{2,6-Bis[(diphenylphosphanyl)oxy]phenyl-κ3 P,C 1,P′}iodidonickel(II)

In the title complex, [Ni(C30H23O2P2)I], the divalent Ni atom is coordinated by two P atoms and one C atom from the 1,3-bis[(diphenylphosphanyl)oxy]benzene ligand; the distorted square-planar geometry is completed by an iodide ligand. The largest distortions from ideal square-planar geometry are reflected in the P—Ni—P angle of 164.20 (2)° and the P—Ni—C angles of 82.09 (6) and 82.11 (6)°. The rather short Ni—C bond length [1.890 (2) Å] is anticipated in light of the much stronger trans influence of the aryl moiety compared to the iodide ligand. The P-bound phenyl rings adopt different orientations to minimize steric repulsion among themselves.

In the title complex, [Ni(C 30 H 23 O 2 P 2 )I], the divalent Ni atom is coordinated by two P atoms and one C atom from the 1,3bis[(diphenylphosphanyl)oxy]benzene ligand; the distorted square-planar geometry is completed by an iodide ligand. The largest distortions from ideal square-planar geometry are reflected in the P-Ni-P angle of 164.20 (2) and the P-Ni-C angles of 82.09 (6) and 82.11 (6) . The rather short Ni-C bond length [1.890 (2) Å ] is anticipated in light of the much stronger trans influence of the aryl moiety compared to the iodide ligand. The P-bound phenyl rings adopt different orientations to minimize steric repulsion among themselves.

Comment
Recently, much attention has been paid to the chemistry of pincer complexes (Leis et al. 2008;Dijkstra et al. 2001;Naghipour et al. 2007;van der Boom et al. 2003;Nishiyama 2007). These compounds have found applications as promising materials and highly versatile catalysts. Here we report the crystal structure and the synthesis of{m-(Ph 2 PO) 2 C 6 H 3 }NiI. The formation of the title complex was serendipitous in that the original goal of the synthesis was to prepare the corresponding methyl derivative {m-(Ph 2 PO) 2 C 6 H 3 }Ni(CH 3 ). To our surprise, reaction of the bromo precursor with the Grignard reagent MeMgI gave instead the iodo derivative. It appears that the target methyl complex is not sufficiently stable, undergoing a salt metathesis with MgX 2 (X= Br or I) to furnish the iodo derivative. As shown in Fig. 1, the Ni(II) center in the title complex exists in the center of a square plane defined by the donor atoms P1 and P2, the iodide ligand, and the carbon atom of the aromatic moiety of the pincer ligand. Despite the rigid meridional coordination of the tridentate pincer-type ligand, a slight distortion is evident in the solid state of this complex from the P-Ni-P angles of 82.09 (6) and 82.11 (6)°; such distortions are commonly found in this family of Ni(II) pincer complexes (van der Boom et al. 2003).

Experimental
Transfer of MeMgI (0.12 ml of a 3.0 M solution in THF, 0.24 mmol) to a stirred solution of {m-(Ph2PO)2 C6H3}NiBr(50 mg, 0.08 mmol) in dry and degassed toluene (1.5 ml) caused an immediate color change from deep yellow to a red orange.
The resulting mixture was stirred under an inert atmosphere of nitrogen for 15 min and was then filtered through cellulose.
Evaporation of the solvent gave an orange solid. Single crystals suitable for X-ray diffraction studies were grown by slowly diffusing hexane into a saturated toluene solution.

Refinement
All hydrogen atoms were positioned geometrically and refined as riding, with C-H = 0.93 Å, and U iso (H) = 1.2 U eq (C). Fig. 1