Effect of Nitro Group Location on the Optical Properties of Pyrrolidinone-Fuse-1,2-Azaborine Chromophores
Primary Investigator (PI) Name
Carl Saint-Louis
Department
CSM - Chemistry and Biochemistry
Abstract
Polycyclic aromatic compounds substituted with the -NO2 moiety are commonly used in n-type organic conjugates due to the strong electron accepting capabilities of the -NO2 group. However, adding a -NO2 group to chromophore’s scaffold quenches their fluorescence, particularly in polycyclic aromatic compounds containing three coordinated boron, such as pyrrolidinone-fuse-1,2-azaborines (PFAs). Due to strong intermolecular π-π stacking interactions, these NO2-substituted PFAs tend to aggregate at high concentrations, causing emission quenching, also known as aggregation-caused quenching (ACQ). In this study, we synthesized four PFAs substituted with a -NO2 group at positions (1-, 2-, 3-, and 4-) to investigate the influence of the location of the -NO2 group on the optical properties. Unexpectedly, the location of the -NO2 group to the left hemisphere of the PFA core results in distinct optical properties. Substitution of the -NO2 group at different position also resulted in aggregation-induced emission (AIE), aggregation-caused quenching (ACQ) or both in a single PFA scaffold. We further noticed solvatochromic and thermochromic properties based on the substitution of –NO2 group to the left hemisphere of the PFA.
Disciplines
Materials Chemistry | Organic Chemistry | Physical Chemistry
Effect of Nitro Group Location on the Optical Properties of Pyrrolidinone-Fuse-1,2-Azaborine Chromophores
Polycyclic aromatic compounds substituted with the -NO2 moiety are commonly used in n-type organic conjugates due to the strong electron accepting capabilities of the -NO2 group. However, adding a -NO2 group to chromophore’s scaffold quenches their fluorescence, particularly in polycyclic aromatic compounds containing three coordinated boron, such as pyrrolidinone-fuse-1,2-azaborines (PFAs). Due to strong intermolecular π-π stacking interactions, these NO2-substituted PFAs tend to aggregate at high concentrations, causing emission quenching, also known as aggregation-caused quenching (ACQ). In this study, we synthesized four PFAs substituted with a -NO2 group at positions (1-, 2-, 3-, and 4-) to investigate the influence of the location of the -NO2 group on the optical properties. Unexpectedly, the location of the -NO2 group to the left hemisphere of the PFA core results in distinct optical properties. Substitution of the -NO2 group at different position also resulted in aggregation-induced emission (AIE), aggregation-caused quenching (ACQ) or both in a single PFA scaffold. We further noticed solvatochromic and thermochromic properties based on the substitution of –NO2 group to the left hemisphere of the PFA.