Solid-State ¹⁷O NMR Studies of Sulfonate Jump Dynamics in Crystalline Sulfonic Acids: Insights into the Hydrogen Bonding Effect

Abstract

We report variable-temperature (VT) 17O solid-state nuclear magnetic resonance (NMR) spectra for three crystalline sulfonic acids: l-cysteic acid monohydrate (CA), 3-pyridinesulfonic acid (PSA), and p-toluenesulfonic acid monohydrate (TSA). We were able to analyze the experimental VT 17O NMR spectra to obtain the activation barriers for SO3 – jumps in these systems. Using the density functional-based tight-binding (DFTB) method, we performed potential energy surface scans for SO3 – jumps in the crystal lattice of CA, PSA, and TSA, as well as for three related crystalline sulfonic acids (taurine, homotaurine, and 4-aminobutane-1-sulfonic acid) for which relevant 17O solid-state NMR data are available in the literature. The calculated activation barriers are in reasonable agreement with the experimental values. On the basis of the DFTB results, we hypothesized that activation barriers for SO3 – jumps in the crystal lattice depend largely on the hydrogen bonding energy difference between the ground state and the transition state.

Residue-Specific High-Resolution 17O Solid-State Nuclear Magnetic Resonance of Peptides: Multidimensional Indirect 1H Detection and Magic-Angle Spinning

“…However, in the past few years, several approaches have been reported to address these obstacles. First, new methods to 17 O label peptides and carbohydrates using synthetic and acid-catalyzed exchange methods have been reported. − Notably, 17 O labeled amino acids have been selectively incorporated into recombinant proteins making 17 O NMR feasible for biomacromolecules. , Recently, mechanochemistry has also been shown to be a robust and economic method for 17 O enrichment of a variety of compounds. − Second, higher field NMR magnets and instrumentation have also contributed greatly to facilitating 17 O NMR spectroscopy. Magnetic fields up to 35.2 T have provided dramatic enhancements in spectral resolution and sensitivity through reduction of the second-order quadrupolar broadening, as illustrated in spectra of peptides and metal–organic frameworks (MOFs). ,,,, Third, cryogenic magic-angle spinning (MAS) probes and dynamic nuclear polarization have recently been used to yield a multifold increase in much needed spectral sensitivity. ,, Finally, solid-state NMR methods such as multiple-quantum magic-angle spinning (MQMAS) and satellite-transition magic-angle spinning (STMAS) which provide high-resolution isotropic spectra of half-integer quadrupolar nuclei are becoming increasingly popular for 17 O experiments.…”

NaGaPO4F – a KTiOPO4-structured solid sodium-ion conductor

“…, in the absence of atomic motion). 69–77 Taking into account the ω Q (2) RL values for Na1 and Na2 in NaGaPO 4 F and the temperature range of motional changes in the 23 Na NMR spectrum, we can evaluate τ d −1 ∼ 10 3 –10 4 s −1 at T ≈ 300–350 K.…”

“…In particular, the motional changes in the NMR spectrum can be expected at temperatures at which the ion jump frequency, τ d −1 , becomes comparable with the characteristic frequency of the interaction determining the NMR line shape in a "rigid lattice" (i.e., in the absence of atomic motion). [69][70][71][72][73][74][75][76][77] Taking into account the ω Q…”

Cyclopentadienone Iron Complex-Catalyzed Hydrogenation of Ketones: The Influence of the Charge-Tag on Catalytic Performance

“…No change in the chemical shift would in turn suggest that no interaction takes place. Since the sulfonate charge-tagged complex [F e TMS (CO) 3 -SO 3 ]­Na contains no nuclei that can give conclusive information about the tag binding to iron ( 1 H, 13 C, 29 Si, 14 N/ 15 N) or nuclei that are cumbersome to work with − and/or very expensive to enrich − ( 57 Fe, 17 O, 33 S), we decided to prepare an “NMR-tagged” derivative. The next closest analogues to sulfonates are selenonates, which would offer 77 Se NMR (S = 1/2, 7.6% natural abundance) as a diagnostic tool.…”