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

Abstract

AbstractThe „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 PtLII edge. Parallel investigations were carried out on Pt* obtained from PtCl2 and (9,10–dihydro‐9,10‐an‐thracenediyl)tris(tetrahydrofuran)magnesium (MgA), and on 2 obtained from Pt*, MgA, and MgCl2. The EXAFS results suggest that Pt* consists of extremely small particles (≈ 5–11 Å) with strongly reduced Pt–Pt distances compared to bulk Pt (≈ 0.09 Å). 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 Å). These results suggest that 2 consists of very small Pt–Mg clusters and confirm their formation from organomagnesium reagents and PtCl2 or Pt*.