Received 19 May 2006
The structure of the cyclomercurated 2-phenyliminophenyl title compound, [Hg(C14H12N)2], shows that the mercury coordination is essentially square planar
The structure of the title compound, (I), is shown in Fig. 1. Organomercurials are often used as transmetallation reagents in the synthesis of organometallic complexes (Roper & Wright, 1977). Several years ago we reported a synthetic route for the preparation of a range of functionalized 1-mercurio-2-phenyliminophenyls (Flower et al., 2002) and from the structural data obtained concurred with a previous report of Batsanov (1998) that the van der Waals radius of mercury is in the range 2.0-2.2 Å, rather than the often quoted value of 1.55 Å (Bondi, 1964). Here, and in the following paper (Flower & Pritchard, 2006), we report two additional structures of this type of compound. All of the bond lengths and angles in the two structures are as expected. The Hg-N distances in (I) and bis-2-(2-isopropylphenylimnophenyl)mercury, (II), range from 2.787 (10) to 2.850 (10) Å and are comfortably within the sum of the van der Waals radii (3.5-3.7 Å), if the van der Waals radius of Hg is considered to be 2.0-2.2 Å, indicating significant Hg-N interactions. This gives rise to an overall distorted square-planar geometry at Hg in both cases. Other examples of square planar HgII complexes are known (Balasubramani et al., 2005; Haid et al., 2003; Cheng et al., 1994).
| || Figure 1 |
The molecular structure of (I), showing the atomic numbering scheme. Displacement ellipsoids are shown at the 30% probability level.
Caution: preparation of an organomercurial. Organomercurials are extremely toxic. To Hg(C6H4-2-CHO)2 (1 g, 2.4 mmol) dissolved in ethanol (10 ml) containing p-toluenesulfonic acid (10 mg, 0.05 mmol) was added 2-methylaniline (0.56 g, 6 mmol) and the solution was refluxed for 5 h, during which time white crystals of (I) precipitated. The crystalline material was collected by filtration, washed with water and dried in a desiccator. Yield 0.93 g, 68%. An analytically pure sample was obtained through recrystallization from hot ethanol, and crystals suitable for the diffraction study were grown by dissolving approximately 10 mg of (I) in CH2Cl2 (0.2 ml) in a small vial (1 × 5 cm), layering ethanol (5 ml) on top and leaving the vial to to stand for 24 h. Elemental analysis C28H24HgN2 requires: C 57.56, H 4.11, N 4.76%; found: C 57.79, H 4.22, N 4.91%.
H atoms were positioned geometrically and treated as riding, with C-H = 0.93 and 0.96 Å, and with Uiso(H) values of 1.2 and 1.5 times Ueq(C). The highest residual peak is located 1.03 Å from Hg1 and deepest hole is located 0.92 Å from Hg1..
Data collection: COLLECT (Nonius, 2000); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
We thank the EPSRC Crystallographic Service, University of Southampton, for collecting the data.
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