The advances in boron incorporated organics have captured overwhelming interest on account of their outstanding properties and promising applications in various fields. Mostly, triarylborane compounds (TAB) are exploited as sensors of F and CN anions at the expense of the intrinsic Lewis acidic nature of boron. New molecular probes 1 and 2 for detection of toxic thiophenol were designed by conjugating highly fluorescent borylanilines with the luminescent quencher 2,4-dinitrobenzene based sulfonamides (DNBS), wherein the electrophilicity of the DNBS moiety has been modulated by fine-tuning the intrinsic Lewis acidity of boron. The interplay between PET (photoinduced electron transfer) and ICT have been employed for developing the TAB tethered turn-on fluorescent sensor for thiophenol with high selectivity for the first time. The newly developed probes showed very fast response toward thiophenol (within ∼5 min) with limits of detection (LOD) lying in the micromolar range, clearly pointing to their potential. Further, compounds 1 and 2 were explored for detecting thiophenol in the intracellular environment by discriminating biothiols. DFT and TD-DFT calculations were performed to support the sensing mechanism.

Understanding the structure−property and structure− morphology correlations of organic luminescent materials is essential in order to employ such materials for desired applications. In this regard, we prepared a library of novel triarylboron-tethered N-boryl-1,8naphthalimides (TAB-NPIs) 1−6 with variations in their steric and electronic factors. Compounds 1−6 are weakly luminescent in molecularly dispersed state; however, they are strongly luminescent in the aggregated state (THF−H 2 O mixture). The presence of sterically hindered triarylboryl units in 1−6 endowed these molecules with aggregation-induced emission (AIE) characteristics by preventing cofacial arrangements of NPI moieties, as shown by the supramolecular interactions in the crystal lattice. These structural features preclude excimer formation which can be detrimental to the radiative process in these molecules. Promisingly, these compounds undergo self-assembly and form interesting morphologies such as sheets (1), fibers (2), tubes (3), vesicles (4), flowers (5), and porous films (6). These types of morphologies are rarely observed in purely organic materials; evidently, the morphology of these compounds strongly depends on their molecular conformations and steric and electronic factors.

Reported herein are the synthesis, structure, and intriguing optical characteristics of four new polyaromatic aminoboranes (1−4) bearing dimesitylboron (Mes 2 B) as electron-accepting unit(s) and diphenylamine (Ph 2 N) as electron-donating unit(s). These compounds are strongly fluorescent in the solid state. Crystalline samples of 1 and triarylboranedecorated aminoboranes 3 and 4 were found to be blue emitters in the solid state. Compounds 1 and 2 showed aggregation-induced emission (AIE) and aggregation-induced emission color switching, respectively, while 3 and 4 exhibited aggregation-induced emission enhancement. Compounds 1 and 2 showed fascinating mechanofluorochromism upon grinding, and such fluorescence changes are due to a crystalline−amorphous phase transition, as confirmed by powder X-ray diffraction studies (PXRD). Interestingly, a ground sample of 2 was found to be stable and did not revert back upon removal of external stress even after the sample was kept over a long period of time under ambient conditions (more than 6 months). "IPC" was written on a substrate of 2, and the part that was touched showed fluorescence different from the rest of the substrate, which could be erased by heating, demonstrating its capability for rewritable data storage devices. The effect of steric and electronic factors on the optical properties of molecules was corroborated by DFT computational studies.

A donor-π-acceptor strategy is being well exploited in several fields in view of their robust optical properties. However, the impact of branching in quadrupolar [A-(π-D) 2 ] and octupolar [A-(π-D) 3 ] molecules in comparison to parent dipolar (A-π-D) molecules on the delayed fluorescence and phosphorescence properties is seldom explored. We have presented herein the distinct and contrasting optical properties of a tridurylborane core bearing −NH 2 (1−3) and −NMe 2 (4−6) donor moieties, wherein the number of donors is increased systematically. Because of propeller molecular architecture, the donor and acceptor are weakly coupled, and the frontier molecular orbitals are spatially localized. All of the compounds show delayed fluorescence under ambient conditions and persistent phosphorescence at low temperature. Solvent-dependent studies and temperaturedependent luminescence measurements established that quadrupolar (2 and 5) and octupolar (3 and 6) compounds underwent symmetry breaking in the excited state. Curiously, delayed fluorescence and phosphorescence spectra are found to be blue-shifted and follow the same trend as the fluorescence upon an increase in the branches. The highest quantum yield was observed for dipolar compounds. Besides, the phosphorescence lifetime decreases with an increase in the number of branches. These interesting experimental observations are further supported by quantum-mechanical calculations.

Herein, the design,s ynthesis, optical properties, and mechanofluorochromism characteristics of as eries of conjugates having covalently linked triarylborane (TAB) and anil/boranil units (TAB-anil: 1a-3a and TAB-boranil: 1-3)a re reported. The electronic interactions between TABa nd anil/ boranili n1a-3a and 1-3 were fine-tuned by changing the boryl moiety's positiono nt he phenyls pacer connecting the BMes 2 (Mes = mesityl)a nd anil/boranil units.Ab oryl moiety at the meta position(1a)o ft he phenyl spacers tabilizest he enolic form (E-OH), whereas ab oryl moiety at the para position (2a and 3a)s tabilizes the keto form (Z-NH) in the solid state.H owever,i ns olution 1a, 2a,a nd 3a exhibit keto-enol tautomerism in both ground and excited states.C ompounds 1a-3a and 1-3 show red-shifted absorption compared with 4a and 4,which are devoid of TABmoieties, which indicate effectivep articipation of an empty po rbital on the boronc enteri n1a-3a and 1-3.C ompounds 1 and 2 showed fluorescence variations in response to externals timuli such as mechanical grinding. Long phosphorescence lifetimes of 18-46 ms were observed for compounds 1-3.T he observed optical properties of 1a-3a and 1-3 are rationalized in the context of quantumm echanical calculations.