%A Pereira,Rui F. P.
%A Nunes,Sílvia C.
%A Toquer,Guillaume
%A Cardoso,Marita A.
%A Valente,Artur J. M.
%A Ferro,Marta C.
%A Silva,Maria M.
%A Carlos,Luís D.
%A Ferreira,Rute A. S.
%A de Zea Bermudez,Verónica
%D 2018
%J Frontiers in Chemistry
%C
%F
%G English
%K bis[(3-trimethoxysilyl)propyl]amine,sol-gel chemistry,solvent-assisted structuring,morphology,Luminescence
%Q
%R 10.3389/fchem.2017.00131
%W
%L
%M
%P
%7
%8 2018-January-15
%9 Original Research
%+ Rui F. P. Pereira,Chemistry Center, University of Minho,Portugal,rpereira@quimica.uminho.pt
%+ Prof Verónica de Zea Bermudez,Chemistry Department and CQ-VR, University of Trás-os-Montes e Alto Douro,Portugal,vbermude@utad.pt
%#
%! Novel highly luminescent amine-functionalized bridged silsesquioxanes
%*
%<
%T Novel Highly Luminescent Amine-Functionalized Bridged Silsesquioxanes
%U https://www.frontiersin.org/articles/10.3389/fchem.2017.00131
%V 5
%0 JOURNAL ARTICLE
%@ 2296-2646
%X 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.