| Abstract
| - The reactivity of the tetranuclear metalated palladium compound {Pd[μ2-(C6H4)PPh2]Br}4 with different ligands confirmed the ability of the ligand [(C6H4)PPh2]- to expand a bridging or a chelating coordination mode. Bulky phosphines favor the chelating coordination (B, C) while small phosphines like PMe3 give dinuclear compounds with bridging [(C6H4)PPh2]- ligands (A).
- The reactivity of the tetranuclear metallated palladium compound {Pd[μ2-(C6H4)PPh2]Br}4 (1) with different ligandshas been investigated with the aim of evaluating the influence of the entering ligand on the nature of the reactionproducts. The results confirmed the ability of the ligand [(C6H4)PPh2]- to expand a bridging [μ2-] or a chelating[η2-] coordination mode, depending on the auxiliary ligands present in the complex. Bulky phosphines stabilizemononuclear species of formula {Pd[η2-(C6H4)PPh2]Br[P]}, with a four-atom metallocycle, while small phosphinesgive dinuclear compounds. The molecular structures of three different metalated palladium compounds have beendetermined by single-crystal X-ray crystallography; the tetranuclear {Pd[μ2-(C6H4)PPh2]Cl}4 (2), the dinuclear{Pd[μ2-(C6H4)PPh2]Br[PMe3]}2 (3), and the mononuclear {Pd[η2-(C6H4)PPh2]Br[PCBr]}, (PCBr = P(o-BrC6H4)Ph2) (9) were obtained, the first one by halogen exchange reaction and the others by frame degradation of 1.
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