159602-35-4Relevant academic research and scientific papers
Tetranuclear platinum phosphido complexes with different structures
Fornies, Juan,Fortuno, Consuelo,Gil, Reyes,Martin, Antonio
, p. 9534 - 9541 (2005)
The addition of [NBu4]Br or [NBu4][BH4] to solutions of [Pt4(μ-PPh2)4(C 6F5)4(CO)2] (3) yields the complexes [NBu4]2-[Pt4(μ-PPh2) 4(μ-X)2(C6F5)4] (X = Br, 4; H, 5) in which the two CO groups have been replaced by two anionic, bridging X ligands. The total valence electron counts are 64 and 60, respectively; thus, complex 4 does not require Pt-Pt bonds, while two metal-metal bonds are present in 5, as their NMR spectra confirm. Also, the NMR spectra indicate a nonsymmetrical Pt(μ-PPh2) 2Pt(μ-PPh2)(μ-X)Pt(μ-PPh2)(μ-X) Pt disposition for 4 and 5. Treatment of 5 with HX (X = Cl, Br) yields the complexes [NBu4]2[Pt4(μ-PPh 2)4(μ-H)2(C6F5) 3X] (X = Cl, 6; Br, 7). These complexes react with [Ag(OClO 3)PPh3] with displacement of the halide and formation of [NBu4][Pt4(μ-PPh2)4(μ-H) 2(C6F5)3-PPh3] (8). Complexes 6-8 maintain the same basic skeleton as 5, with two Pt-Pt bonds. Complex 4 is, however, an isomer of the symmetric [NBu4] 2[{(C6F5)2Pt(μ-PPh 2)2Pt(μ-Br)}2] (9), which has been prepared by a metathetical process from the well-known [NBu4] 2[{(C6F5)2Pt(μ-PPh 2)2Pt(μ-Cl)}2] (1). The comparison of the X-ray structures of 4 and 9 confirms the different disposition of the bridging ligands, and their main structural differences seem to be related to the size of Br- and its position in the skeleton.
