A Triad of Bis(orthometalated) d8-Complexes Containing Four-Membered Rings

Reaction of 2-LiC6F4PPh2 with [MCl2(SEt2)2] in diethyl ether gives the monomeric bis(chelate) complexes trans-[M(κ2-2-C6F4PPh2)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-...

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Veröffentlicht in:Organometallics 2008-10, Vol.27 (20), p.5361-5370
Hauptverfasser: Bennett, Martin A, Bhargava, Suresh K, Keniry, Max A, Privér, Steven H, Simmonds, Peta M, Wagler, Jörg, Willis, Anthony C
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Sprache:eng
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Zusammenfassung:Reaction of 2-LiC6F4PPh2 with [MCl2(SEt2)2] in diethyl ether gives the monomeric bis(chelate) complexes trans-[M(κ2-2-C6F4PPh2)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-C6F4PPh2)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-C6F4-2-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 (4 J PF), in the range 75−95 Hz, between the fluorine atoms (F6) ortho to the metal−carbon σ-bond and the phosphorus atoms of the PPh2 groups, possibly because F6 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-C6F4PPh2 rings. Carbon monoxide inserts into a nickel−carbon σ-bond of 3 to give, after oxidation, bis-2,2′-(diphenylphosphinoyl)octafluorobenzophenone, {2,2′-C6F4P(O)Ph2}2CO (14). The molecular structures of complexes 1−3, 6, 8, 9, and 14 have been determined by single-crystal X-ray methods.
ISSN:0276-7333
1520-6041
DOI:10.1021/om8004806