Covalent attachment of 4-amino-1,8-naphthalimides onto the walls of mesoporous molecular sieves MCM-41 and SBA15 (original) (raw)
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Microporous and …, 2007
This work describes the covalent grafting of 3,4,9,10-perylenediimides (PDI), which are fluorescent dyes with very interesting optical properties, onto the walls of mesoporous molecular sieves MCM-41 and SBA-15. The mesoporous materials were first treated with 3-aminopropyltriethoxysilane (APTES) in anhydrous toluene, generating amine-containing surfaces. The amine-containing materials were then reacted with 3,4,9,10-perylenetetracarboxylic dianhydride (PTCA), generating surface-grafted PDI. Infrared spectra of the materials showed that the reaction with amino groups took place at both anhydride ends of the PTCA molecule, resulting in surface attached diimides. No sign of unreacted anhydride groups were found. The new materials, designated as MCMN2PDI and SBAN2PDI, presented absorption and emission spectra corresponding to weakly coupled PDI chromophores, in contrast to the strongly coupled rings usually found in solid PDI samples. The materials showed a red fluorescence, which could be observed by the naked eye under UV irradiation or with a fluorescence microscope. The PDI-modified mesoporous materials showed electrical conductivity when pressed into a pellet. The results presented here show that the new materials are potentially useful in the design of nanowires.
Journal of Luminescence, 2017
The Fe 3 þ-modified 1, 8-naphthalic anhydride (Fe-NA) was prepared, and thereafter successfully grafted on the mesoporous surface of bimodal mesopores material (BMMs) by post-synthesis method. The influence of various parameters, including amount of Fe 3 þ ion, various solvents, different concentrations and loadings of FC-NA on the fluorescence behavior of resultant hybrid materials (FC-NA grafted BMMs) was investigated, and then its fluorescence properties were compared to the parent FC-NA. Meanwhile, their structural properties and photoluminescence performances were investigated using various characterizations XRD, TEM, SEM, SAXS, FT-IR, TGA, ICP-OES, elemental analysis, N 2 adsorption-desorption isotherms, and fluorescence measurement. The results showed that the mesoporous structural integrity was remained intact after introduction of FC-NA in the mesoporous channels of APTES-BMMs. Particularly, SAXS patterns revealed the mass fractal dimension of the hybrid FC-NA@BMMs were gradually increased with increasing loaded amount of FC-NA, and resulted in the uneven distribution and selfsimilarity fractal features. The fluorescence profiles exhibited the occurrence of red-shifts and then blueshifts of characteristic peak with increasing grafted FC-NA amount. These shifts demonstrated a highly aggregation on the amine-modified mesoporous surface of APTES-BMMs when the obtained mass ratio of FC-NA/AP-BMMs was lower than 0.2, whereas a uniform monodispersion distribution was observed when the mass ratio got higher than 0.2. The obtained functionalized mesoporous materials with enhanced fluorescence intensity have a potential application in drug sustained/controlled delivery systems.
Behavior of fluorescent molecules bound to the interior of silica nanocapsules in various solvents
Journal of Colloid and Interface Science, 2009
Porous silica nanocapsules with 20% 3-aminopropyltrimethoxysilane (APS)-bound 6-carboxy-fluorescein (APS-fluorescein) and 80% APS molecules adsorbed on the surface of a 50-nm-diameter Au core were prepared by a modified core-shell method. Silica mesoporous nanocapsules were obtained after the Au cores were dissolved in sodium cyanide. The size of the pores in the silica shells corresponded to the area of the fluorescein (approximately 1.02 nm 2 ) in each APS-fluorescein molecule, which was bound to the silica shell by coupling between the silanol groups of APS in the APS-fluorescein molecule and the silica shell. The amino group of APS bound to the silica inside the shell is also reactive. Dy485XL N-hydroxysuccinimide ester (NHS) molecules were then added to the mesoporous silica nanocapsules in the solution and bonded to the amino group of the interior. Thus, mesoporous (fluorescein and Dy485XL)-bound silica nanocapsules were obtained. The fluorescence of Dy485XL was only observed in the mesoporous (fluorescein and Dy485XL)-bound silica nanocapsules in aqueous solution after ultrafiltration. However, the fluorescence of fluorescein reappeared after the addition of acetonitrile. Furthermore, upon adding various solvents to the mesoporous (fluorescein and Dy485XL)-bound silica nanocapsules, their fluorescence varied with that of fluorescein or Dy485XL. In the case of a mixture of 6-carboxy-fluorescein-N-hydroxysuccinimide (FLUOS) and Dy485XL-NHS free molecules in aqueous solution, the fluorescence of FLUOS was observed. Such different fluorescence phenomena demonstrated that Dy485XL-NHS molecules can easily penetrate into the nanocapsule interior via the pores and that the interior of the silica nanocapsules can bind to Dy485XL molecules. These fluorescence behaviors are discussed in terms of fluorescence resonance energy transfer (FRET) and solvatochromism.
Langmuir, 2008
We describe here a method for study of bulk release and local molecular transport within mesoporous silica spheres. We have analyzed the loading and release of charged fluorescent dyes from monodisperse mesoporous silica (MMS) spheres with an average pore size of 2.7 nm. Two different fluorescent dyes, one cationic and one anionic, have been loaded into the negatively charged porous material and both the bulk release and the local molecular transport within the MMS spheres have been quantified by confocal laser scanning microscopy. Analysis of the time-dependent release and the concentration profiles of the anionic dye within the spheres show that the spheres are homogeneous and that the release of this nonadsorbing dye follows a simple diffusion-driven process. The concentration of the cationic dye varies radially within the MMS spheres after loading; there is a significantly higher concentration of the dye close to the surface of the spheres (forming a "skin") compared to that at the core. The release of the cationic dye is controlled by diffusion after an initial period of rapid release. The transport of the cationic dye within the MMS spheres of the dye from the core to near the surface is significantly faster compared to the transport within the surface "skin". A significant fraction of the cationic dye remains permanently attached to the negatively charged walls of the MMS spheres, preferentially near the surface of the spheres. Relating bulk release to the local molecular transport within the porous materials provides an important step toward the design of new concepts in controlled drug delivery and chromatography.
Microporous and Mesoporous Materials, 2007
This work describes the encapsulation of N,N 0 -bis(2-phosphonoethyl)-3,4,9,10-perylenetetracarboxylic diimide (PPDI), a water-soluble perylene dye, in the channels of mesoporous silica MCM-41. The incorporation of the dye was achieved by stirring MCM-41 with aqueous solutions of PPDI. The solid material obtained by this process exhibited a red fluorescence. Diffuse reflectance and emission spectra of the fluorescent powder suggested a highly organized arrangement with the PPDI molecules self-assembled in a 1D stack inside the channels of the mesoporous silica. The new materials described here have potential applications as nanoscale optoelectronic devices, such as conducting nanowires and fluorescent gas sensors.
2021
Here we report the synthesis of two morpholino-substituted naphthalimide ligands, N-(3-picolyl)-4-(1-morpholino)-1,8-naphthalimide L1 and N-benzyl-4-(1-morpholino)-1,8-naphthalimide L2, and study their supramolecular properties in the crystalline, solution and gel phases. These ligands were designed through incorporation of the morpholino group to enhance their photophysical and pH-responsive properties following recently reported N-(3-picolyl) naphthalimide metallogels. L1 was found to form metallogels on reaction with either Mn2+ or Co2+. The gels were found to be thermally and chemically responsive to various stimuli including pH. Conversely, L2 showed no reaction or coordination with transition metals, and did not gel under analogous conditions to L1. In the solution state, the fluorescence of both L1 and L2 exhibited pH responsiveness and counterion-influenced aggregation. The microparticle formation over the pH range was further investigated through Dynamic Light Scattering an...
Spherical Silica Functionalized by 2-Naphthalene Methanol Luminophores as a Phosphorescence Sensor
International Journal of Molecular Sciences, 2021
Photoluminescence is known to have huge potential for applications in studying biological systems. In that respect, phosphorescent dye molecules open the possibility to study the local slow solvent dynamics close to hard and soft surfaces and interfaces using the triplet state (TSD: triplet state solvation dynamics). However, for that purpose, probe molecules with efficient phosphorescence features are required with a fixed location on the surface. In this article, a potential TSD probe is presented in the form of a nanocomposite: we synthesize spherical silica particles with 2-naphthalene methanol molecules attached to the surface with a predefined surface density. The synthesis procedure is described in detail, and the obtained materials are characterized employing transmission electron microscopy imaging, Raman, and X-ray photoelectron spectroscopy. Finally, TSD experiments are carried out in order to confirm the phosphorescence properties of the obtained materials and the route ...