13C- and 1H-NMR and FTIR spectroscopic evidence for aggregate formation of organosilanes in toluene

Shimizu, Ichiro; Okabayashi, Hirofumi; Hattori, Norikatsu; Taga, Keijiro; Yoshino, Atsuo; O’Connor, Charmian J.

doi:10.1007/s003960050084

Cited by 18 publications

(18 citation statements)

References 10 publications

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“…It turns out that probably the 3-APTS is forming agglomerates in the bulk of the liquid phase, and it is known from 29 Si-NMR and Fourier transform spectroscopy studies that polymerization to form siloxane bonds between adsorbing species often accompanies surface adsorption. 26,27 Indeed, Shimizu et al have reported that 3-APTS forms micelles in toluene solution: NMR measurements of critical micelle concentration estimated a value of 0.47 M. 26 Therefore, we shift our attention to the more dilute solutions (3.0 mM) in order to obtain flatter and more organized modified surfaces.…”

Section: Resultsmentioning

confidence: 98%

Surface chemistry of the iron tetraazamacrocycle on the aminopropyl‐modified surface of oxidized n‐Si(100) by AFM and XPS

Magalhães

Moreira

Rodrigues-Filho

et al. 2002

Surface & Interface Analysis

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The structure and formation mechanisms of 3-aminopropyltrimethoxysilane (3-APTS) films deposited on wet-chemically grown silicon dioxide over n-Si(100) wafer have been examined systematically using x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The asymmetric N 1s XPS spectrum for the anchored 3-APTS was fitted for -NH 2 (399.6 ± 0.3 eV) and -NH 3 + (401.1 ± 0.3 eV). Rougher surfaces are obtained by deposition from toluene solutions than from the gaseous phase. Over the 3-APTS layer was deposited the [FeTIM(CH 3 CN) 2 ]2+ complex, where TIM is 2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene. The adsorption occurs by acetonitrile replacement for the-NH 2 -grafted group with the equatorial plane parallel to the organomodified surface. Once FeTIM can bind a CO, NO or N-heterocycle, a built-on Si wafer sensor device could be envisaged for these molecules.

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Section: Resultsmentioning

confidence: 98%

Surface chemistry of the iron tetraazamacrocycle on the aminopropyl‐modified surface of oxidized n‐Si(100) by AFM and XPS

Magalhães

Moreira

Rodrigues-Filho

et al. 2002

Surface & Interface Analysis

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“…This is also the case for the IR spectra of dilute toluene solutions of APTES where the ν sym,asym (NH) bands are located at higher frequency regions (respectively 3324 and 3384 cm -1 ) (Shimizu et al 1997). If alkylammonium cations were formed in samples C-E, they would have exhibited several characteristic absorption bands in the 2500-2800 cm -1 region and a band of medium intensity at ca.…”

Section: The Structure Of the Surface Layer In The Synthesized Xerogelsmentioning

confidence: 99%

Structural Features of Surface Layers of Bifunctional Polysiloxane Xerogels Containing 3-Aminopropyl Groups and 3-Mercaptopropyl Groups

Zub

Melnyk

White

et al. 2008

Adsorption Science & Technology

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Polysiloxane xerogels containing both -SH and -NH 2 functions have been prepared using the sol-gel method with alkoxysilane precursors [such as Si(OEt) 4 , (MeO) 3 Si(CH 2 ) 3 SH and (EtO) 3 Si(CH 2 ) 3 NH 2 ]. Molar ratios of 3.2:1, 1.1:1 and 0.4:1 for the two functions -SH and -NH 2 were employed. Xerogels which contain only one of the two functions were also synthesized for comparative purposes.It was shown that the use of stannic compounds as catalysts for xerogels with 3-mercaptopropyl groups resulted in a product which possessed a non-porous structure, while the use of fluoride ions allowed the synthesis of a sample with a porous structure (S sp = 216 m 2 /g, V s = 0.152 cm 3 /g, d = 3.5 nm). Xerogels with a bifunctional surface layer possess a bimodal structure. Infrared, Raman and multinuclear solid-state NMR ( 1 H,Si) spectroscopy data showed: (i) the absence of deprotonation for the 3-mercaptopropyl groups in the bifunctional surface layer of the xerogels; and (ii) that 3-aminopropyl groups form hydrogen bonds in these surface layers.The type of hydrogen bond formed depends on the ratio of the amount of water to the amount of 3-aminopropyl groups in the surface layer. When this ratio is about 1:1, the amino group forms a hydrogen bond with the silanol group associated with the water molecule. Re-organization of the surface layer is observed when the amount of water decreases, the amino groups forming hydrogen bonds between themselves. Hence, the system of hydrogen bonds in the surface layer of such xerogels depends primarily on the drying regime employed for the samples.

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“…The concentration variation of such oligomeric species with an increase in C(i) affects strongly the equilibrium states (2 ), (3 ), (4 ), (5 ) and (6 ), changing further the concentrations of these oligomeric species.…”

Section: (A)mentioning

confidence: 98%

“…In particular, the nature of the self-assembly of SCAs in solution [5] is expected to affect strongly the structure of related intermediates or precursors. Indeed, there exists a relationship between the optimum concentration of SCA for enhancement of the interfacial strength and subsequent polymerization [4].…”

Section: Introductionmentioning

confidence: 99%

“…Polymerization processes of alkoxide or alkylalkoxide silanecoupling agents (SCA) have been studied extensively for applications in industry [1][2][3][4][5], especially for chemical modification of surfaces of inorganic materials to enhance their mechanical properties. It is well known that solution processing of polymerization reactions involves various intermediates or precursors, and that types and distributions of such species depend strongly on reaction conditions.…”

Section: Introductionmentioning

confidence: 99%

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Concentration-resolved 2D correlation gel permeation chromatography study of aggregate–aggregate interactions in the polymerization products of triethoxysilyl-terminated polystyrene silane-coupling agent

Suzuki

Oku

Izawa

et al. 2008

Journal of Colloid and Interface Science

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13C- and 1H-NMR and FTIR spectroscopic evidence for aggregate formation of organosilanes in toluene

Cited by 18 publications

References 10 publications

Surface chemistry of the iron tetraazamacrocycle on the aminopropyl‐modified surface of oxidized n‐Si(100) by AFM and XPS

Surface chemistry of the iron tetraazamacrocycle on the aminopropyl‐modified surface of oxidized n‐Si(100) by AFM and XPS

Structural Features of Surface Layers of Bifunctional Polysiloxane Xerogels Containing 3-Aminopropyl Groups and 3-Mercaptopropyl Groups

Concentration-resolved 2D correlation gel permeation chromatography study of aggregate–aggregate interactions in the polymerization products of triethoxysilyl-terminated polystyrene silane-coupling agent

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