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Environmentally friendly flame retardants. A detailed solid‐state NMR study of melamine orthophosphate
Author(s) -
Brinkmann Andreas,
Litvinov Victor M.,
Kentgens Arno P. M.
Publication year - 2007
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2159
Subject(s) - chemistry , heteronuclear molecule , solid state nuclear magnetic resonance , melamine , chemical shift , magic angle spinning , proton nmr , nuclear magnetic resonance spectroscopy , protonation , hydrogen bond , nmr spectra database , crystallography , computational chemistry , molecule , nuclear magnetic resonance , spectral line , stereochemistry , organic chemistry , physics , ion , astronomy
Abstract We used solid‐state NMR spectroscopy to gain detailed information about the proton positions, proximities and the hydrogen‐bonding network in the environmentally friendly flame retardant melamine orthophosphate (MP). High‐resolution proton one‐ and two‐dimensional solid‐state NMR spectra were obtained at high external magnetic field in combination with fast magic angle spinning of the sample. Furthermore, we recorded homo‐ and heteronuclear correlation spectra of types 15 N 15 N, 1 H 13 C, 1 H 15 N and 1 H 31 P. In addition, we determined the geometry of the NH and NH 2 groups in MP by 15 N 1 H heteronuclear recoupling experiments. We were able to completely assign the different isotropic chemical shifts in MP. Furthermore, we could identify the protonation of the melamine and orthophosphate moieties. The experimental results are discussed in connection with the structural model obtained by powder X‐ray diffraction together with a combined molecular modeling‐Rietveld refinement approach (De Ridder et al . Helv. Chim. Acta 2004; 87 : 1894). We show that the geometry of the NH 2 groups can only be successfully estimated by solid‐state NMR. Copyright © 2007 John Wiley & Sons, Ltd.