of the complexation processes have been analyzed for selected model guests.

We present here the design and synthesis of a series of multicomponent supramolecular architectures, structures formed by the Pd /Pt -directed integrative social self-sorting in aqueous media of pairs of complementary N-monoalkyl-4,4'-bipyridinium/2,7-diazapyrenium-based ligands. Out of the different potential outcomes of the processes, we have found out how the designed systems selectively enhance the production of pseudo[1]rotaxanes, hermaphroditic host-guest aggregates that maximize the strength of the occurring π-π, C-H⋅⋅⋅π, and hydrophobic interactions, as well as the number of those interactions per receptor. It is also demonstrated how both integrative social and narcissistic Pd -directed self-sorting can occur orthogonally and concomitantly for this type of ditopic ligands.

We present herein the efficient palladium(II)-directed self-assembly in water of a series of nine new diversely functionalized metallacycles, owning hydroxy/alkoxycarbonyl/azidoalkyl exo pendant groups attached to ditopic N-monoalkyl/aryl-4,4'-bipyridinium/2,7-diazapyrenium ligands. The highly convergent and versatile synthetic route for the ligands uses the Zincke reaction between (dinitrophenyl)bipyridinium/diazapyrenium salts and racemic amines as the key step. The stereochemical outcome of the self-assembly of the Pd2L2 species is discussed on the basis of density functional theory quantum-chemical calculations.