Blue Emitting Star-Shaped and Octasilsesquioxane-Based Polyanions Bearing Boron Clusters. Photophysical and Thermal Properties.

ABSTRACT: High boron content systems were prepared by the peripheral functionalisation of 1,3,5-triphenylbenzene (TPB) and octavinylsilsesquioxane (OVS) with two different anionic boron clusters: closo-dodecaborate (B₁₂) and cobaltabisdicarbollide (COSAN). TPB was successfully decorated with three cluster units by an oxonium ring-opening reaction, while OVS was bonded to eight clusters by catalysed metathesis cross-coupling. The resulting compounds were spectroscopically characterised, and their solution-state photophysical properties analysed. For TPB, the presence of COSAN dramatically quenches the fluorescence emission (?_em = 369 nm; ?_F = 0.8%), while B₁₂-substituted TPB shows an appreciable emission efficiency (?_em = 394 nm; ?_F = 12.8%). For octasilsesquioxanes, the presence of either COSAN or B₁₂ seems to be responsible for ?80 nm bathochromic shift with respect to the core emission, but both cases show low emission fluorescence (?_F = 1.4-1.8%). In addition, a remarkable improvement of the thermal stability of OVS was observed after its functionalisation with these boron clusters.

SUBMITTER: Cabrera-Gonzalez J 

PROVIDER: S-EPMC7179457 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature