Synthesis of dye functionalized xerogels via nucleophilic aromatic substitution of fluoro aromatic compounds with aminosilanes

Seifert, Andreas; Ladewig, Katharina; Schönherr, Petra; Hofmann, Katja; Lungwitz, Ralf; Roth, Isabelle; Pohlers, Andreas; Hoyer, W.; Baumann, Gisela; Schulze, Steffen; Hietschold, Michael; Moszner, Norbert; Burtscher, Peter; Spange, Stefan

doi:10.1007/s10971-009-2096-x

Cited by 10 publications

(17 citation statements)

References 37 publications

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“…Similarly to the S-APTES spectrum, the spectrum of S-MPTMS ( Figure 5C) shows signals attributable to the mercaptopropyl group carbon atoms (11.2 ppm (C 1 ), 25.5 ppm (C 2 ), and 22.1 ppm (C 3 )) 36 and signals attributable to unhydrolyzed ethoxy groups or residual ethanol (18.0 and 57.6 ppm). 36,38 The vinyl moiety results in the observation of two resonance peaks (128 and 138 ppm) in the spectrum of the sample S-VTMS ( Figure 5B). 23 Likewise, the phenyl moiety of S-PTMS can be verified by the occurrence of two peaks (at 127 and 133.5 ppm) in its spectrum ( Figure 5D).…”

Section: Resultsmentioning

confidence: 99%

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

et al. 2010

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Organo-functionalized FDU-12 type silicas exhibiting large pore sizes and ordered mesoporous structures were synthesized at low reaction (15°C) and high hydrothermal (160°C) temperatures via the co-condensation of tetraethoxysilane (TEOS) with a suite of organosilanes, i.e., 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropyltrimethoxysilane (MPTMS), vinyltrimethoxysilane (VTMS), and phenyltrimethoxysilane (PTMS), in the presence of structure directing micelles formed using the surfactant pluronic F127 and the pore enlarging reagent trimethylbenzene (TMB). Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) confirmed that all synthesized materials possessed a face-centered cubic mesostructure (space group Fm3 j m), while nitrogen sorption analyses showed that the synthesized materials had extra large pores with cavity sizes of up to 25.4 nm and entrance sizes of up to 10.8 nm. X-ray photoelectron spectroscopy (XPS) and 13 C solid-state magic-angle spinning nuclear magnetic resonance ( 13 C-MAS NMR) measurements verified the incorporation of the different organosilanes into the silica network and more importantly on the inner and outer surfaces of the materials. As-obtained mesoporous silicas were tested in protein immobilization studies using bovine serum albumin and the cellulose-hydrolyzing enzyme cellulase, which in itself is a mixture of three large enzymes. Enzyme immobilization efficiency, activity, and stability varied significantly with organic functionality due to size exclusion effects at pore entries, electrostatic and hydrophobic interactions between the organo-functionalized surfaces and the enzymes, and conformational changes of the enzymes which can occur on some of the material surfaces. As a result, phenyl (PTMS)-and thiol (MPTMS)-functionalized FDU-12 mesoporous silicas had a very low adsorption capacity of proteins because of their small pore sizes. Amino (APTES)-functionalized FDU-12 mesoporous silica showed the highest adsorption amount of proteins yet the lowest activity of immobilized cellulase. Cellulase immobilization on vinyl (VTMS)-functionalized FDU-12 mesoporous silica appeared to be the most promising approach, since it occurred with high efficiency, maintained enzyme activity, and provided temporal enzyme stability.

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Section: Resultsmentioning

confidence: 99%

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

et al. 2010

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“…Since CD complexes of 7 and 8 remain resistant against hydrolysis, the imine chromophores of target polymers should be readily hydrolyzed. As known from a previous study, the imine bases 7 and 8 remain hydrolytic unstable after they have been incorporated in a sol–gel material using NAS with an aminopropyltrialkoxysilane 20. Therefore, it is expected that a related scenario takes place when they do react with PVAm in protic media.…”

Section: Introductionmentioning

confidence: 86%

“…4‐Fluoro‐ N , N ‐dimethyl‐3‐nitroaniline ( 6 ) was synthesized by N , N ‐dimethylation of 4‐fluoroaniline according Giumanini et al as previously described 11c, 21. The fluoro‐substituted schiff bases ( E )‐2‐[(4‐fluoro‐3‐nitrophenylimino)methyl]phenol ( 7 ) and ( E )‐4‐fluoro‐3‐nitro‐ N ‐[(4‐nitrophenyl)methylene]benzamine ( 8 ) were synthesized as previously described 20…”

Section: Methodsmentioning

confidence: 99%

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Influence of the Reaction Conditions and Molecular Structure on the Kinetic of the Nucleophilic Aromatic Substitution of Fluoro Compounds with Poly(vinyl amine) in Water

Hofmann

Roth

Spange

2012

Macro Chemistry & Physics

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The nucleophilic aromatic substitution (NAS) reaction of various fluoroaromatic/2,6‐O‐dimethyl‐β‐cyclodextrin complexes with poly(vinyl amine) (PVAm) has been studied in water at different pH. Increasing pH lowers the notable negative activation entropy of those types of NAS due to the PVAm chain segments becomes better accessible in basic media. At pH > 7, the zwitterionic intermediate in the course of NAS seems stabilized by intermolecular hydrogen bonds, which has an influence on the increase of activation energy for elimination the fluoride ion. As a consequence, the counter balance between activation entropy and activation energy determines the rate of the NAS with PVAm, which is shown for several functional fluoroaromatic compounds including fluoronitrobenzenes, fluoronitroanilines, and imine bases.

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“…This process has the added advantage of improving the wetting and dispersion of the surface of the engineering NPs. In some cases, a passivation layer, e.g., an aminosilane amorphous layer is in contact with the core [71]. 2.4(E)).…”

Section: Gelationmentioning

confidence: 99%

Overviews of Synthesis of Nanomaterials

Bashir

Liu

2015

Advanced Nanomaterials and Their Applications in Renewable Energy

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Synthesis of dye functionalized xerogels via nucleophilic aromatic substitution of fluoro aromatic compounds with aminosilanes

Cited by 10 publications

References 37 publications

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

Influence of the Reaction Conditions and Molecular Structure on the Kinetic of the Nucleophilic Aromatic Substitution of Fluoro Compounds with Poly(vinyl amine) in Water

Overviews of Synthesis of Nanomaterials

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