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A Combined 25 Mg Solid‐State NMR and Ab Initio DFT Approach to Probe the Local Structural Differences in Magnesium Acetate Phases Mg(CH 3 COO) 2 ⋅ nH 2 O (n=0, 1, 4)
Author(s) -
Seymour Valerie R.,
Day Stephen P.,
Scholz Gudrun,
Scheurell Kerstin,
Iuga Dinu,
Griffin John M.,
Kemnitz Erhard,
Hanna John V.,
Smith Mark E.
Publication year - 2018
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201800317
Subject(s) - chemistry , magnesium , crystallography , magic angle spinning , magnesium acetate , solid state nuclear magnetic resonance , crystal structure , nuclear magnetic resonance spectroscopy , density functional theory , coordination complex , nuclear magnetic resonance crystallography , ab initio , carbon 13 nmr satellite , nmr spectra database , computational chemistry , stereochemistry , fluorine 19 nmr , nuclear magnetic resonance , organic chemistry , spectral line , physics , astronomy , metal
Multinuclear ( 1 H, 13 C, 25 Mg) solid‐state NMR data is reported for a series of magnesium acetate phases Mg(CH 3 COO) 2 ⋅ nH 2 O (n=0 (two polymorphs), 1, 4). The central focus here is 25 Mg as this set of compounds provides an expanded range of local magnesium coordinations compared to what has previously been reported in the literature using NMR. These four compounds provide 10 distinct magnesium sites with varying NMR interaction parameters. One of the anhydrous crystal structures (α) has an MgO 7 site which is reported, to the best of our knowledge, for the first time. For those phases with a single crystal structure, a combination of magic angle spinning (MAS) NMR at high magnetic field (20 T) and first principles density functional theory (DFT) calculations demonstrates the value of including 25 Mg in NMR crystallography approaches. For the second anhydrate phase (β), where no single crystal structure exists, the multinuclear NMR data clearly show the multiplicity of sites for the different elements, with 25 Mg satellite transition (ST) MAS NMR revealing four inequivalent magnesium environments, which is new information constraining future refinement of the structure. This study highlights the sensitivity of 25 Mg NMR to the local environment, an observation important for several sub‐disciplines of chemistry where the structural chemistry of magnesium is likely to be crucial.