198975-58-5Relevant academic research and scientific papers
High-pressure NMR investigation of the intermediates of platinum-phosphine hydroformylation catalysts
Kegl, Tamas,Kollar, Laszlo,Radics, Lajos
, p. 249 - 254 (2008/10/08)
The reactions of square-planar alkylplatinum-diphosphine complexes, Pt(Me)(Cl)(bdpp) (1) and Pt(Me)(SnCl3)(bdpp) (2), as well as Pt{CH(COOEt)CH3}(Cl)(dppp) (3) (where bdpp=(2S,4S)-2,4-bis(diphenylphosphino)pentane, dppp=1,3-bis(diphenylphosphino)propane) with carbon monoxide and carbon monoxide/hydrogen mixture have been studied by high pressure NMR. Carrying out the pressurization at 273 K and the measurement of a sample containing 2 at 173 K, a methylplatinum-hydride was detected under 50 bar CO/H2=1/1 pressure in CD2Cl2 which was transferred to [Pt(CH3)(CO)(bdpp]+SnCl3- (2a) and [Pt(COCH3)(CO)(bdpp]+SnCl3- (2b) at room temperature. The platinum complex containing an alkyl stable to β-hydride elimination Pt{CH(COOEt)CH3} (Cl) (dppp) (3) was reacted with carbon monoxide resulting mainly in Pt(dppp)Cl2 and an ionic intermediate analogous to 2a, [Pt{CH(COOEt)CH3}(CO) (dppp)] +Cl- (3a). However, the same reaction with the in situ formed SnCl2-inserted product, Pt{CH(COOEt)CH3}(SnCl3) (dppp) yielded [Pt(CH3) (CO) (dppp)] +SnCl3- (4a) as a minor component besides PtCl2(dppp) and the decomposition product Pt(Me) (Cl) (dppp) (1′).
