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

Abstract

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) 2 B)-based aryl aminoboranes 1 (donor: phenothiazine) and 2 (donor: N,N-diphenylamine) were synthesized by a simple one-pot procedure. The energy of the electronic excited states in 1 and 2 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 1 and 2 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 1 and 2.

Ultralong room temperature phosphorescence and ultraviolet fluorescence from simple triarylphosphine oxides

“…We have been involved in developing RTP materials for the last one decade. [33][34][35][72][73][74][75][76][77][78][79] As part of the ongoing program, we set to investigate the RTP characteristics of a series of simple triarylphosphines (1, 2, 3, and 4) and triarylphosphine oxides (5, 6, 7, and 8) to gain an understanding on how different are the lone pair electrons in R 3 P compared to arylphosphanediamines in the production of triplet excitons through np* transitions, and to understand the difference between R 3 P and R 3 P(O) based np* transitions in the production of triplet excitons. For this study, we synthesized a series of arylphosphines and arylphosphine oxides (Scheme 1).…”

Molecular Persistent Room-Temperature Phosphorescence from Tetraarylaminoboranes

“…At ambient conditions, the prompt (λ em = 475 nm and τ av = 10 ns) and delayed spectra (delay time = 50 μs, λ em = 475 nm, and τ av = 5.12 μs) of 1 overlap smoothly (Figure a). Furthermore, the time-resolved decay kinetics show nanosecond and microsecond lifetimes, respectively, for prompt and delayed emission bands, which is typical of DF …”