authors |
Pereira, RFP; Nunes, SC; Toquer, G; Cardoso, MA; Valente, AJM; Ferro, MC; Silva, MM; Carlos, LD; Ferreira, RAS; Bermudez, VD |
nationality |
International |
journal |
FRONTIERS IN CHEMISTRY |
author keywords |
bis[(3-trimethoxysilyl) propyl] amine; sol-gel chemistry; solvent-assisted structuring; morphology; luminescence |
keywords |
EMISSION RED-SHIFT; MESOPOROUS ORGANOSILICAS; SELF-ORGANIZATION; HYBRID SILICA; SOLVENT; HYDROLYSIS; CONDENSATION; ALKOXYSILANE; MORPHOLOGY; CATALYSTS |
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 = NH2+/= 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. |
publisher |
FRONTIERS MEDIA SA |
issn |
2296-2646 |
year published |
2018 |
volume |
5 |
digital object identifier (doi) |
10.3389/fchem.2017.00131 |
web of science category |
Chemistry, Multidisciplinary |
subject category |
Chemistry |
unique article identifier |
WOS:000419875000001
|
ciceco authors
impact metrics
journal analysis (jcr 2019):
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journal impact factor |
3.693 |
5 year journal impact factor |
4.204 |
category normalized journal impact factor percentile |
68.079 |
dimensions (citation analysis):
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altmetrics (social interaction):
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