Advantages of Chelating Polydentate Ligands

Flexible polyphosphine ligands (e.g., 5-9), which contain either ethylene or trimethylene linkages, have been used to form mononuclear 

If the connecting chain between phosphorus atoms is only one atom (e.g., dppm, 10, HC(PMe2)3, and HC(PPh2)3, H, or CH3Si(PPh2)3, 12), the phosphino units tend to bridge across two metals (see Chapters 4 and 5 for dppm examples). In fact, this bridging tendency has been used to 

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