Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Mar 7;25(5):1210.
doi: 10.3390/molecules25051210.

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

Justo Cabrera-González  1 , Mahdi Chaari  1 , Francesc Teixidor  1 , Clara Viñas  1 , Rosario Núñez  1
Affiliations

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

Justo Cabrera-González et al. Molecules. .

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 (λem = 369 nm; ΦF = 0.8%), while B12-substituted TPB shows an appreciable emission efficiency (λem = 394 nm; ΦF = 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 (ΦF = 1.4-1.8%). In addition, a remarkable improvement of the thermal stability of OVS was observed after its functionalisation with these boron clusters.

Keywords: boranes; boron clusters; luminescence; metallacarboranes; octasilsesquioxanes; triphenylbenzene.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Figures

Scheme 1
Scheme 1
Synthesis of compounds 4 and 5.
Scheme 2
Scheme 2
Synthesis of compounds (a) 6 and (b) T8-B12.
Figure 1
Figure 1
1H-NMR spectra in acetone-d6 of (a) octavinylsilsesquioxane (OVS), (b) compound 6 and (c) T8-B12.
Figure 2
Figure 2
Absorption and emission spectra of (a) 4–5 and (b) T8-B12 and T8-COSAN recorded in CH3CN (au: Arbitrary units).
Figure 3
Figure 3
Thermogravimetric analysis (TGA) data under argon (10 °C/min) for octavinylsilsesquioxane (OVS), T8-B12 and T8-COSAN.
See this image and copyright information in PMC

References

    1. Núñez R., Tarrès M., Ferrer-Ugalde A., Fabrizi de Biani F., Teixidor F. Electrochemistry and Photoluminescence of Icosahedral Carboranes, Boranes, Metallacarboranes, and Their Derivatives. Chem. Rev. 2016;116:14307–14378. doi: 10.1021/acs.chemrev.6b00198. - DOI - PubMed
    1. Mukherjee S., Thilagar P. Boron clusters in luminescent materials. Chem. Commun. 2016;52:1070–1093. doi: 10.1039/C5CC08213G. - DOI - PubMed
    1. Poater J., Solà M., Viñas C., Teixidor F. π Aromaticity and Three-Dimensional Aromaticity: Two sides of the Same Coin? Angew. Chem. Int. Ed. 2014;53:12191–12195. doi: 10.1002/anie.201407359. - DOI - PubMed
    1. Poater J., Solà M., Viñas C., Teixidor F. Back Cover: A Simple Link between Hydrocarbon and Borohydride Chemistries. Chem. Eur. J. 2013;19:4372. doi: 10.1002/chem.201390044. - DOI - PubMed
    1. Kahlert J., Stammler H.-G., Neumann B., Harder R.A., Weber L., Fox M.A. Crystal Structures of the Carborane Dianions [1,4-(PhCB10H10C)2C6H4]2− and [1,4-(PhCB10H10C)2C6F4]2− and the Stabilizing Role of the para-Phenylene Unit on 2 n+3 Skeletal Electron Clusters. Angew. Chem. 2014;126:3776–3779. doi: 10.1002/ange.201310718. - DOI - PMC - PubMed

LinkOut - more resources