1 Aggregation Induced Emission of Gold(I) complexes in water or water mixtures Andrea Pinto, a Noora Svahn, a João Carlos Lima, b and Laura Rodríguez a,c,* a Departament de Química Inorgànica i Orgànica, Secció de Química Inorgànica, Universitat de Barcelona, Martí i Franquès 1-11, E-08028 Barcelona, Spain. E-mail: laura.rodriguez@qi.ub.es. Tel.: +34 93 4039130 b LAQV-REQUIMTE, Dep. Química, Fac. Ciências e Tecnologia, Univ. Nova de Lisboa, Monte de Caparica, Portugal. c Institut de Nanociència i Nanotecnologia (IN 2 UB). Universitat de Barcelona, 08028 Barcelona (Spain) Abstract Gold(I) complexes are an increasing area of investigation due to the possibility of giving rise to supramolecular aggregates with particular and morphologies that can be modulated together with their luminescent properties. A detailed study has been carried out for gold(I) complexes that self-assemble in aqueous medium (in pure water or in mixtures of water with organic solvents in different proportions). The majority of the examples reported until now are found in mixtures of water and DMSO, acetone, DMF or acetonitrile. The addition of cations to a solution of gold(I) complexes has been observed to show a direct impact on the resulting process of aggregation. The use of perhalogenated ligands together with isocyanide moieties should be denoted to promote the resulting self-organization. Nevertheless, other ligands like alkynyls or carbenes also promote self-assembly. A careful analysis of the data shows that aurophilic interactions have a key role in the formation of the resulting aggregates and in the enhancement of the luminescence (aggregation induced emission, AIE). Keywords: Aggregation, emission, water, gold, cations