From a Trinuclear Platinum(III) Phosphido Derivative to a Platinum(II) Cluster: Formation of a P−C Bond

Reaction of the trinuclear Pt(III)-Pt(III)-Pt(II) [(C6F5)2Pt(III)(mu-PPh2)2Pt(III)(mu-PPh2)2Pt(C6F5)2] (2) derivative with NBu4Br or NBu4I results in the formation of the trinuclear Pt(II) complexes [NBu4][(PPh2C6F5)(C6F5)Pt(mu-PPh2)(mu-X)Pt(mu-PPh2)2Pt(C6F5)2] [X = I (3), Br (4)] through an intramolecular PPh2/C6F5 reductive coupling and the formation of the phosphine PPh2C6F5. The trinuclear Pt(II) complex [(PPh2C6F5)(C6F5)Pt(mu-PPh2)Pt(mu-PPh2)2Pt(C6F5)2] (5), which displays two Pt-Pt bonds, can be obtained either by halide abstraction in 4 or by refluxing of 2 in CH2Cl2. This latter process also implies an intramolecular PPh2/C6F5 reductive coupling. Treatment of complex 5 with several ligands (Br-, H-, and CO) results in the incorporation of the ligand to the cluster and elimination of one (X = H-) or both (X = Br-, CO) Pt-Pt bonds, forming the trinuclear complexes [NBu4][(PPh2C6F5)(C6F5)Pt(mu-PPh2)(mu-X)Pt(mu-PPh2)2Pt(C6F5)2] [X = Br (6), H (7)] or [(PPh2C6F5)(C6F5)Pt(mu-PPh2)2Pt(mu-PPh2)(CO)Pt(C6F5)2(CO)] (8). The structures of the complexes have been established on the basis of 1H, 19F, and 31P NMR data, and the X-ray structures of the complexes 2, 3, 5, and 7 have been established. The chemical relationship between the different complexes has also been studied.