1,3-Dimesitylimidazolidinium tetra­chloridogold(III) dichloro­methane solvate

Tesfamariam K Hagos; Stefan D Nogai; Liliana Dobrzańska; Stephanie Cronje

doi:10.1107/S1600536808031115

. 2008 Oct 4;64(Pt 11):m1357. doi: 10.1107/S1600536808031115

1,3-Dimesitylimidazolidinium tetrachloridogold(III) dichloromethane solvate

Tesfamariam K Hagos ^a, Stefan D Nogai ^a, Liliana Dobrzańska ^a,^*, Stephanie Cronje ^a

PMCID: PMC2959617 PMID: 21580818

Abstract

The title ionic compound, (C₂₁H₂₇N₂)[AuCl₄]·CH₂Cl₂, was obtained from the reaction of 1,3-dimesitylimidazolidinium chloride with t-BuOK and a solution of AuCl₃ in tetrahydrofuran. In the crystal structure, numerous weak C—H⋯Cl hydrogen bonds form double layers parallel to (100), which are further stabilized by π–π interactions between mesitylene rings [centroid–centroid distance = 4.308 (4) Å], resulting in the formation of a three-dimensional supramolecular assembly.

Related literature

For related literature, see: Arduengo et al. (1995 ▶); da Costa et al. (2007 ▶); Adé et al. (2004 ▶); Asaji et al. (2004 ▶); Makotchenko et al. (2006 ▶); Brammer et al. (2001 ▶).

Experimental

Crystal data

(C₂₁H₂₇N₂)[AuCl₄]·CH₂Cl₂
M _r = 731.14
Monoclinic,
a = 19.590 (3) Å
b = 8.9986 (13) Å
c = 15.306 (2) Å
β = 96.601 (2)°
V = 2680.4 (7) Å³
Z = 4
Mo Kα radiation
μ = 6.10 mm⁻¹
T = 100 (2) K
0.30 × 0.25 × 0.10 mm

Data collection

Bruker APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1997 ▶) T _min = 0.146, T _max = 0.546
15546 measured reflections
6083 independent reflections
4516 reflections with I > 2σ(I)
R _int = 0.094

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.086
S = 0.91
6083 reflections
286 parameters
H-atom parameters constrained
Δρ_max = 2.12 e Å⁻³
Δρ_min = −2.24 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2002 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: X-SEED.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808031115/hk2528sup1.cif

e-64-m1357-sup1.cif^{(23.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808031115/hk2528Isup2.hkl

e-64-m1357-Isup2.hkl^{(297.8KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °) (with cut-off parameters as in Brammer et al., 2001 ▶).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9⋯Cl1ⁱ	0.95	2.78	3.706 (6)	164
C12—H12C⋯Cl4ⁱⁱ	0.98	2.87	3.724 (6)	147
C15—H15⋯Cl3ⁱⁱ	0.95	2.87	3.740 (7)	152
C15—H15⋯Cl4ⁱⁱ	0.95	2.88	3.368 (6)	113
C17—H17A⋯Cl4	0.99	3.05	3.794 (6)	133
C17—H17B⋯Cl2ⁱⁱⁱ	0.99	2.95	3.736 (6)	137
C17—H17B⋯Cl3ⁱⁱⁱ	0.99	2.96	3.882 (6)	155
C18—H18B⋯Cl1	0.99	2.78	3.511 (6)	131
C25—H25A⋯Cl4ⁱⁱ	0.98	2.89	3.832 (6)	162
C25—H25B⋯Cl29^iv	0.98	2.88	3.742 (7)	148
C25—H25C⋯Cl2ⁱⁱⁱ	0.98	2.97	3.901 (6)	160
C25—H25C⋯Cl3ⁱⁱⁱ	0.98	3.03	3.691 (6)	126
C26—H26B⋯Cl4	0.98	2.90	3.829 (7)	158
C27—H27C⋯Cl30^v	0.98	3.04	3.838 (8)	140
C28—H28A⋯Cl3	0.99	2.63	3.486 (7)	145

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

Acknowledgments

The authors thank the National Research Foundation of South Africa and the University of Stellenbosch for financial support.

supplementary crystallographic information

Comment

During the course of ongoing studies on imine compounds of gold(III), we have isolated the title ionic compound, (I). The asymmetric unit (Fig. 1) consists of 1,3-dimesitylimidazolidinium cation, tetrachloro-gold(III) anion, and a dichloromethane molecule. To the best of our knowledge, there have been only two reports on crystal structures containing the title carbenium ion, presenting the structure of the 1,3-dimesitylimidazolidinium chloride acetonitrile solvate, (II), (Arduengo et al., 1995) and the imidazolidinium salt of a ruthenium(III) complex, (III) (da Costa et al., 2007), respectively. The structural parameters associated with the carbenium ion are similar to the reported ones. The only difference is the orientation of one of the mesitylene rings (C19-C24), which is almost perpendicular with respect to the plane of the imidazolidinium ring. The dihedral angle between those two planes is 89.5 (3)°, whereas in previous reports both the mesitylene rings were more or less twisted with respect to the plane of the imidazolidinium ring [66.0 (3)° and 75.1 (3)°] for (II) and 82.0 (3)° for (III). This corresponds with the orientation of the other mesitylene ring (C5-C10) [72.1 (3)°] described here.

The anionic part displays a typical square-planar geometry around Au and the Au-Cl distances compare well with previously reported values (Adé et al., 2004; Asaji et al., 2004; Makotchenko et al., 2006). All Cl atoms participate in the formation of weak C-H···Cl hydrogen bonds (Table 1) forming double layers in the bc plane [individual layers are linked by C27-H27C···Cl30 bonds with C···Cl distance of 3.838 (8) Å] which are further extended in the third dimension by face-to-face π-π interactions between mesitylene rings (C5-C10) of neighbouring double layers [symmetry code: 2 - x, -y, 1 - z] with centroid-centroid distance of 4.308 (4) Å (Fig. 2).

Experimental

For the preparation of the title compound, 1,3-dimesitylimidazolidinium chloride (0.04 g, 1.2 mmol) in THF (20 ml) was treated with t-BuOK (0.13 g, 1.2 mmol) at room temperature, and then filtered through Celite into a solution of AuCl₃ (0.35 g, 1.2 mmol) in THF (20 ml). The solvent was removed under reduced pressure. Orange crystals suitable for single crystal X-ray analysis were obtained from a dichloromethane solution layered with hexane at 253 K.