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Lead nitrate is an inorganic salt, commonly used for the accurate temperature determination in the solid state NMR spectroscopy, due to the strong temperature dependence of the 207Pb chemical shift. As the reason for this phenomenon remained unknown, the main purpose of this study was to explain this temperature dependence at the molecular level. To achieve this, combined CASTEP geometry optimization, quantum molecular dynamics at chosen temperatures and GIPAW NMR computations were performed. Due to the previous literature reports on inaccuracy in the calculation of 207Pb NMR parameters using GIPAW, a large emphasis was put on the optimization of computational method. The application of quantum molecular dynamics provided the simulation of the temperature‐dependent vibrational motions and enabled to accurately compute the changes in the value of Pb δiso resulting from them. © 2018 Wiley Periodicals, Inc. This study aims to explain, at the molecular level, the experimentally observed temperature dependence of 207Pb isotropic chemical shift value in the solid state NMR spectra of lead nitrate. For this purpose combined CASTEP geometry optimization, quantum molecular dynamics at chosen temperatures and GIPAW calculations of NMR parameters were performed. The influence of temperature‐depending vibrational motions on the NMR parameters was precisely reflected in the calculations results. [ABSTRACT FROM AUTHOR]

Abstract: Single-crystal and powder X-ray diffraction, 13C CP/MAS NMR, and DFT-GIAO calculations of shielding constants were performed for methyl 3,4,6-tri-O-acetyl-2-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-α-d-glucopyranoside (1) and methyl 2,4,6-tri-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-α-d-glucopyranoside (2). 1 crystallizes with three molecules whereas 2 with two molecules in an independent part of the unit cell. The macroscopic sample of 1 consists of one polymorph, while for 2 two or three polymorphs were detected. The existence of different numbers of the molecules in the asymmetric units as well as different numbers of polymorphs of 1 and 2 was verified by solid-state NMR spectroscopy. [Copyright &y& Elsevier]