Hydrogen-Bonding and Pi-Stacking Induced Self-Assembly of Picolinic Acid-Substituted Phthalocyanine Derivatives
We present here a new family of picolinic acid-terminated Pcs (1-3, Figure 1) which are able to self-aggregate in different solvents giving rise to the formation of columnar H-aggregates as a result of a combination of π-π supramolecular interactions between the Pc macrocycles and hydrogen bonding interactions between the terminal picolinic acid moieties. Remarkably, the assembly/disassembly of these supramolecular systems can be reversible controlled by the addition of acids or bases to the Pc solutions. In Pc 3, chiral alkoxy units have been introduced at the Pc peripheral positions with the aim of influencing the stacking of the H-aggregates towards the formation of single-handed columnar structures.
1. Special issue on “Supramolecular approaches to organic electronics and nanotechnology”. Adv. Mater. 2006, 18, 1227-1329.
2. Special issue on “Supramolecular chemistry and self-assembly”. Science 2002, 295, 2395-2421.
3. G. de la Torre, C.G. Claessens, T. Torres Chem. Commun. 2007, 2000-2015.
4. G. Bottari, G. de la Torre, D. M. Guldi, T. Torres Chem. Rev. 2010, 110, 6768-6816.
5. G. Bottari, J. A. Suanzes, O. Trukhina, T. Torres J. Phys. Chem. Lett. 2011, 2, 905-913.