Optoelectronic Properties of Carbon-Bound Boron Difluoride Hydrazone Dimers |
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Authors: | Daniela Cappello Dr Ryan R Maar Prof?Dr Viktor N Staroverov Prof?Dr Joe B Gilroy |
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Institution: | Department of Chemistry, and Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, London, Ontario, N6A 5B7 Canada |
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Abstract: | The creation of dimeric boron difluoride complexes of chelating N-donor ligands is a proven strategy for the enhancement of the optoelectronic properties of fluorescent dyes. We report dimers based on the boron difluoride hydrazone (BODIHY) framework, which offer unique and sometimes unexpected substituent-dependent absorption, emission, and electrochemical properties. BODIHY dimers have low-energy absorption bands (λmax=421 to 479 nm, ?=17 200 to 39 900 m ?1 cm?1) that are red-shifted relative to monomeric analogues. THF solutions of these dimers exhibit aggregation-induced emission upon addition of water, with emission enhancement factors ranging from 5 to 18. Thin films of BODIHY dimers are weakly emissive as a result of the inner-filter effect, attributed to intermolecular π-type interactions. BODIHY dimers are redox-active and display two one-electron oxidation and two one-electron reduction waves that strongly depend on the N-aryl substituents. These properties are rationalized using density-functional theory calculations and X-ray crystallography experiments. |
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Keywords: | aggregation-induced emission boron–nitrogen heterocycles cyclic voltammetry electronic structure calculations X-ray crystallography |
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