Spin‐Selective, Competitive Hydrogen‐Atom Transfer versus CH₂O‐Generation from the CH₄/[ReO₄]⁺ Couple at Ambient Conditions

Abstract

The thermal gas-phase reactions of [ReO ] with methane have been explored by using Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry complemented by high-level quantum chemical calculations. Upon reacting with methane, this cluster oxide, having an even-number of valence electrons, brings about both hydrogen-atom abstraction (HAT) to generate [ReO H] and the formation of formaldehyde. Mechanistically, HAT occurs on the ground-state triplet surface, while for the generation of formaldehyde a two-state reactivity scenario prevails. The branching ratio of these competing processes is affected by the rather inefficient spin-orbit coupling to bring about the required triplet-singlet intersystem crossing.

Photo-control of bimolecular reactions: reactivity of the long-lived Rhodamine 6G triplet excited state with ˙NO

“…It also points out the potential of gas-phase approaches to explore photo-chemistry in general. There is a rich history of studying the gas-phase ion-molecule reactions of atomic and small molecular cations that are electronically and/or vibrationally excited and state selected (see for lead references [19][20][21][22][23][24][25][26][27][28][29][30][31] ). However, here, we take advantage of this long gas-phase life-time to provide one of the first examples where the chemistry of singlet and triplet forms This journal is © The Royal Society of Chemistry 20xx…”

Methane Activation by [AlFeO3]+: the Hidden Spin Selectivity

“…For example, a series of diatomic metal oxide cation clusters [MO] + (M=Fe, [4] Cu, [5] Au, [6] Zn, [7] Co, [8] Ni, [9] Pd [9] ) are capable of oxidizing methane to methanol; in addition, [ReO 3 ] + , [10] [RuO 3 ] + , [11] [PtO 2 ] + , [12] [RhAl 3 O 4 ] + , [RhAl 2 O 4 ] À , [13] [RhTiO 2 ] À , [14] [Rh 2 VO x ] À [15] react with methane to generate CO. However, for the direct conversion of methane to formaldehyde, only monometallic oxide clusters[CrO 2 ] + , [16] [TaO 3 ] + , [17] [ReO 4 ] + , [18] [Al 2 O 3 ] + [19] and heteronuclear metal oxide clusters [PtAl 2 O 4 ] À , [20] [AuTi 3 O 8 ] + , [21] [AuNbO 3 ] + , [22] [AuV 2 O 6 ] + , [23] [AlVO 4 ] + [24] and [AlNiO 3 ] + [25] have been proven to achieve that. In general, the doping of noble metals like Pt and Au will provide more efficient active sites and driving force for the direct conversion of methane to formaldehyde.…”