Surface-Selective Solution NMR Studies of Functionalized Zeolite Nanoparticles

Abstract

The surface chemistry of zeolite nanoparticles functionalized with the organosilane aminopropyldimethylmethoxysilane (APDMMS) was selectively probed using solution (1)H NMR spectroscopy. The use of solution NMR spectroscopy results in high-resolution NMR spectra, and the technique is selective for protons on the surface organic functional groups due to their motional averaging in solution. In this study, (1)H solution NMR spectroscopy was used to investigate the interface of the organic functional groups of APDMMS-functionalized silicalite nanoparticles (∼35 nm) in D2O. The pKa for the amine group of APDMMS-functionalized silicalite nanoparticles in D2O was determined using an NMR-pH titration method based on the variation in the proton chemical shift for the alkyl group protons closest to the amine group with pH. The resulting NMR spectra demonstrate the sensitivity of solution NMR spectroscopy to the electronic environment and structure of the surface functional groups.

Surface Modification of a MXene by an Aminosilane Coupling Agent

“…However, the number of peaks is lower than what is expected (Figure 2A). This may be due to overlapping of some peaks with each other, the hydrogen bonding between the species in the system or other solvent effects . Figure 2A shows a sharp peak around 3.3 ppm, which can be attributed to the hydrogens in the methoxy groups (3.3–3.6 ppm) .…”

“…This may be due to overlapping of some peaks with each other, the hydrogen bonding between the species in the system or other solvent effects. [28][29][30][31] Figure 2A shows a sharp peak around 3.3 ppm, which can be attributed to the hydrogens in the methoxy groups (3.3-3.6 ppm). [32] These are the hydrogens that are labeled as type 1 in Figure S2 (Sup porting Information).…”

Proton NMR studies of functionalized nanoparticles in aqueous environments

“…I = 1/2, 3/2, 5/2 ....), and a few have no spin, I = 0 (e.g. 12 C, 16 O, 32 S….). NMR can only be performed on isotopes whose spin nuclear value is non-zero.…”

Synthesis, characterization of mixed- ligand complexes containing 2,2-Bipyridine and 3-aminopropyltriethoxysilane

“…Fig.6 shows general structure for prepared complexes. [23,24] , 7.22 -8.812 ppm belong to protons of bpy [3,25] . [26,27] , 7.245-12.003 ppm belong to protons of bpy [3,25] .…”