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Synthesis, Electronic and Photophysical Properties of 3,8-diaromatic-1,10-phenanthroline Molecules

Year: 2024

Type: article

Abstract: The molecules 3,8-diphenyl-1,10-phenanthroline (L1), 3,8-di(naphthalen-1-yl)-1,10-phenanthroline (L2), 3,8-di(naphthalen-2-yl)-1,10-phenanthroline (L3), 3,8di(anthracen-9-yl)-1,10-phenanthroline (L4), and 3,8-di(pyren-1-yl)-1,10-phenanthroline (L5) were prepared in good yield from the reaction of 3,8-dibromo-1,10phenanthroline with the corresponding boronic acid, catalysed by [Pd(PPh₃)₄].Computational DFT modelling suggests that the aromatic substituent arms are not coplanar with the central phenanthroline (phen) core, and that the HOMO-LUMO gap diminishes as the number of fused carbon rings in the arms increases.Cyclic voltammograms for the ligands show between one and two oxidation and one to three reduction waves, which are believed to be centred on the arms and the central phen fragments, respectively, suggesting some small electronic mixing.The absorption and emission properties depend on the electronic interaction between the polyaromatic substituents and the phenanthroline core.Different emissive ππ* excited states for the molecules bearing anthryl and pyrenyl substituents suggest they have more charge transfer character, and a consequent sensitivity to the increase of solvent polarity.The photosensitizing capacity of singlet oxygen generation upon excitation of L1-L5 in solution is consistent with a significant evolution of the former singlet excited state towards a triplet excited state.

Source: Journal of the Chilean Chemical Society

DOI: 10.4067/s0717-970720240003066188

Authors: José Muñoz, Felipe Peñaloza, Kevin Guajardo, Roxana Arce, Nancy Pizarro, Andrés Vega

Institutions: Universidad Andrés Bello, Center for the Development of Nanoscience and Nanotechnology

Language: English

Topic: Organic Light-Emitting Diodes Research

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: diamond