Synthesis of luminescent Pt(II) compounds with emissions in the NIR region

Abstract

This Bachelor’s Final Project focuses on the design, synthesis, and photophysical characterization of novel Pt(II) complexes, aiming to evaluate how the metal’s coordination environment modulates phosphorescent emission. These systems play a fundamental role in the development of emerging biomedical and optoelectronic technologies, positioning them at the forefront of current scientific research. The first stage of the project involved the synthesis and characterization of several organic ligands specifically designed for subsequent platinum cyclometallation. The formation of these new compounds was confirmed using 1H NMR and IR spectroscopy. Ultimately, two organometallic complexes with distinct ligand environments were successfully obtained, enabling a comparative analysis of their properties under various conditions. The photophysical study was structured into three main blocks: first, a baseline characterization was conducted using UV-Vis spectroscopy and various emission techniques, including fluorimetry, phophorescence lifetimes, and quantum yields. This was followed by an aggregation study induced by solvent mixtures at a fixed concentration. These experiments demonstrated that the ligand structure is determining factor in the self-assembly capacity of the complex. The results show that, in addition to the high sensitivity of these compounds to oxygen quenching, the choice of ligand is crucial for controlling Pt···Pt interactions, π-π stacking and other possible weak intermoecular contacts. It was confirmed that, under specific solvent and concentration conditions, it is possible to induce or inhibit excimer formation, opening the door to the rational design of materials with tunable emissive properties.