Crystal structure of bis[1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]silver(I) chloride tetrahydrofuran monosolvate

In the title compound, the silver atom is coordinated by two 1,3-bis(2,6-dimethylphenyl)imidazol-2-ylidene ligands, with the imidazole rings inclined to one another by 46.69 (13)°. In the crystal, molecules are linked by trifurcated C—H⋯(Cl,Cl,Cl) hydrogen bonds, forming two-dimensional networks parallel to (010).

In the title salt, [Ag(C 27 H 36 N 2 ) 2 ]ClÁC 4 H 8 O, the Ag I atom is coordinated by two 1,3-bis(2,6-dimethylphenyl)imidazol-2-ylidene ligands. The imidazole rings are inclined to one another by 46.69 (13) and the benzene rings in each ligand are almost normal to the imdazole ring to which they are attached, with dihedral angles varying from 82.39 (13) to 88.27 (12) . There are C-HÁ Á Á interactions present in the cation, involving the two ligands, and the solvent molecule is linked to the cation via a C-HÁ Á ÁO hydrogen bond. In the crystal, molecules are linked by trifurcated C-HÁ Á Á(Cl,Cl,Cl) hydrogen bonds, forming slabs parallel to (101). One isopropyl group is disordered over two sets of sites with an occupancy ratio of 0.447 (17):0.553 (17) and the THF molecule is disordered over two positions with an occupancy ratio of 0.589 (6):0.411 (6).
A database search (CSD, Version 5.36, November 2014; Groom & Allen, 2014) for [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]silver yielded eight hits with ten fragments. The mean Ag-C bond length in these structures is 2.09 (3) Å . These values agree well with those for the title compound, viz. The molecular structure of the title compound (I), with atom labelling. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen atoms and the minor occupied sites of the disordered isopropyl group and the disordered THF molecule have been omitted for clarity. Table 1 Hydrogen-bond geometry (Å , ).

Figure 2
The crystal packing of the title compound (I), viewed along the b axis. The C-HÁ Á ÁCl and C-HÁ Á ÁO hydrogen bonds are shown as dashed lines (see Table 1 for details). Disordered atoms and H atoms not involved in hydrogen bonding have been omitted for clarity (Ag silver ball, Cl green ball).

Synthesis and crystallization
A solution of Na 2 [P 5 (SitBu 3 ) 3 ] (0.1 mmol) in 1 mL THF was treated with a solution of [Ag(NHC)Cl] (0.21 g, 0.4 mmol) 2 mL THF. The reaction mixture was stirred for 18 h at room temperature. After overlaying the THF solution with cyclohexane (6 mL), colourless block-like crystals of the title compound were obtained after 10 days at room temperature (yield: 41%).

Refinement details
Crystal data, data collection and structure refinement details are summarized in Table 2. The C-bound H atoms were fixed geometrically and refined using a riding model approximation: C-H = 0.95-1.00 Å with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for other H atoms. One isopropyl group (atoms C481/C482 and C483/C484) is disordered over two sets of sites with an occupancy ratio of 0.447 (17):0.553 (17) while the THF molecule is disordered over two positions with an occupancy ratio of 0.589 (6):0.411 (6). Symmetry-equivalent bond lengths and angles in the two THF sites were restrained to be equal, distance C73 0 Á Á ÁC75 0 was restrained to 2.30 (1) Å , and the displacement parameters of the C atoms were restrained to an isotropic behaviour.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.