Investigations of LiP(SiMe2CH2SiMe3)–PtBu2, the Surprising Byproduct in the Metalation of (Me3Si)2P–PtBu2

Abstract

During the metalation reaction of (Me3Si)2P–PtBu2 with nBuLi, a byproduct with the sum formula Li(thf)nP(SiMe2CH2SiMe3)–PtBu2 (2, n = 2.7–1) was detected. The formation of the unexpected substituent SiMe2CH2SiMe3 was investigated, a possible reaction mechanism based on DFT calculations established, and the compound synthesized following an independent route. Compound 2 eliminated thf in vacuo to yield the dimeric [Li(thf)P(SiMe2CH2SiMe3)–PtBu2]2 (2a). Exchange of thf with tmeda [Me2N(CH2)2NMe2] in 2 led to the solvent‐separated ion pair [Li(tmeda)2]+[(SiMe2CH2SiMe3)P–PtBu2]– (4). The solid‐state structures of 2a, 4, and the contact ion pair Li(thf)(tmeda)P(SiMe2CH2SiMe3)–PtBu2 (5) were determined by single‐crystal X‐ray diffraction analysis. Extensive variable‐temperature multinuclear NMR studies were carried out to elucidate the structures of these compounds in solution and to compare them with the solid‐state structures.