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N ‐Tosyl‐ l ‐proline benzene hemisolvate: a rare example of a hydrogen‐bonded carboxylic acid dimer with symmetrically disordered H atoms
Author(s) -
Wojnarska Joanna,
Ostrowska Katarzyna,
Gryl Marlena,
Stadnicka Katarzyna Marta
Publication year - 2019
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/s2053229619010829
Subject(s) - hydrogen bond , dimer , chemistry , carboxylic acid , molecule , crystallography , acceptor , crystal structure , tosyl , crystal engineering , benzene , non covalent interactions , stereochemistry , polymer chemistry , organic chemistry , physics , condensed matter physics
The carboxylic acid group is an example of a functional group which possess a good hydrogen‐bond donor (–OH) and acceptor (C=O). For this reason, carboxylic acids have a tendency to self‐assembly by the formation of hydrogen bonds between the donor and acceptor sites. We present here the crystal structure of N ‐tosyl‐ l ‐proline (TPOH) benzene hemisolvate {systematic name: (2 S )‐1‐[(4‐methylbenzene)sulfonyl]pyrrolidine‐2‐carboxylic acid benzene hemisolvate}, C 12 H 15 NO 4 S·0.5C 6 H 6 , (I), in which a cyclic R 2 2 (8) hydrogen‐bonded carboxylic acid dimer with a strong O—(H)…(H)—O hydrogen bond is observed. The compound was characterized by single‐crystal X‐ray diffraction and NMR spectroscopy, and crystallizes in the space group I 2 with half a benzene molecule and one TPOH molecule in the asymmetric unit. The H atom of the carboxyl OH group is disordered over a twofold axis. An analysis of the intermolecular interactions using the noncovalent interaction (NCI) index showed that the TPOH molecules form dimers due to the strong O—(H)…(H)—O hydrogen bond, while the packing of the benzene solvent molecules is governed by weak dispersive interactions. A search of the Cambridge Structural Database revealed that the disordered dimeric motif observed in (I) was found previously only in six crystal structures.