Palladium (II) complexes with mono-oxide 1,1′-bis(diphenylphosphino)metallocene ligands [Fe(η5-C5Me4PPh2)(η5-C5Me4P{O}Ph2)] and [Os(η5-C5H4PPh2)(η5-C5H4P{O}Ph2)]

The monoxides [Fe(η5-C5Me4PPh2)(η5-C5Me4P{O}Ph2)] (1) and [Os(η5-C5H4PPh2)(η5-C5H4P{O}Ph2)] (2) have been prepared by treatment of the corresponding diphosphines with CCl4 and methanol.These ligands react with [Pd(PhCN)2Cl2] to give dichloride complexes of different structure.The dimeric complex [{Os(η5-C5H4PPh2)(η5-C5H4P{O}Ph2)}PdCl(μ-Cl)]2 (4) contains the monodentate P-coordinated osmocene ligand with the free P{O}Ph2 group, while the octamethylferrocene ligand gives the chelate k2-P,O complex [{Fe(η5-C5Me4PPh2)(η5-C5Me4P{O}Ph2)}PdCl2] (3).The structures of 3 and 4 have been determined crystallographically.Treatment of 3 and 4 with silver salts in CH2Cl2 or acetonitrile leads to the corresponding dicationic complexes[{M(η5–C5R4PPh2)(η5-C5R4P{O}Ph2)}Pd(MeCN)x]2+ (5, M = Fe, R = Me; 6, M = Os, R = H). Complex 5 decomposes upon isolation, in contrast 6 is rather stable, probably due to Os–Pd bonding. The dichlorides 3 and 4 catalyze catalytic amination of p-bromotoluene with N-(4-tolyl)morpholine with lower activity than (dppf)PdCl2, however they perform comparable to (dppf)PdCl2 activity in coupling of p-bromotoluene with p-methoxyphenyl boronic acid.