Investigation of the formation reaction and structural characterization of the 'platinum Grignard reagent' [Pt(MgCl)2(THF)(x)] by extended X-ray absorption fine structure (EXAFS) and other methods

Article abstract of DOI:10.1002/chem.19970031020

The 'platinum Grignard reagent' [Pt(MgCl)₂(THF)(x)] (2), obtained by the reaction of PtCl₂ and Et₂Mg in a 1:2 molar ratio, as well as finely divided platinum (Pt*) a possible intermediate formed during the preparation of 2-have been investigated by EXAFS spectroscopy at the Pt L(III) edge. Parallel investigations were carried out on Pt* obtained from PtCl₂ and (9,10-dihydro-9,10-anthracenediyl)tris(tettrahydrofuran)magnesium (MgA), and on 2 obtained from Pt* MgA, and MgCl₂. The EXAFS results suggest that Pt* consists of extremely small particles (? 5-11 A) with strongly reduced Pt-Pt distances compared to bulk Pt (?0.09 A). The EXAFS spectra of 2 indicate the presence of Mg shells in addition to Pt shells in the Pt environment; Mg atoms are at a bonding distance from Pt atoms (2.78-2.80 A). These results suggest that 2 consists of very small Pt-Mg clusters and confirm their formation from organomagnesium reagents and PtCl₂ or Pt*.