Single-crystal X-ray diffraction and NMR crystallography of a 1:1 cocrystal of dithianon and pyrimethanil

Abstract

A combined single-crystal X-ray diffraction and NMR crystallography study of a 1:1 cocrystal of two fungicides, namely di­thia­non and pyrimethanil, is presented. Specifically, the role of hydrogen bonding and C—H⋯π and S⋯O inter­molecular inter­actions is qu­anti­tatively investigated.

An XRD and NMR crystallographic investigation of the structure of 2,6-lutidinium hydrogen fumarate

“…Generally, the level of agreement between experiment and calculation was within the established discrepancy of such calculations of 1% of the chemical shift range. 9,27,[68][69][70] The broad peak at 5-9 ppm in the 1 H MAS NMR spectrum (Fig. 3a) is in agreement with GIPAW calculation.…”

“…calculated for individual isolated molecules, as extracted from the geometry optimised crystal structure, can provide additional insight into the crystal packing. 27,28,45,[72][73][74] The difference between the crystal and isolated molecule chemical shifts (Table 3) indicates the presence of intermolecular interactions, with changes of more than 1 ppm being considered significant. Positive values of Δδ Crystal−Molecule are attributed to the presence of hydrogen bonding, while negative values arise due to ring currents from C-H⋯π interactions.…”

“…8 NMR crystallography [15][16][17][18][19] is a growing field in which solidstate NMR, under magic-angle spinning (MAS), and calculations of NMR parameters from first principles using density functional theory (DFT), notably the gauge-including projector-augmented wave (GIPAW) method, are combined. 20,21 It complements other techniques (generally XRD) to either facilitate structure determination, 9,16,[22][23][24] interrogate the nature of both weak and strong intermolecular interactions [25][26][27][28] or investigate the structure of localised disorder within systems. 29 NMR crystallography of organic systems benefits particularly from the intrinsic sensitivity of 1 H chemical shifts to local interactions.…”

5‐amino‐2‐methylpyridinium hydrogen fumarate: An XRD and NMR crystallography analysis

“…Comparing the GIPAW chemical shifts calculated for the entire crystal structure to those calculated for individual isolated molecules, as extracted from the geometryoptimised crystal structure, is useful as significant differences between the two indicate the presence of intermolecular interactions. [34,41,[49][50][51][52]] For 1 H, changes are considered significant for Δδ Cryst-Mol exceeding 1 ppm. The isolated molecule calculations for 52AMP:F identify only the four classical H-bonds (Table 6) that were assumed from proximities and angles within the crystal structure ( Table 2).…”

Recent Advances in Solid-State Nuclear Magnetic Resonance Spectroscopy

“…(10,11) To date, the combination of experimental NMR experiments and DFT calculations has been successfully demonstrated for a wide array of systems, including minerals, ceramics, porous framework materials, pharmaceuticals, co-crystals, layered systems and energy materials. (8,9,19,(75)(76)(77)(78)(79)(80)(81)(82) To successfully calculate or predict NMR parameters, an accurate structural model is an essential pre-requisite. Models can be generated from experiment (typically using diffraction methods) or computationally (by modification of a known structure or via crystal structure prediction (CSP) methods).…”