Selective Activation of the C−H Bond in Methane by Single Platinum Atomic Anions

Abstract

Mass spectrometric analysis of the anionic products of interaction between platinum atomic anions, Pt−, and methane, CH4 and CD4, in a collision cell shows the preferred generation of [PtCH4]− and [PtCD4]− complexes and a low tendency toward dehydrogenation. [PtCH4]− is shown to be H−Pt−CH3− by a synergy between anion photoelectron spectroscopy and quantum chemical calculations, implying the rupture of a single C−H bond. The calculated reaction pathway accounts for the observed selective activation of methane by Pt−. This study presents the first example of methane activation by a single atomic anion.

Simultaneous Functionalization of Methane and Carbon Dioxide Mediated by Single Platinum Atomic Anions

“…The methyl and the hydro groups are expected to be reactive to other small molecules, establishing the basis for further methane functionalization. 8 In other studies related to CO 2 activation and hydrogenation, we demonstrate that negatively charged metal atoms, including Pt − , activate CO 2 9,10 and that metal hydrides, especially platinum hydrides, hydrogenate CO 2 into formate. 11,12 On the basis of these findings, we conceive that Pt − is active in both the oxidative methane activation and the reductive CO 2 functionalization and that by coupling such reactivities, Pt − can mediate the mutual transformation of methane and carbon dioxide.…”

“…Methane activation occurred in a laser vaporization source, where the laser ablated Pt – reacted with methane or deuterated methane introduced into the vaporization chamber. The activation products, PtCH 4 – and PtCD 4 – , were, respectively, characterized by anion photoelectron spectroscopy and confirmed as H 3 C–Pt–H – and D 3 C–Pt-D – (Figure S1, ref ). These activation products then reacted with CO 2 added into a reaction cell downstream.…”

“…The reaction starts with the selective activation of one C−H bond in methane by Pt − , which has been extensively studied in our previous work. 8 Therefore, the combined experimental and computational evidence confirms that both CO 2 hydrogenation and C−C bond coupling occur during the reaction. When Pt − activates CH 4 , it is electronically excited in situ to the 4 G(6s 2 5d 8 6p 1 ) state to fulfill the donor−acceptor model for σ-bond activation.…”

Mapping the Electronic Structure of the Uranium(VI) Dinitride Molecule, UN2

“…Photoelectron spectra were calibrated against the well-known atomic lines of the copper anion, Cu – . The UN 2 – anion was generated in a laser vaporization/reaction ion source. , It consisted of a depleted uranium (U-238) rod, which was ablated with second harmonic (60 mJ, 532 nm) photon pulses from a Nd:YAG laser and expanded with 100 psi of an ultrahigh purity helium–10% nitrogen gas mixture. The UN 2 – anion was also generated by expanding a helium–10% ammonia gas mixture over the uranium rod, as it was being laser ablated.…”

Ion spectroscopy in methane activation

“…Recently, the first evidence for methane activation by a metal anion, Pt − , has been reported (Liu et al, 2019). Using photoelectron spectroscopy of the mass-selected [PtCH 4 ] − complex, the authors were able to show that this complex corresponded to an activated methyl platinum hydride [H-Pt-CH 3 ] − species.…”