Effect of Nitro Group Location on the Optical Properties of Pyrrolidinone-Fuse-1,2-Azaborine Chromophores
Disciplines
Materials Chemistry | Organic Chemistry | Physical Chemistry
Abstract (300 words maximum)
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.
Academic department under which the project should be listed
CSM - Chemistry and Biochemistry
Primary Investigator (PI) Name
Carl Saint-Louis
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.