Inorganic Chemistry, Vol.47, No.13, 5978-5987, 2008
Halide addition/abstraction in phosphido derivatives: Isolation of the thallium and silver intermediates
Reaction of unsaturated (44e(-) skeleton) [PdPt2(mu-PPh2)(2)(mu-P2Ph4)(R-F)(4)] 4 with Br- produces the saturated (48e(-) skeleton) complex [NBU4][(R-F)(2)Pt(mu-PPh2)(mu-Br)Pd(mu-PPh2)(mu-P2Ph4)Pt(RF)(2)] 5 without any M-M' bond, Attempts to eliminate Br- of 5 with Ag+ in CH2Cl2 as a solvent gives a mixture of [(R-F)(2)Pt-III(mu-PPh2)(2)Pt-III(RF)(2)] and some other unidentified products as a consequence of oxidation and partial fragmentation. However, when the reaction of 5 with Ag+ is carried out in CH3CN, no oxidation is observed but the elimination of Br- and the formation of [(RF)(2)(CH3CN)Pt(mu-PPh2)Pd(mu-PPh2)(mu-P2Ph4)Pt(R-F)(2)] 6 (46e(-) skeleton), a complex with a Pt-Pd bond, takes place. It is noteworthy that the reaction of 5 with TIPF6 in CH2Cl2 does not precipitate TIBr but forms the adduct [(RF)(2)PtTl(mu-PPh2)(mu-Br)Pd(mu-PPh2)(mu-P2Ph4)Pt(R-F)(2)] 7 with a Pt-TI bond. Likewise, 5 reacts with [AgOClO3(PPh3)] in CH2Cl2 forming the adduct [AgPdPt2(mu-Br)(mu-PPh2)(2)(mu-Ph2P-PPh2)(R-F)(4)(PPh3)] 8, which contains a Pt-Ag bond. Both adducts are unstable in a CH3CN solution, precipitating TIBr or AgBr and yielding the unsaturated 6. The treatment of [NBu4](2)[(R-F)(2)Pt(mu-PPh2)(2)Pd(mu-PPh2)(2)Pt(R-F)(2)] in CH3CN with I-2 (1:1 molar ratio) at 233 K yields a mixture of 4 and 6, which after recrystallization from CH2Cl2 is totally converted in 4. If the reaction with I-2 is carried out at room temperature, a mixture of the isomers [NBu4][(R-F)(2)Pt(mu-PPh2)(mu-I)Pd(mu-PPh2)(mu-P2Ph4)Pt(R-F)(2)] 9 and [NBu4][(R-F)(PPh2RF)Pt(mu-PPh2)(mu-I)Pd(mu-PPh2)(2)Pt(R-F)(2)] 10 are obtained. The structures of the complexes have been established on the bases of NMR data, and the X-ray structures of 5-8 have been studied. The relationship between the different complexes has been studied.