Dehydrogenation of Dimethylamine–Borane Catalyzed by Half-Sandwich Ir and Rh Complexes: Mechanism and the Role of Cp* Noninnocence

Half-sandwich Cp*Rh^III complexes (Cp* = η⁵-1,2,3,4,5-pentamethylcyclopentadienyl) supported by 2,2′-bipyridine or 4,4′-di-<i>tert</i>-butyl-2,2′-bipyridine catalyze dehydrogenation of dimethylamine–borane (Me₂NH·BH₃) to produce H₂ and dimethylamino–borane dimer (Me₂NBH₂)₂ with turnovers of 2200. The Ir^III analogues, on the other hand, display dramatically poorer catalytic activity. Mechanistic inferences drawn from stoichiometric reactions and DFT calculations suggest noninnocent involvement of the Cp* moiety as a proton shuttle

Facile Styrene Formation from Ethylene and a Phenylplatinum(II) Complex Leading to an Observable Platinum(II) Hydride

A new 2-(di-<i>tert</i>-butylphosphanyl)­benzenesulfonate-supported phenylplatinum­(II) complex instantaneously but reversibly binds ethylene at room temperature. Direct and rapid styrene formation at room temperature via insertion of the Pt^II-bound ethylene into the Pt^II–Ph fragment followed by β-hydride elimination results in the formation of a solution-stable Pt^II–H complex. The Pt^II–H fragment is resistant toward protonolysis by acetic acid. Oxidation of the Pt^II–H fragment by excess Cu^II(OTf)₂ leads to an inorganic Pt^II complex incapable of C–H activation

Dehydrogenation of Dimethylamine–Borane Catalyzed by Half-Sandwich Ir and Rh Complexes: Mechanism and the Role of Cp* Noninnocence

Half-sandwich Cp*Rh^III complexes (Cp* = η⁵-1,2,3,4,5-pentamethylcyclopentadienyl) supported by 2,2′-bipyridine or 4,4′-di-<i>tert</i>-butyl-2,2′-bipyridine catalyze dehydrogenation of dimethylamine–borane (Me₂NH·BH₃) to produce H₂ and dimethylamino–borane dimer (Me₂NBH₂)₂ with turnovers of 2200. The Ir^III analogues, on the other hand, display dramatically poorer catalytic activity. Mechanistic inferences drawn from stoichiometric reactions and DFT calculations suggest noninnocent involvement of the Cp* moiety as a proton shuttle

Exclusive Csp³–Csp³ vs Csp²–Csp³ Reductive Elimination from Pt^IV Governed by Ligand Constraints

Selective reductive elimination of ethane (Csp³-Csp³ RE) was observed following bromide abstraction and subsequent thermolysis of a Pt^IV complex bearing both Csp³- and Csp²-hybridized hydrocarbyl ligands. Through a comparative experimental and theoretical study with two other Pt^IV complexes featuring greater conformational flexibility of the ligand scaffold, we show that the rigidity of a meridionally coordinating ligand raises the barrier for Csp²-Csp³ RE, resulting in unprecedented reactivity

Concurrent B‑to-Pt Methyl Migration and B‑Center Retention in Aerobic Oxidation of Methylborato Platinum(II) Complexes

A new anionic methoxy methylbis­(2-pyridyl)­borate ligand enables facile oxidation of the derived dimethylplatinum­(II) complex, <b>10</b>, with O₂ in methanol to produce a mixture of two platinum­(IV) complexes in combined quantitative yield, one supported by a modified ligand, dimethoxybis­(2-pyridyl)­borate, and the second supported by the original methoxy methylbis­(2-pyridyl)­borate. The former product results from the aerobic Pt^II-to-Pt^IV oxidation and B-to-Pt^IV methyl migration with subsequent bridging of the boron and Pt^IV centers by a methoxy group derived from the solvent. A similar reactivity was also demonstrated for <b>11</b>, the methyl methoxo platinum­(II) analogue of <b>10</b>. Factors responsible for the product distribution are discussed