Enhancement of Luminescence Properties of CuI based Materials

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Enhancement of Luminescence Properties of Cu(I) Based Materials

Publication . Hosseinzadeh, Mani; Laia, César; Lima, João; Rosa, Vitor

The purpose of this thesis is to investigate the photophysical behaviour of three distinct families of Cu(I) complexes. The distinction is done by three different type of ligands but in all cases the coordination core consists of dinuclear iodide bridged {Cu2(μ-I)2} cluster surrounded by either diimino-, phosphino- or imino-phosphino- (N^N,P,P^N) ligands. All compounds were fully characterized by spectroscopic methods, with special emphasis on their structural features revealed by X-Ray single crystal diffraction and photophysical properties supported by computational calculations. The first family consists of two new complexes bearing α-diimine (Ar-BIAN) ligands functionalized by a nitro group which were compared to the analogue non-functionalized complex. The ground state analysis clarifies the difference between the molecular structures observed within the crystals and the determining role of packing forces. TD-DFT revealed (M+X)LCT (Metal and Halide to Ligand Charge Transfer) absorption bands in the visible with some n→π* character involving stabilized π* orbitals by the presence of NO2. Dynamics of the excited state of all three complexes and of their respective free ligands were examined by Transient Absorption Spectroscopy in the femtosecond time domain allowing to probe the dark states involved in the kinetic pathways followed by excited Cu(I) complexes and the role of ligands structure in the non-radiative decays. The second family includes two new emissive dinuclear Cu(I) complexes bearing terphenyl phosphines. The photophysical behavior of these compounds in liquid solution, solid−solid Zeonex solution and powder samples were investigated at room temperature and 77 K. The steady state and time-resolved emission measurements along with group theory calculations allowed to postulate a luminescence mechanism conditioned by crystal packing. The third family comprised of two new iminophosphine-based complexes, which combine imine and phosphine properties in a sole structure supporting the suggested mechanistic pathways hypothesized for the two first compound families.

2021-12Tese de doutoramento

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Fundação para a Ciência e a Tecnologia

Número da atribuição

SFRH/BD/120985/2016