121472-29-5Relevant academic research and scientific papers
Synthesis off new metallacycles of rhenium(VII) oxides: Migration of a Me3Si group to form the cis-dioxo cyclometallaphosphoranimino phosphane NPPh2CH2PPh2Re(O)2(OSiMe 3)2 and arsane NPPh2(CH2)2AsPh2Re(O) 2(OSiMe3)2
Katti, Kattesh V.,Cavell, Ronald G.
, p. 3033 - 3036 (2008/10/08)
The new bifunctional phosphoranimino phosphane ligand Me3SiN=PPh2CH2PPh2 (1) and its arsane analogue Me3SiN= PPh2CH2CH2AsPh2 (3) react with Me3SiOReO3 to form metallacycles NPPh2CH2PPh2Re(O)2(OSiMe 3)2 (2) and NPPh2CH2CH2AsPh2Re(O) 2(OSiMe3)2 (4) in high yield via migration of a SiMe3 group to a terminal oxygen on Re. The P(V) phosphorus atom is highly deshielded in these complexes (σ(31P) 37-39 ppm), suggesting significant delocalization of electron density in the Re-N=P framework. 29Si (INEPT) NMR spectroscopy shows two singlets (17.11, 7.46 ppm (2); 18.17, 8.25 ppm (4)) with no coupling to phosphorus. In each case a cis-dioxo structure is proposed. Reaction of 1 with Re2O7 gave a mixture of products, 2 and a species identified as a dimer with a ReORe bridge (5). Treating this mixture with (Me3Si)2O converted the dimer to 2. Parallel reaction of the doubly oxidized phosphoranimine Me3SiN=PPh2CH2PPh2=NSiMe3 with Me3SiOReO3 gave only complex mixtures.
