A new series of transition-metal-?-arene complexes has been prepared by a metal atom synthetic method.The deposition of Ni vapor, C6F5Br, and arenes has prodused high yields of (C6F5)2Ni-?-arene complexes.A variety of ?-arene ligands are η 6 bound by the (C6F5)2Ni moiety, resulting in soluble highly labile materials, where the ?-arene ligand is exchangeble at room temperature.These complexes have not been isolable when ?-bonding ligands other then C6F5 have been employed.The formation of the ?-toluene complex proceeds through a pseudostable C6F5NiBr species that can be trapped at -80 deg C with R3P but decomposes by reductive elimination of CF5-CF5 in the absence of R3P or electron-rich arenes.It is likely that C6F5NiBr-?-arene is formed initially, which then disproportionates to (C6F5)2Ni-?-arene and NiBr2.Due to the high lability of the ?-arene ligand, these complexes possess a rich chemistry.Displacement of the ?-arene ligand can bee carried out cleanly and in high yield by P(Et)3,...
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