Crystal structures of [μ2-(Ra , Sa ,3a R,7a R)-1,3-bis-(2,7-di-cyclo-hexyl-naphthalen-1-yl)octa-hydro-1 H-benzo[ d]imidazolidin-2-yl-idene]chlorido-(η4-1,5-cyclo-octa-diene)iridium di-chloro-methane monosolvate and [μ2-(Sa , Sa ,3a R,7a R)-1,3-bis-(2,7-di-cyclo-hexyl-naphthalen-1-yl)octa-hydro-1 H-benzo[ d]imidazolidin-2-yl-idene]chlorido-(η4-1,5-cyclo-octa-diene)iridium

Stephen A Moggach; Brian W Skelton; Daven J Foster

doi:10.1107/S2056989020011603

Crystal structures of [μ₂-(R_a , S_a ,3a R,7a R)-1,3-bis-(2,7-di-cyclo-hexyl-naphthalen-1-yl)octa-hydro-1 H-benzo[ d]imidazolidin-2-yl-idene]chlorido-(η⁴-1,5-cyclo-octa-diene)iridium di-chloro-methane monosolvate and [μ₂-(S_a , S_a ,3a R,7a R)-1,3-bis-(2,7-di-cyclo-hexyl-naphthalen-1-yl)octa-hydro-1 H-benzo[ d]imidazolidin-2-yl-idene]chlorido-(η⁴-1,5-cyclo-octa-diene)iridium

Acta Crystallogr E Crystallogr Commun. 2020 Sep 4;76(Pt 10):1543-1547. doi: 10.1107/S2056989020011603. eCollection 2020 Oct 1.

Authors

Stephen A Moggach¹, Brian W Skelton¹, Daven J Foster²

Affiliations

¹ Centre for Microscopy, Characterisation and Analysis, University of Western Australia, 35 Stirling Highway, 6009 Perth, Western Australia, Australia.
² Department of Chemistry, School of Molecular Sciences, University of Western Australia, M310, 35 Stirling Highway, 6009 Perth, Western Australia, Australia.

Abstract

The title compounds, [Ir(C₅₁H₆₄N₂)Cl(C₈H₁₂)]·CH₂Cl₂, (I), and [Ir(C₅₁H₆₄N₂)Cl(C₈H₁₂)], (II), represent the first two examples of hexa-hydro-benzo-imidazole-based N-heterocyclic carbene (NHC) iridium complexes. The diastereomeric complexes differing only in their axial chirality, which could be separated via column chromatography, show noticeable differences in their ¹H NMR spectra. Compound (I) crystallizes in the monoclinic system (P2₁) with two independent complexes and two half-occupied di-chloro-methane mol-ecules in the asymmetric unit, while compound (II) crystallizes in the ortho-rhom-bic system (P2₁2₁2₁) with one complex in the asymmetric unit. The fused five-membered N-heterocycles of NHCs show unusually high backbone torsion angles of -34.1 (5) and -30.9 (5)° for (I) and -31.5 (7)° for (II), but the Ir-C_carbene bond lengths of 2.046 (6) and 2.021 (6) Å for (I) and 2.045 (8) Å for (II) present typical NHC-Ir bond lengths. The solvent mol-ecule in the crystal of (I) was found to be highly disordered and its contribution to the scattering was masked using the solvent-masking routine smtbx.mask in OLEX2 [Dolomanov et al. (2009 ▸). J. Appl. Cryst. 42, 339-341]. The solvent contribution is not included in the reported chemical formula and other crystal data.

Keywords: N-heterocyclic carbene; crystal structure; cyclooctadiene; iridium; naphthyl.

Grants and funding

This work was funded by The University of Western Australia grant .