Structural parameters of dimethyl sulfoxide, DMSO, at 100 K, based on a redetermination by use of high-quality single-crystal X-ray data

• Main Author: Hans Reuter
• Format: Article
• Language: English
• Published: International Union of Crystallography 2017-10-01
• Series: Acta Crystallographica Section E: Crystallographic Communications
• Subjects: crystal structure; dimethyl sulfoxide; van der Waals interaction; geometric parameters; crystal packing
• Online Access: http://scripts.iucr.org/cgi-bin/paper?S2056989017012464

The title compound, C2H6OS, is a high melting, polar and aprotic solvent widely used in organic and inorganic chemistry. It serves as a H-atom acceptor in hydrogen bonding and is used as an ambidentate ligand in coordination chemistry. The evaluation of the influence of intermolecular interactions on the internal structural parameters of the chemically bonded DMSO molecules affords precise structural data of the free molecule as a point of reference. So far, valid data have been obtained only by use of neutron powder diffraction [Ibberson (2005). Acta Cryst. C61, o571–o573]. In the present redetermination, structural data have been obtained from a single-crystal X-ray diffraction experiment at 100 K, revealing a better comparison with DMSO molecules in other crystal structures. In the solid state, the pyramidal molecule exhibits a nearly perfect Cs symmetry [including H atoms, which are eclipsed with respect to the C...C axis], with a C—S—C bond angle of 97.73 (7)° and an S—O bond length of 1.5040 (10) Å, corresponding very well with an S=O double bond, and with almost equal S—C bond lengths [mean value = 1.783 (4) Å] and O—S—C bond angles [mean value = 106.57 (4)°]. The crystal packing is influenced by C—H...O interactions (2.42–2.47 Å) between all three H atoms of only one methyl group with the O atoms of three neighbouring DMSO molecules. The interactions of the O atom with H atoms (or Lewis acids, or hydrogen-donor groups) of adjacent molecules in relation to the orientation of the complete DMSO molecule are described in terms of the angle ω and the distance dnorm; ω is the angle between the pseudo-mirror plane of the molecule and the plane defined through the S=O bond and the interacting atom, and dnorm is the distance of the interacting atom from the plane perpendicular to the S=O bond.