Solid-state NMR Studies of Supported Transition Metal Catalysts and Nanoparticles

Gutmann, Torsten; Buntkowsky, Gerd

doi:10.1007/978-3-319-28275-6_39-1

Cited by 9 publications

(7 citation statements)

References 123 publications

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“…However, these techniques suffer from resolution, which makes their interpretation challenging, especially when complex hybrid material containing inorganic and organic components are involved. As an alternative to solve this structural puzzle, solid-state NMR has been evaluated to characterize inorganic-organic hybrid materials, and the interactions of organic components with inorganic ones [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. This technique has the advantage that the nuclei of the inorganic component, i.e., 29 Si, and the nuclei of the organic component, i.e., 13 C, have specific chemical shift ranges that allow a precise analysis of their chemical environment and thus the clear identification of functional groups and their connectivity.…”

Section: Resultsmentioning

confidence: 99%

Free-Standing and Self-Crosslinkable Hybrid Films by Core–Shell Particle Design and Processing

et al. 2017

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The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a core-shell particle architecture. The synthesis of well-designed monodisperse core-shell particles by emulsion polymerization is the basic prerequisite for subsequent particle processing via the melt-shear organization technique. In more detail, the core particles consist of polystyrene (PS) or poly(methyl methacrylate) (PMMA), while the comparably soft particle shell consists of poly(ethyl acrylate) (PEA) and different alkoxysilane-based poly(methacrylate)s. For hybrid film formation and convenient self-cross-linking, different alkyl groups at the siloxane moieties were investigated in detail by solid-state Magic-Angle Spinning Nuclear Magnetic Resonance (MAS, NMR) spectroscopy revealing different crosslinking capabilities, which strongly influence the properties of the core or shell particle films with respect to transparency and iridescent reflection colors. Furthermore, solid-state NMR spectroscopy and investigation of the thermal properties by differential scanning calorimetry (DSC) measurements allow for insights into the cross-linking capabilities prior to and after synthesis, as well as after the thermally and pressure-induced processing steps. Subsequently, free-standing and self-crosslinked particle-based films featuring excellent particle order are obtained by application of the melt-shear organization technique, as shown by microscopy (TEM, SEM).

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Section: Resultsmentioning

confidence: 99%

Free-Standing and Self-Crosslinkable Hybrid Films by Core–Shell Particle Design and Processing

et al. 2017

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“…Solid-state nuclear magnetic resonance (NMR) is a powerful technique that provides such information . However, there are some limitations in terms of low intrinsic sensitivity for biopolymers that have only small surface areas, contain small amounts of surface molecules, or when nuclei such as 15 N have to be detected by solid-state NMR. − To overcome this disadvantage, it is necessary to boost the sensitivity which can be done by a combination of solid-state NMR with dynamic nuclear polarization (solid-state DNP). − This technique uses the polarization of unpaired electrons, which is 3 orders of magnitude higher and transfers it into nuclear polarization. Thus, the sensitivity of solid-state NMR is significantly enhanced as shown recently for a variety of cellulose-based materials. ,− …”

Section: Introductionmentioning

confidence: 99%

Light Amplification Materials Based on Biopolymers Doped with Dye Molecules—Structural Insights from ¹⁵N and ¹³C Solid-State Dynamic Nuclear Polarization

et al. 2021

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13 C and 15 N solid-state nuclear magnetic resonance (NMR) combined with dynamic nuclear polarization (DNP) is used to investigate the structure of dye-doped biopolymer-based materials that can be used in amplified spontaneous emission (ASE) experiments. By comparing calligraphic paper prepared from cellulose and scaffolds prepared from chitosan as substrates, differences in the interactions of the carrier material with the dye molecule Calcofluor White are obtained. These are most probably induced by structural changes of the carrier material due to its interaction with water forming hydrogen bonds. Such structural differences may explain the obtained variation of the emission wavelength of Calcofluor White doped on these substrates in ASE experiments.

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“…Like other homogeneous catalysts, [RhCl(PPh 3 ) 3 ] suffers from challenging product separation, expensive recycling, and probable deactivation during the catalytic reaction. − These issues limit the applications of Wilkinson’s catalyst in reactions to manufacture fine chemicals and pharmaceuticals or to produce hyperpolarized agents for PHIP applications. Thus, researchers including some of us attempted to overcome these drawbacks by immobilizing Wilkinson’s catalyst via coordination bonds to the functional groups located on the surface of solid supports (see reviews and and references therein). This immobilization process aimed to produce a separable and recyclable Wilkinson’s type catalyst with efficient hydrogenation activity.…”

Section: Introductionmentioning

confidence: 99%

A Novel Wilkinson’s Type Silica Supported Polymer Catalyst: Insights from Solid-State NMR and Hyperpolarization Techniques

et al. 2021

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The synthesis of a novel immobilized Wilkinson’s catalyst [SiO2∼PvPy-Wilk] is presented. The support material of this catalyst consists of silica particles that are modified with polymer brushes carrying pyridyl moieties that enable the coordination of Wilkinson’s catalyst. The synthesis of this catalyst is monitored by 1D and 2D multinuclear solid-state NMR techniques to confirm the success of the immobilization. The [SiO2∼PvPy-Wilk] catalyst is then tested in the hydrogenation of styrene, and its reusability is inspected showing that significant structural changes after several reaction cycles yield an activation of the catalyst. Finally, the catalyst is tested in PHIP experiments giving rise to about 200-fold enhancement of the signals of the hydrogenation product ethylbenzene.

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Solid-state NMR Studies of Supported Transition Metal Catalysts and Nanoparticles

Cited by 9 publications

References 123 publications

Free-Standing and Self-Crosslinkable Hybrid Films by Core–Shell Particle Design and Processing

Free-Standing and Self-Crosslinkable Hybrid Films by Core–Shell Particle Design and Processing

Light Amplification Materials Based on Biopolymers Doped with Dye Molecules—Structural Insights from ¹⁵N and ¹³C Solid-State Dynamic Nuclear Polarization

A Novel Wilkinson’s Type Silica Supported Polymer Catalyst: Insights from Solid-State NMR and Hyperpolarization Techniques

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Solid-state NMR Studies of Supported Transition Metal Catalysts and Nanoparticles

Cited by 9 publications

References 123 publications

Free-Standing and Self-Crosslinkable Hybrid Films by Core–Shell Particle Design and Processing

Free-Standing and Self-Crosslinkable Hybrid Films by Core–Shell Particle Design and Processing

Light Amplification Materials Based on Biopolymers Doped with Dye Molecules—Structural Insights from 15N and 13C Solid-State Dynamic Nuclear Polarization

A Novel Wilkinson’s Type Silica Supported Polymer Catalyst: Insights from Solid-State NMR and Hyperpolarization Techniques

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Light Amplification Materials Based on Biopolymers Doped with Dye Molecules—Structural Insights from ¹⁵N and ¹³C Solid-State Dynamic Nuclear Polarization