Diseño y síntesis de ligandos orgánicos para el desarrollo de nuevos complejos de paladio, platino y plata con nuevas propiedades ópticas y electrónicas

Resumo

This PhD Thesis report entitled “Design and synthesis of organic ligands for developing new palladium, platinum and silver complexes with new optic and electronic properties” is divided in two parts. First part is related with chiroptical properties of simple organic molecules (SOM). Nowadays, considerable interest of photochemistry has been focused on circularly polarized luminescence (CPL), which is dissymmetric emission of right- and left-handed circularly polarized light from chiral substances, due to the potential applications in many fields such as 3D display and chiral molecular-tag. In addition, CPL is a very powerful tool for structural analysis of excited states as it is markedly enhanced with excitonic-coupling interactions among two or more chromophore units at the excited states. Since obtaining simple organic molecules with high CPL signal is still challenging, one of the goals is CPL active substances with high dissymmetry factor (glum). This initial part is divided in three chapters; first one is based on synthesis and chiroptical properties evaluation of orto-oligophenylethynylenes (o-OPE) foldamers with sulfoxide as chiral inductor and the effect of metal coordination in these properties. Chapter 2 is related with synthesis and chiroptical characterization of stapled o-OPEs which are more stable and CPL active than previous structures. A main o-OPE scaffold is designed in order to evaluate the chiroptical properties in derivatives with steric effect groups or chromophores like pyrene that allows to build a ratiometric probe. In addition, longer helix structures which lead to higher CPL signals are considered. Last, chapter 3 focuses on combined CPL and two photon absorption (TPA). Synthesis of molecules with different combined properties is an interesting approach for the development of new materials. A new simple molecule based on a chiral cyclohexane and perylendiimides (PDI) is synthesized in order to obtain a combined CPL and TPA compound. Second part addresses the electronic properties in molecular wires. Scanning tunneling microscope (STM) is mainly used in this part with the aim of measure the unimolecular conductance of the compounds. The introduction discusses about different aspects of the electronic circuit and the relationship between chemical structure and property, also most important applications of these devices are commented. The main objective of this part with just one chapter is measuring electronic properties of nitrogen-metal-carbon bonds in palladium complexes to shed light about the behaviour of conductance in this kind of structures. In conclusion, we shed light about chiroptical and electronic properties in different SOM and we have developed some molecules with potential applications using CPL. 1a) M. C. Heffern, L. M. Matosziuk, T. J. Meade, Chem. Rev. 2014, 114, 4496-4539. b) F. Zinna, M. Pasini, F. Galeotti, C. Botta, L. di Bari, U. Giovanella, Adv. Funct. Mater. 2017, 27, 1603719-1603726. 2H. Tanaka, Y. Inoue, T. Mori, ChemPhotoChem, 2018, 2, 386-402. 3T. A. Su, M. Neupane, M. L. Steigerwald, L, Venkataraman, C. Nuckolls, Nature Rev. Mater. 2016, 1, 16002.