Lamellar mono-amidosil hybrids doped with Rhodamine (B) methyl ester perchlorate
authors Nunes, SC; Freitas, VT; Ferreira, RAS; Carlos, LD; Almeida, P; Bermudez, VD
nationality International
journal JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
author keywords Mono-amide alkyl/siloxane; Self-directed assembly; Sol-gel process; Rhodamine (B) methyl ester perchlorate; Lamellar phases
keywords ORGANIC-INORGANIC NANOCOMPOSITES; NORMAL-ALKYL CHAINS; H STRETCHING MODES; SOLID-STATE LASERS; CHEMILUMINESCENCE DETERMINATION; BRIDGED SILSESQUIOXANES; INFRARED TEMPERATURE; 6G; CONFORMATION; MONOLAYERS
abstract Ordered mono-amide cross-linked alkyl/siloxane hybrids (mono-amidosils) incorporating a Rhodamine (B) methyl ester perchlorate dye (Rh(B) CH3ClO4) have been synthesized through the sol-gel process and self-directed assembly. The host hybrid matrix m-A(14) is a lamellar bilayer hierarchically structured hybrid composed of short methyl-capped alkyl chains grafted to a siliceous framework through amide groups. At low dye concentration [n = 20, where n is the molar ratio of amide groups per Rh(B) CH3ClO4] a new lamellar structure with higher interlamellar distance than that of m-A(14) is formed, whereas at higher dye content (n = 5) this new lamellar structure coexists with that of m-A(14). The efficient encapsulation of Rh(B) CH3ClO4 provided by m-A(14) via hydrogen bonding interactions ensured the complete dissolution of the dye and induced a blue shift of the emission of the dye with respect to that of the isolated state, leading to an increase in the quantum yield from values below 0.01 % (measured for the isolated dye) to 4 % at n = 20. The formation of non-fluorescent H-type dimers in the sample with n = 5 accounts for the reduction of the quantum yield. The incorporation of Rh(B) CH3ClO4) into m-A(14) was clearly beneficial from the standpoint of the dye's photostability, allowing to suppress photobleaching during the first 4 h. An intensification of the emission intensity by 50 and 25 % for the emission centered at 600 and 645 nm resulted, respectively, at n = 20.
publisher SPRINGER
issn 0928-0707
year published 2014
volume 72
issue 2
beginning page 239
ending page 251
digital object identifier (doi) 10.1007/s10971-014-3339-z
web of science category Materials Science, Ceramics
subject category Materials Science
unique article identifier WOS:000343131000006
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