An aldehyde functionalized amino-borane has been found to respond to multiple external stimuli such as temperature, pressure and solvents, producing distinct patterns and colours.
A new europium complex coordinated between a Eu(III) ion and an unsymmetrical diarylperfluorocyclopentene yields a light-controlled diarylethene-europium dyad, DAE@TpyEu(tta)3, whose photophysical properties can be reversibly switched by optical stimuli. When DAE@TpyEu(tta)3 is exposed to 365 nm UV light, an efficient intramolecular photochromic fluorescence resonance energy transfer (pc-FRET) occurs between the emission of the Eu(3+) donor (D) and the absorption of the diarylethene acceptor (A) in closed-form DAE@TpyEu(tta)3 accompanied by luminescence quenching. However, the pc-FRET process could be effectively inhibited by visible light (λ > 600 nm) irradiation, and the lanthanide emission of DAE@TpyEu(tta)3 is rapidly recovered. Furthermore, this luminescent lanthanide molecular switch could serve as a highly reliable and sensitive "turn on" fluorescent marker in living cells irradiated by red light without any optical interference.
We herein describe a new design principle to achieve B/N-doped cyclophane where an electron-donor block of three triarylamines (Ar 3 N) and an acceptor block of three triarylboranes (Ar 3 B) are spatially separated on opposite sides of the π-extended ring system. DFT computations revealed the distinct electronic structure of the block-type macrocycle MC-b-B3N3 with a greatly enhanced dipole moment and reduced HOMO-LUMO energy gap in comparison to its analogue with alternating B and N sites, MC-alt-B3N3. The unique arrangement of borane acceptor Ar 3 B and amine donor Ar 3 N components in MC-b-B3N3 induces exceptionally strong intramolecular charge transfer in the excited state, which is reflected in a largely red-shifted luminescence at 612 nm in solution.The respective linear open-chain oligomer L-b-B3N3 was also synthesized for comparison. Our new approach to donor-acceptor macrocycles offers important fundamental insights and opens up a new avenue to unique optoelectronic materials.
Boron
compounds (1–4) containing
an internal B–O bond have been found to undergo facile multistructural
transformations upon irradiation at 365 or 410 nm, generating rare
8-membered B,O-heterocycles (1c–4c). In addition, 2 and 3 also undergo an
intramolecular Diels–Alder addition and oxyborane elimination
concomitantly, via intermediates 2b/3b,
producing 2d/3d. The pathways to isomer c and product d were found to be a thermal process and
a photo process, respectively.
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