A General Strategy to Enhance Donor‐Acceptor Molecules Using Solvent‐Excluding Substituents
Conner A. Hoelzel, Hang Hu, Charles H. Wolstenholme, Basel A. Karim, Kyle T. Munson, Kwan Ho Jung, Han Zhang, Yu Liu, Hemant P. Yennawar, John B. Asbury, Xiaosong Li, Xin Zhang
Abstract
While organic donor-acceptor (D-A) molecules are widely employed in multiple areas, the application of more D-A molecules could be limited because of an inherent polarity sensitivity that inhibits photochemical processes. Presented here is a facile chemical modification to attenuate solvent-dependent mechanisms of excited-state quenching through addition of a β-carbonyl-based polar substituent. The results reveal a mechanism wherein the β-carbonyl substituent creates a structural buffer between the donor and the surrounding solvent. Through computational and experimental analyses, it is demonstrated that the β-carbonyl simultaneously attenuates two distinct solvent-dependent quenching mechanisms. Using the β-carbonyl substituent, improvements in the photophysical properties of commonly used D-A fluorophores and their enhanced performance in biological imaging are shown.