Structures and Dynamics of Secondary and Tertiary Alkylphosphine Oxides Adsorbed on Silica

Kharel, Sugam; Cluff, Kyle J.; Bhuvanesh, Nattamai; Gladysz, J. A.; Blümel, Janet

doi:10.1002/asia.201900632

Cited by 24 publications

(25 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The spherically rather symmetric phosphonium salts, for example, have a small 31 P CSA in the solid state, 21f,g while polycrystalline phosphine oxides display a large CSA. 24,25 The same accounts for phosphines versus their metal complexes. 21 A large CSA manifests in solid-state NMR spectra in the form of multiple sets of rotational sidebands in addition to the isotropic line when samples are rotated.…”

Section: ■ Introductionmentioning

confidence: 99%

“…We reported recently that species such as phosphine oxides 26 can be adsorbed on diverse surfaces by dry grinding, and we could demonstrate that they are mobile on silica surfaces. 24,25 Regarding the adsorption of phosphine oxides on silica, the interactions with the surface are rather well-defined. The oxygen of the PO functionality forms hydrogen bonds with surface silanol groups.…”

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ferrocene Adsorbed on Silica and Activated Carbon Surfaces: A Solid-State NMR Study of Molecular Dynamics and Surface Interactions

et al. 2020

Self Cite

View full text Add to dashboard Cite

Ferrocene has been adsorbed on the surface of silica and activated carbon within the pores by dry grinding in the absence of a solvent at room temperature. While the dry adsorption and translational mobility of ferrocene within the pores are already established on the centimeter scale, there is little systematic understanding of the surface site-to-site motions of the ferrocene molecules and their orientation with respect to the surface. In this paper, silica and activated carbon, both widely applied in academia and industry as adsorbents, are used as support materials. Using variable-temperature 13C and 2H solid-state NMR and T 1 relaxation time measurements, the dynamics of ferrocene on the surfaces of silica and activated carbon within the pores has been quantitatively characterized on the molecular scale. The obtained data indicate that ferrocene molecules show a liquid-like behavior on the surface. Fast exchange between isotropically moving molecules and surface-attached molecular states of ferrocene has been found in samples with submonolayer surface coverages. The surface-attached molecular states have been characterized by the free energies ΔG ⧧ of 6.1 kcal/mol for silica and ΔG ⧧ of 6.2 kcal/mol for activated carbon at 223 and 263 K, respectively. The horizontally oriented ferrocene molecules are the most thermodynamically stable states on the surfaces of both materials. These molecules exhibit fast C5 rotation of the Cp rings, as established by low-temperature 13C and 2H NMR. The interactions of ferrocene with the pore surfaces have been characterized by adsorption enthalpies measured as −8.4 to −7.0 kcal/mol and −6.7 kcal/mol for activated carbon and silica, respectively. It has been suggested that the ferrocene–surface interactions for both support materials have a polar character.

show abstract

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Ferrocene Adsorbed on Silica and Activated Carbon Surfaces: A Solid-State NMR Study of Molecular Dynamics and Surface Interactions

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…31 P NMR can be routinely used in the evaluation of the structure of organic complexes in solution [90,91] and solids [92][93][94] including organometallic compounds [26,[95][96][97][98]. Molecules containing phosphorus are very convenient NMR probes for studying mobility at interfaces [99][100][101]. For example, 31 P NMR has been used to elucidate thermal and hydration effects on the mobility of compact, branched, and bulky pharmaceutical molecules loaded in submonolayer amounts onto mesoporous silica [102].…”

Section: P Nmrmentioning

confidence: 99%

Solid State NMR for Nonexperts: An Overview of Simple but General Practical Methods

Shenderovich

Limbach

2021

Solids

View full text Add to dashboard Cite

There are varieties of methods available for the exploration of solids using nuclear magnetic resonance (NMR) spectroscopy. Some of these methods are quite sophisticated, others require specialized equipment. This review is addressed to those for whom NMR is not the main research method. It discusses simple methods that can be applied to solids with little or no adaptation to a specific system. Despite their technical simplicity and ease of use, these methods are powerful analytical tools that provide unique insights into the structure, dynamics, and noncovalent interactions in homo- and heterogeneous systems. Particular attention is paid to the characterization of porous materials and solids containing phosphorus. 31P NMR of organometallic compounds has been used as an example of how theoretical calculations can help in deeper analysis of experimental data.

show abstract

“…Phosphorous is involved in a large number of chemical processes [8] and systems. [9] The conformation [10] of phosphorous containing molecules, noncovalent interactions [11] and dynamic processes [12] involved in, can be elucidated by NMR. Quantum mechanical simulations of 31 P NMR quantities in such systems do not necessarily require specific soft-or hardware; this opening up new possibilities for advanced studies.…”

Section: Introductionmentioning

confidence: 99%

Experimentally Established Benchmark Calculations of ³¹P NMR Quantities

Shenderovich

2020

Chemistry Methods

View full text Add to dashboard Cite

The accuracy of different density function theory functionals and the MP2 approximation in 31P NMR calculations has been evaluated for ten phosphorous containing molecules in which the phosphorous atoms are not involved in intermolecular interactions. The obtained absolute chemical shielding tensors are compared to experimental ones. The dependence of the numerical values on the size of basis sets has been inspected from the 6‐311G(2d,p) to the pcSseg‐3 basis sets. General recommendations on the most reliable functionals and the smallest possible size of a basis set have been reported. For example, the use of the M06 L functional should be avoided. For five polycrystalline samples, the conformation of molecules has been identified with a high precision. These structures have been used to determine the reference values of the absolute chemical shielding for the TPSSh, B3LYP, and ωB97XD functionals and different basis sets. As reported in the supporting information, these structures can be used to determine the reference value of the absolute chemical shielding for any approximation of interest.

show abstract

Structures and Dynamics of Secondary and Tertiary Alkylphosphine Oxides Adsorbed on Silica

Cited by 24 publications

References 71 publications

Ferrocene Adsorbed on Silica and Activated Carbon Surfaces: A Solid-State NMR Study of Molecular Dynamics and Surface Interactions

Ferrocene Adsorbed on Silica and Activated Carbon Surfaces: A Solid-State NMR Study of Molecular Dynamics and Surface Interactions

Solid State NMR for Nonexperts: An Overview of Simple but General Practical Methods

Experimentally Established Benchmark Calculations of ³¹P NMR Quantities

Contact Info

Product

Resources

About

Structures and Dynamics of Secondary and Tertiary Alkylphosphine Oxides Adsorbed on Silica

Cited by 24 publications

References 71 publications

Ferrocene Adsorbed on Silica and Activated Carbon Surfaces: A Solid-State NMR Study of Molecular Dynamics and Surface Interactions

Ferrocene Adsorbed on Silica and Activated Carbon Surfaces: A Solid-State NMR Study of Molecular Dynamics and Surface Interactions

Solid State NMR for Nonexperts: An Overview of Simple but General Practical Methods

Experimentally Established Benchmark Calculations of 31P NMR Quantities

Contact Info

Product

Resources

About

Experimentally Established Benchmark Calculations of ³¹P NMR Quantities