NEW ORGANOMETALLIC COMPLEXES WITH PHOTOLUMINESCENT AND NON LINEAR OPTICAL PROPERTIES

Owing to their remarkable luminescent properties, organometallic complexes of transition-metals have recently received considerable attention as phosphorescent emitters for Organic Light Emitting Diodes (OLEDs). In particular, various platinum(II) complexes with a cyclometallated 1,3-di(2-pyridyl)benzene ligand seem very promising in this respect because they are highly emissive. These observations prompted us to prepare new cyclometallated Pt(II) complexes with a substituted 1,3-di(2-pyridyl)benzene ligand to get a better understanding of the effect on the emission and quantum yields of different R substituents and various Y ancillary ligands. It turned out that the prepared complexes are highly luminescent showing quantum yields above 50%. Besides, in the last few years organometallic and coordination compounds have also attracted a great deal of attention as chromophores for second-order nonlinear optical (NLO) applications, because they may offer a great diversity of tunable electronic properties by virtue of the metal centre. We have investigated the NLO response of new push-pull anellataed hemicyanine ligands and their related cis-[Ir(CO)2ClL] complexes. NLO properties were determined by the Electric Field Induced Second Harmonic generation (EFISH) technique. These new NLO chromophores are of particular interest since they are characterized by a value higher o fquadratic hyperpolarizability than that of Disperse Red One, an NLO chromophore currently used in electro-optics polymers, and, moreover, they possess particular photostability. We also preliminarily investigated the second-order NLO response of both known and new members of the platinum(II) complexes family above mentioned. This study was conductued by both EFISH and Hyper Light Scattering (HLS) techniques. It turned out that the presence of the PtCl moiety enhances the NLO properties compared to other organic and organometallic compounds. Finally an octupolar tripodal ligand had been prepared which terminates with pyridyl groups that were easily linked to organometallic fragments. Although coordination of our octupolar core to Zn complexes of a commercial porphyrin, or phtalocyanine, did not lead to a substantial improvement in NLO properties, this study puts in evidence the remarkably large second order NLO response of the free Zn-porphyrine itself especially considering its very simple structure and commercially availiability. Details on these studies are presented in this thesis.