4,15-Dimethyl-7,12-diazo-niatri-cyclo-[10.4.0.02,7]hexa-deca-1(12),2,4,6,13,15-hexa-ene dibromide monohydrate

Edward J Behrman; Alexandar L Hansen; Chunhua Yuan; Sean Parkin

doi:10.1107/S2056989020011147

4,15-Dimethyl-7,12-diazo-niatri-cyclo-[10.4.0.0^2,7]hexa-deca-1(12),2,4,6,13,15-hexa-ene dibromide monohydrate

Acta Crystallogr E Crystallogr Commun. 2020 Aug 18;76(Pt 9):1467-1471. doi: 10.1107/S2056989020011147. eCollection 2020 Sep 1.

Authors

Edward J Behrman¹, Alexandar L Hansen², Chunhua Yuan², Sean Parkin³

Affiliations

¹ Department of Chemistry & Biochemistry, The Ohio State University, 484 W. 12th Avenue, Columbus, Ohio, 43210, USA.
² Campus Chemical Instrument Center, The Ohio State University, 496 W. 12th Avenue, Columbus, Ohio, 43210, USA.
³ Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, Kentucky, 40506, USA.

Abstract

The title compound, C₁₆H₂₀N₂ ²⁺·2Br^-·H₂O (1) is a member of the class of compounds called viologens. Viologens are quaternary salts of di-pyridyls and are especially useful as redox indicators as a result of their large negative one-electron reduction potentials. Compound 1 consists of a dication composed of a pair of 4-methyl-pyridine rings mutually joined at the 2-position, with a dihedral angle between the pyridine rings of 62.35 (4)°. In addition, the rings are tethered via the pyridine nitro-gen atoms by a tetra-methyl-ene bridge. Charge balance is provided by a pair of bromide anions, which are hydrogen bonded to a single water mol-ecule [D _O⋯Br = 3.3670 (15) and 3.3856 (15) Å]. The crystal structure of 1, details of an improved synthesis, and a full analysis of its NMR spectra are presented.

Keywords: atropisomer; crystal structure; synthesis; viologen.

Grants and funding

This work was funded by NSF grant CHE1625732 to Sean Parkin.