1064709-99-4Relevant academic research and scientific papers
A triad of bis(orthometalated) d8-complexes containing four-membered rings
Bennett, Martin A.,Bhargava, Suresh K.,Keniry, Max A.,Priver, Steven H.,Simmonds, Peta M.,Wagler, Joerg,Willis, Anthony C.
, p. 5361 - 5370 (2009/02/08)
Reaction of 2-LiC6F4PPh2 with [MCl 2(SEt2)2] in diethyl ether gives the monomeric bis(chelate) complexes trans-[M((κ2-2-C6F 4PPh2)2] [M = Pt (1), Pd (2)] or, in the case of platinum, a mixture of cis-and trans-isomers. Treatment of a mixture of NiCl2 and 2-BrC6F4PPh2 in THF with zinc dust gives trans-[Ni(κ2-2-C6F 4PPh2)2] (3). The four-membered chelate rings in 1-3 are opened on addition of the bidentate ligand 1,2-bis(diphenylphosphino) ethane (dppe), and, in the case of 3, 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen), to give complexes of the type cis-[M(κC-C 6F4-2-PPh2)2(L-L)] [L-L = dppe, M = Ni (6), Pd (7), Pt (8); M = Ni, L-L = bipy (9), phen (10)], in which the PPh2 groups are uncoordinated. Complexes 6-8 show unexpectedly large four-bond coupling constants (4JPF), in the range 75-95 Hz, between the fluorine atoms (F6) ortho to the metal-carbon a-bond and the phosphorus atoms of the PPh2 groups, possibly because F 6 and the lone pairs on phosphorus adopt a close to synperiplanar conformation. Treatment of 2 with [PdCl2(NCMe)2] gives the dinuclear complex [Pd2(μ-Cl)2(κ2-2- C6F4PPh2)2] (11), which dimerizes in solution to the tetranuclear complex [Pd4(μ-Cl) 4(μ-2-C6F4PPh2)4] (12) as a result of opening of the chelate 2-C6F4PPh 2 rings. Carbon monoxide inserts into a nickel-carbon a-bond of 3 to give, after oxidation, bis-2,2′-(diphenylphosphinoyl) octafluorobenzophenone, (2,2′-C6F4P(O)Ph 2}2CO (14). The molecular structures of complexes 1-3,6,8, 9, and 14 have been determined by single-crystal X-ray methods.
