Lamellar mono-amidosil hybrids incorporating monomethinecyanine dyes
authors Nunes, SC; Ferreira, CB; Hummer, J; Ferreira, RAS; Carlos, LD; Almeida, P; Bermudez, VD
nationality International
journal JOURNAL OF MATERIALS CHEMISTRY C
keywords ORGANIC-INORGANIC HYBRIDS; NORMAL-ALKYL CHAINS; H STRETCHING MODES; SOLID-STATE LASERS; OPTICAL-PROPERTIES; INFRARED TEMPERATURE; SILICA NANOPARTICLES; MESOPOROUS SILICA; CLAY-MINERALS; GEL MATRICES
abstract Mono-amide cross-linked alkyl-siloxane hybrids synthesized through the sol-gel process and the self-directed assembly have been doped with variable concentrations of monomethinecyanines SSCH2(C6H5)I, SSCH3Cl and SSC2H5ClO4. The host matrix m-A(14) is a lamellar structured hybrid composed of short methyl-capped alkyl chains grafted to the siliceous framework through amide groups. The doped mono-amidosil hybrid materials were obtained as solid powders. The bulky SSCH2(C6H5)I dye inhibited the condensation of the silica network. In the SSCH3Cl- and SSC2H5ClO4-doped m-A(14)-based materials the original lamellar structure coexists with a new lamellar ordered phase with a lower interlamellar distance in which the alkyl chains adopt essentially all-trans conformations. The efficient encapsulation of these two dyes by m-A(14), which ensures their complete dissolution, is due to the coordination of the S atoms of SSCH3Cl and SSC2H5ClO4 to the carbonyl oxygen atoms of the amide cross-links. This process leads to a major breakdown of the disordered and ordered hydrogen-bonded aggregates of m-A(14), but does not affect globally the strength of the hydrogen-bonded array. The most dilute SSC2H5ClO4-doped mono-amidosil studied displays room temperature emission in the visible spectral region (380-680 nm) due to the convolution of the intrinsic emission (blue spectral region) of m-A(14) with that of the SSC2H5ClO4 dye (green and red spectral regions) due to the formation of fluorescent J-dimers. The excitation spectra (monitored along the emission spectra) reveal the occurrence of host-to-monomethinecyanine energy transfer.
publisher ROYAL SOC CHEMISTRY
issn 2050-7526
year published 2013
volume 1
issue 12
beginning page 2290
ending page 2301
digital object identifier (doi) 10.1039/c3tc00515a
web of science category Materials Science, Multidisciplinary; Physics, Applied
subject category Materials Science; Physics
unique article identifier WOS:000315464700003
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journal impact factor 5.976
5 year journal impact factor 5.688
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