AUTHOR=Pandey Umesh Pratap , Nandi Rajendra Prasad , Thilagar Pakkirisamy 

TITLE=Design, Synthesis, and Temperature-Driven Molecular Conformation-Dependent Delayed Fluorescence Characteristics of Dianthrylboron-Based Donor–Acceptor Systems

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.541331

DOI=10.3389/fchem.2020.541331

ISSN=2296-2646

ABSTRACT=<p>We report a simple and novel molecular design strategy to enhance rISC in boron-based donor–acceptor systems to achieve improved delayed fluorescence characteristics. Dianthrylboryl ((An)<sub>2</sub>B)-based aryl aminoboranes <bold>1</bold> (donor: phenothiazine) and <bold>2</bold> (donor: N,N-diphenylamine) were synthesized by a simple one-pot procedure. The energy of the electronic excited states in <bold>1</bold> and <bold>2</bold> were modulated by varying the arylamine donor strength and electronic coupling between D and A moieties. The presence of a large π-system (anthryl moiety) on boron enhances the electronic communication between donor arylamine and acceptor boryl moieties, and hence, both <bold>1</bold> and <bold>2</bold> exhibit delayed fluorescence characteristics in a broad range of temperatures (80–300 K). Single crystal X-ray analysis and temperature-dependent photophysical studies together with theoretical studies were carried out to rationalize the observed intriguing optical signatures of <bold>1</bold> and <bold>2</bold>.</p>