title: Self-assembled tetragonal prismatic molecular cage highly selective for anionic π guests.
abstract: The metal-directed supramolecular synthetic approach has paved the way for the development of functional nanosized molecules. In this work, we report the preparation of the new nanocapsule 3·(CF(3)SO(3))(8) with a A(4 B(2) tetragonal prismatic geometry, where A corresponds to the dipalladium hexaazamacrocyclic complex Pd-1, and B corresponds to the tetraanionic form of palladium 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (2). The large void space of the inner cavity and the supramolecular affinity for guest molecules towards porphyrin-based hosts converts this nanoscale molecular 3D structure into a good candidate for host-guest chemistry. The interaction between this nanocage and different guest molecules has been studied by means of NMR, UV/Vis, ESI-MS, and DOSY experiments, from which highly selective molecular recognition has been found for anionic, planar-shaped π guests with association constants (K(a)) higher than 10(9) M(-1) , in front of non-interacting aromatic neutral or cationic substrates. DFT theoretical calculations provided insights to further understand this strong interaction. Nanocage 3·(CF(3)SO(3))(8) can not only strongly host one single molecule of M(dithiolene)(2) complexes (M=Au, Pt, Pd, and Ni), but also can finely tune their optical and redox properties. The very simple synthesis of both the supramolecular cage and the building blocks represents a step forward for the development of polyfunctional supramolecular nanovessels, which offer multiple applications as sensors or nanoreactors.
authors.affiliation: QBIS Group, Departament de Química, Institut de Química Computacional I Catàlisis (IQCC), Universitat de Girona, Campus Montilivi, E17071 Girona, Catalonia, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: García-Simón
authors.forename: Marc
authors.initials: M
authors.lastname: Garcia-Borràs
authors.forename: Laura
authors.initials: L
authors.lastname: Gómez
authors.forename: Isaac
authors.initials: I
authors.lastname: Garcia-Bosch
authors.forename: Sílvia
authors.initials: S
authors.lastname: Osuna
authors.forename: Marcel
authors.initials: M
authors.lastname: Swart
authors.forename: Josep M
authors.initials: JM
authors.lastname: Luis
authors.forename: Concepció
authors.initials: C
authors.lastname: Rovira
authors.forename: Manuel
authors.initials: M
authors.lastname: Almeida
authors.forename: Inhar
authors.initials: I
authors.lastname: Imaz
authors.forename: Daniel
authors.initials: D
authors.lastname: Maspoch
authors.forename: Miquel
authors.initials: M
authors.lastname: Costas
authors.forename: Xavi
authors.initials: X
authors.lastname: Ribas