(IUCr) Crystallography Journals Online

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Acta Cryst. (2004). E60, m1836-m1840 [ doi:10.1107/S1600536804028259 ]

The sterically crowded four-coordinate copper(I) complex rac-bis[2,2'-bis(1-ethyl-1H-benzimidazol-2-yl)biphenyl]copper(I) trifluoromethanesulfonate toluene solvate dihydrate

R. T. Stibrany, H. J. Schugar and J. A. Potenza

Abstract: The title salt, rac-[Cu(C₃₀H₂₆N₄)₂](CF₃SO₃)·C₇H₈·2H₂O, contains Cu(L1)₂⁺ cations, where L1 is 2,2'-bis(1-ethylbenzimidazol-2-yl)biphenyl, separated by trifluoromethanesulfonate anions, toluene solvent molecules and two water molecules of hydration, only one of which could be defined crystallographically. Chemical and crystallographic evidence are consistent with a second, highly disordered water molecule in the asymmetric unit located in voids of 111 Å³. The ligands L1 form two nine-membered chelate rings with the Cu^I ion, resulting in a Cu[N(imine)]₄ coordination geometry which is best described as distorted 222 (D₂). Cu-N bond distances in the coordination sphere are long compared with those in other four-coordinate copper(I) structures containing benzimidazole ligands, possibly owing to the steric bulk associated with the ligands L1. Within each cation, the eight ring systems, consisting of four benzimidazole and four benzene fragments, are linked together by weak C-H [pi] and C-HN interactions, suggesting that the cations are relatively tightly constrained sterically. The structure, when viewed along the b direction, may be described as a criss-crossed array of alternating cation/toluene and anion/water columns along the b direction arranged parallel to the (102) and (10 $\overline 2$ ) planes.

Online 13 November 2004