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Novel Ni(0)-COT Complexes, Displaying Semiaromatic Planar COT Ligands with Alternating C−C and CC Bonds

1997; American Chemical Society; Volume: 119; Issue: 16 Linguagem: Inglês

10.1021/ja964210g

1943-2984

Ingrid Bach, Klaus‐Richard Pörschke, Bernd Proft, Richard Goddard, Carsten Kopiske, Carl Krüger, Anna Rufińska, Klaus Seevogel,

Advanced NMR Techniques and Applications

Reaction of (R2PC2H4PR2)Ni(C2H4) with COT gives the mononuclear complexes (R2PC2H4PR2)Ni(η2-C8H8) (R = iPr 1a, tBu 1b). The COT ligand in 1a,b is planar with alternating C−C and CC bonds, corresponding to a formal semiaromatic [C8H8]- ligand. Reactions of 1a with (iPr2PC2H4PiPr2)Ni(η2,η2-C6H10) and of 1b with stoichiometric amounts of {(tBu2PC2H4PtBu2)Ni}2(μ-C6H6) or lithium afford the dinuclear complexes {(iPr2PC2H4PiPr2)Ni}2{μ-η4(1,2,5,6):η4(3,4,7,8)-C8H8} (2a) and {(tBu2PC2H4PtBu2)Ni}2(μ-η2:η2-C8H8) (2b; two isomers). The COT ligand in 2a is tub-shaped and olefinic, whereas in 2b (as in 1a,b) it is planar and semiaromatic. The products are characterized by IR, solution and solid-state NMR spectroscopy, and by X-ray structure analysis.