X-Ray Structural Analysis of NiII, PdII, and PtII Complexes with the Potentially Tridentate Ligand 1,3-Bis(diphenylphosphinomethyl)benzene, 1,3-C6H4(CH2PPh2)2

The ligand 1,3-bis(diphenylphosphinomethyl)benzene, 1,3-C₆H₄(CH₂PPh₂)₂ undergoes cyclometalation reactions, thus forming derivatives containing the tridentate moiety 2,6-bis(diphenylphosphinomethyl)phenyl,2,6-C₆H₃(CH₂PPh₂)₂. Complexes of the type trans-[MBr(C₆H₃CH₂PPh₂₂)] with M = Ni^II, Pd^II, and Pt^II could be obtained and their crystal structures were here determined by X-ray diffraction (XRD) methods. The Ni complex belongs to the space group P2₁/c with a = 10.257(2), b = 16.234(5), c = 17.475(4) Å, = 109.34(2), and Z = 4. The Pd complex belongs to the space group P2₁/n with a = 10.325(3), b = 16.279(4), c = 17.303(4) Å = 105.34(3), and Z = 4. The Pt complex belongs to the space group P2₁/n with a = 10.127(2), b = 14.776(2), c = 19.023(3) Å, = 91.01(1), and Z = 4. Different distortions are induced by the rigid tridentate ligand on the square planar coordinations of the three metals. A significant difference between the two M-P bond distances is present in the Pt complex and can also be found in an analogous Pd complex.