Multicomponent nanocrystals have become an important type of materials due to their ability to carry out multiple functions simultaneously. In this direction, colloidal synthesis allows to prepare nanoparticles (NPs) with a high level of control over size, geometry, phase and composition. Therefore the development of nanoparticles by colloidal synthesis is beginning to be used for the preparation and study of new catalysts, because their properties are strongly correlated with the design of their active centers. Additionally, catalysts based on well-dispersed colloidal nanoparticles, the so-called semiheterogeneous systems, combine the advantages of both homogeneous and heterogeneous catalysts.
In this contribution we present the preparation of Pd2Sn and Au-Pd2Sn nanoparticles and the study of their catalytic behavior in hydrogenation and coupling reactions. Starting from Pd2Sn nanorods (NRs),1 Au-Pd2Sn heteronanorods (HNRs) were synthesized by a seed-mediated growth method.2 In order to obtain a thorough characterization of the HNRs and gain mechanistic insight into the Au growing process, TEM, HRTEM, XRD and XPS have been performed (Figure 1).
The nanoparticles are active in hydrogenation of aromatic alkenes and alkynes under mild conditions, with an Au-effect on the catalytic outcome.3,4 The nanoparticles have also been tested in Sonogashira reactions.5 At low concentrations good activities towards the coupling product have been found. Unexpectedly, at high concentrations this product is catalytically reduced (Figure 2). Our preliminary study of the mechanism seems to indicate that the NPs also catalyze this reduction step without the involvement of molecular hydrogen.
1) Luo, Z.; Ibáñez, M.; Antolín, A. M.; Genç, A.; Shavel, A.; Contreras, S.; Medina, F.; Arbiol, J.; Cabot, A. Langmuir, 2015, 31 (13), 3952–3957.
(2) Krylova, G.; Giovanetti, L. J.; Requejo, F. G.; Dimitrijevic, N. M.; Prakapenka, A.; Shevchenko, E. V. J. Am. Chem. Soc., 2012, 134 (9), 4384–4392.
(3) Wu, Y.; Cai, S.; Wang, D.; He, W.; Li, Y. J. Am. Chem. Soc., 2012, (134), 8975−8981.
(4) González de Rivera, F.; Angurell, I.; Rossel, D.M.; Erni, R.; Llorca, J.; Divins, J.N.; Muller, G.; Seco, M.; Rossell,O. Chem. Eur.J., 2013, 19 (36), 11963–11974.
(5) González-Arellano, C.; Abad, A.; Corma, A.; García, H.; Iglesias, M.; Sánchez, F. Angew.Chem.Int.Ed, 2007, (119), 1558–1560.
