[en] In this work, we have designed and synthesized five 4,4'-bipyridinium and 2,7-diazapyrenium- based ligands. Their self-assembly with square planar palladium (II) and platinum (II) complexes leads to square planar geometry metallacycles, both in aqueous and organic media. Due to its p-deficient character and the presence of a suitable size cavity, these metallacycles have proven to be receptors for aromatic substrates. In particular, polycyclic aromatic hydrocarbons (PAHs) such as anthracene, phenanthrene, pyrene and benzo[a]pyrene, which constitute an important group of environmental pollutants, interact with this type of metallacycles. We have studied the inclusion complexes with different metallacycles and PAHs in solid state and in solution. The obtained results indicate that the aromatic substrate is inserted into the metallacycle cavity and provides p interactions with bipyridinium or diazapirenium units. It also showed the importance of hydrophobic interactions in the formation of inclusion complexes. The ligand size determines metallacycle cavity dimensions and influences the selectivity of the host. We have studied the affinity of metallacycle 15 for different size and shape PAHs. The association constants of metallacycle 15 with PAHs in organic and aqueous media were measured. The potential of metallacycle 15 for the selective extraction of PAHs to the aqueous phase was explored by means of competitive extraction experiments. The obtained results showed a good correlation between the association constants in water for the inclusion complexes and the resulting percentages of PAHs extracted

[gl] Neste traballo deseñáronse e sintetizáronse cinco ligandos nitroxenados con unidades de tipo 4,4´-bipiridina e 2,7-diazapireno. Resumen A súa autoensamblaxe con complexos metálicos de paladio e platino de xeometría plano cadrada conduce, tanto en medio acuoso como orgánico, a metalociclos dinucleares de forma rectangular. Debido ó seu carácter p-deficiente e á presenza dunha cavidade do tamaño axeitado, estes metalociclos actúan como receptores de sustratos aromáticos. Concretamente, hidrocarburos policíclicos aromáticos (PAHs) como antraceno, pireno e benzo[a]pireno, que constitúen un importante grupo de contaminantes do medio ambiente, interaccionan con este tipo de metalociclos. Estudáronse os complexos de inclusión de diferentes metalociclos con PAHs tanto en disolución como en estado sólido. Os datos obtidos indican que o sustrato aromático se inserta na cavidade do receptor e establece interaccións p cás unidades de bipiridinio ou diazapirenio. Ademais, evidenciouse a importancia das interaccións hidrofóbicas na formación dos complexos de inclusión. O tamaño do ligando determina as dimensións da cavidade do metalociclo, que o mesmo tempo inflúe na selectividade do receptor fronte ó PAH. Estudouse a afinidade do metalociclo 15 por una serie de PAHs seleccionados polo seu diferente tamaño e forma, determinando as constantes de asociación con varios PAHs en distintos disolventes. Explorouse o potencial do metalociclo 15 na extracción selectiva de PAHs ó medio acuoso. Os resultados obtidos presentan una boa correlación entre as constantes de asociación en auga e as porcentaxes de PAH extraidas.