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https://hdl.handle.net/10316/107607
Title: | Novel Highly Luminescent Amine-Functionalized Bridged Silsesquioxanes | Authors: | Pereira, Rui F. P. Nunes, Sílvia C Toquer, Guillaume Cardoso, Marita A Valente, Artur J. M. Ferro, Marta C. Silva, Maria M. Carlos, Luís D. Ferreira, Rute A. Sá de Zea Bermudez, Verónica |
Keywords: | bis[(3-trimethoxysilyl)propyl]amine; luminescence; morphology; sol-gel chemistry; solvent-assisted structuring | Issue Date: | 2017 | Publisher: | Frontiers Media S.A. | Project: | POCI-01-0145-FEDER-007491 UID/Multi/00709/2013) UID/QUI/00616/2013 POCI-01-0145-FEDER-016422 POCI-01-0145- FEDER-016884 SFRH/BPD/63152/2009 SFRH/BPD/87759/2012 POCI-01-0145- FEDER- 007679 UID/CTM/50011/2013 |
Serial title, monograph or event: | Frontiers in Chemistry | Volume: | 5 | Abstract: | Amine-functionalized bridged silsesquioxanes (BSs) were synthesized from bis[(3-trimethoxysilyl)propyl] amine via a solvent-mediated route. BS-1 and BS-2 were obtained at neutral pH with sub- and stoichiometric amounts of water, respectively, and high tetrahydrofuran content. BS-3 was prepared with hyperstoichiometric water concentration, high tetrahydrofuran content, and hydrochloric acid. BS-4 was synthesized with hyperstoichiometric water concentration, high ethanol content, and sodium hydroxide. BS-1 and BS-2 were produced as transparent films, whereas BS-3 and BS-4 formed white powders. Face-to-face stacking of flat or folded lamellae yielded quasi-hydrophobic platelets with emission quantum yields of 0.05 ± 0.01 (BS-1 and BS-2) or superhydrophilic onion-like nanoparticles with exciting emission quantum yields of 0.38 ± 0.03 (BS-3) and 0.33 ± 0.04 (BS-4), respectively. The latter two values are the largest ever reported for amine-functionalized siloxane-based hybrids lacking aromatic groups. Fast Grotthus proton hopping between = [Formula: see text]/ = NH groups (BS-3) and = N-/ = NH groups (BS-4), promoted by H+ and OH- ions, respectively, and aided by short amine-amine contacts provided by the onion-like morphology, account for this unique optical behavior. | URI: | https://hdl.handle.net/10316/107607 | ISSN: | 2296-2646 | DOI: | 10.3389/fchem.2017.00131 | Rights: | openAccess |
Appears in Collections: | FCTUC Química - Artigos em Revistas Internacionais |
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