Oxygen Insertion into Metal Carbon Bonds: Formation of Methylperoxo Pd(II) and Pt(II) Complexes via Photogenerated Dinuclear Intermediates

Abstract

Platinum(II) and palladium(II) complexes [M(CH3)(L)]SbF6 with substituted terpyridine ligands L undergo light-driven oxygen insertion reactions into metal methyl bonds resulting in methylperoxo complexes [M(OOCH3)(L)]SbF6. The oxygen insertion reactions occur readily for complexes with methyl ligands that are activated due to steric interaction with substituents (NH2, NHMe or CH3) at the 6,6″-positions on the terpyridine ligand. All complexes exhibit attractive intermolecular π···π or M···M interactions in the solid state and in solution, which lead to excited triplet dinuclear M-M complexes upon irradiation. A mechanism is proposed whereby a dinuclear intermediate is generated upon irradiation that has a weakened M-C bond in the excited state, resulting in the observed oxygen insertion reactions.

A DFT-based mechanistic proposal for the light-driven insertion of dioxygen into Pt(ii)–C bonds

“…These results favour a monometallic pathway, in contrast to previous suggestions that photoexcitation and oxygen quenching take place through a bimetallic mechanism involving two complex molecules in the form of a dimer. 13 Our calculations show that once 3 A is formed, coordination of dioxygen takes place without the need for a second complex. We confirmed this conclusion through calculations on the bimolecular mechanism reported in the ESI.…”

“…Recently, Britovsek et al 13 – 15 and Goldberg et al 16 – 18 reported that platinum methyl complexes can insert dioxygen to give the methylperoxo product. One of the remarkable aspects of the reaction reported by Britovsek was the strong dependence of the insertion on the substituents in the 6 and 6′ positions of the terpyridine ligand ( Fig.…”

Progress on the Photocatalytic Organic Hydrogen-Evolution Coupling/Aromatization Reaction

“…图式 14 光催化偶联放氢合成芳基唑类化合物 Scheme 14 Photocatalytic hydrogen-evolution coupling synthesis of aryl azoles 咪唑并吡啶是重要的稠合双环 5～6 元杂环结构, 在药物化学中被广泛应用 [50,51] . 雷爱文课题组 [52] 由于金属与氧元素的 HOMO 和 LUMO 之间较高的 能垒, C-H 官能化形成 C-O 键在金属催化中受到的关 注较少 [59] . 近年来, 过渡金属催化的羧酸的氧化脱氢交 叉偶联技术推进了 C-O 键的构建, 但必须加入氧化剂 和牺牲剂限制了反应的适用性 [60,61] .…”

Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex

“…Similar 6,6′′‐substituted terpyridines containing weaker pendent H‐bond donor amine groups have been reported previously with R=NH 2 , NH(CH 3 ), NH(C 2 H 5 ) . However, their associated coordination chemistry is limited to three reports using Pt and Pd ,…”