Photoluminescence in m-carborane–anthracene triads: a combined experimental and computational study

Abstract

m-Carborane has demonstrated to be a perfect platform to boost the fluorescence properties of anthracene, giving rise to high fluorescence quantum yields in solution and also retaining fluorescence emission in the aggregate state.

Efficient blue light emitting materials based on m-carborane–anthracene dyads. Structure, photophysics and bioimaging studies

“…2a), which can be assigned to the LE emission of the anthracene moiety. As for the previous compounds reported by us, 19 the similarity between the spectra of 4-6 in solution and that of anthracene (λ em = 420 nm) suggests that small electronic interactions between the anthracene units take place, and there is no influence of the iodine atom. Remarkably, compounds 4-6 exhibit extraordinary high fluorescence quantum yield values (ϕ F ) in solution that are around 100%.…”

“…The synthesis of compounds 4-6 was achieved by nucleophilic substitution at one C c atoms, 20 following a similar procedure to that used for the previous o-and m-carborane derivatives. 16,17,19 Compound 4 was obtained by the nucleophilic substitution of 1,7-closo-C 2 B 10 H 12 (1), whereas 5 and 6 were obtained from the respective mono-and di-iodinated derivatives, 9-I-1,7-closo-C 2 B 10 H 11 (2) and 9,10-I 2 -1,7-closo-C 2 B 10 H 10 (3), which were previously prepared by electrophilic substitution at the B atoms. 21 The key step for the preparation of compounds is the monolithiation of starting compounds 1-3, which was efficiently performed using THF as a solvent under diluted conditions at 0°C; then the reaction of the corresponding monolithium salts with one equiv.…”

“…The molecular structures for all these compounds show typical icosahedral geometry with very similar bond distances and angles, which are also similar to those in anthracenyl-disubstituted m-carborane compounds. 19 In all structures, the m-carborane moiety is linked to one anthracene unit through a methylene spacer (-CH 2 -). As shown in Fig.…”

“…18 Noticeably, m-carboraneanthracene triads obtained by linking two anthracene units to the m-carborane fragment exhibited a significant increase in more than two-fold in the intrinsic fluorescence quantum yield of the anthracene in solution as well as a red-shift of the emission maximum and moderate quantum efficiencies in the aggregate state. 19 Nevertheless, the differences in the ϕ F values obtained for different triads in the aggregate state were attributed to the arrangement of dimers in the solid state structures; it was concluded that the presence of a large number of BH⋯I contacts leads to a less delocalized system for the diiodo derivative, and therefore a lower quantum yield value.…”

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

“…The interest in carboranes and metallacarboranes as potential units for molecular materials might be endorsed to their remarkable chemical, thermal, and biological stabilities [7][8][9][10][11][12][13][14][15][16][17]. Owing to the properties above of carboranes, they have been used as exceptional building blocks for developing a large variety of fluorescent carborane-containing molecules, in which the cluster is usually linked to a fluorescent π-conjugated organic system, either directly by the C c [18][19][20][21][22][23][24][25][26][27][28][29][30] or through one spacer [7][8][9][31][32][33][34][35][36][37][38][39].…”