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Single‐crystal X‐ray diffraction and NMR crystallography of a 1:1 cocrystal of dithianon and pyrimethanil
Author(s) -
Pöppler Ann-Christin,
Corlett Emily K.,
Pearce Harriet,
Seymour Mark P.,
Reid Matthew,
Montgomery Mark G.,
Brown Steven P.
Publication year - 2017
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229617000870
Subject(s) - chemistry , chemical shift , crystallography , cocrystal , single crystal , intermolecular force , crystal structure , molecule , magic angle spinning , nmr spectra database , carbon 13 nmr , pyrimethanil , carbon 13 nmr satellite , crystal (programming language) , hydrogen bond , nuclear magnetic resonance spectroscopy , spectral line , fluorine 19 nmr , stereochemistry , organic chemistry , physics , programming language , astronomy , pesticide , agronomy , biology , computer science
A single‐crystal X‐ray diffraction structure of a 1:1 cocrystal of two fungicides, namely dithianon (DI) and pyrimethanil (PM), is reported [systematic name: 5,10‐dioxo‐5 H ,10 H ‐naphtho[2,3‐ b ][1,4]dithiine‐2,3‐dicarbonitrile–4,6‐dimethyl‐ N ‐phenylpyrimidin‐2‐amine (1/1), C 14 H 4 N 2 O 2 S 2 ·C 12 H 13 N 2 ]. Following an NMR crystallography approach, experimental solid‐state magic angle spinning (MAS) NMR spectra are presented together with GIPAW (gauge‐including projector augmented wave) calculations of NMR chemical shieldings. Specifically, experimental 1 H and 13 C chemical shifts are determined from two‐dimensional 1 H– 13 C MAS NMR correlation spectra recorded with short and longer contact times so as to probe one‐bond C—H connectivities and longer‐range C…H proximities, whereas H…H proximities are identified in a 1 H double‐quantum (DQ) MAS NMR spectrum. The performing of separate GIPAW calculations for the full periodic crystal structure and for isolated molecules allows the determination of the change in chemical shift upon going from an isolated molecule to the full crystal structure. For the 1 H NMR chemical shifts, changes of 3.6 and 2.0 ppm correspond to intermolecular N—H…O and C—H…O hydrogen bonding, while changes of −2.7 and −1.5 ppm are due to ring current effects associated with C—H…π interactions. Even though there is a close intermolecular S…O distance of 3.10 Å, it is of note that the molecule‐to‐crystal chemical shifts for the involved sulfur or oxygen nuclei are small.