Cyclometalated platinum(II) diimine complexes: synthetically tuning the photophysical and electrochemical properties
Presented is the synthesis of an array of 16 heteroleptic phosphorescent diimine complexes of platinum(II) with electronically diverse ligand spheres and their full spectroscopic, photophysical, and electrochemical characterization. The complexes were found to exhibit luminescence (480–500 nm) in deaerated solutions at room temperature from a long-lived 3LC state (τ = 2–3 μs) that exhibits significant metal character perturbed by a low-lying 1MLCT state. Interestingly, emission from a 3MLCT state was not observed as is the case with many other polypyridine-based d-block complexes. Electrochemical intermediates proved stable as multiple reversible reductions between −1 and −2 V vs. SCE were noted during cyclic voltammetry experiments unveiling the potential of these luminophores for use in a variety of optoelectronic and solar energy conversion applications.