Alkylation of Arenes Without Chelation Assistance: Transition Metal Catalysts with d ⁶ Electron Configurations

Mechanistic Studies of Single-Step Styrene Production Catalyzed by Rh Complexes with Diimine Ligands: An Evaluation of the Role of Ligands and Induction Period

“…The development of transition metal-catalyzed single-stage oxidative alkenylation of arenes offers potential advantages. Although a variety of transition metal catalysts have been designed to achieve the net addition of an aromatic C–H bond across olefinic CC bonds (i.e., olefin hydroarylation) to synthesize alkyl aromatics, − examples of the direct conversion of benzene (or related arenes such as toluene or xylenes) and unfunctionalized olefins to alkenyl arenes are rare. ,− Reported catalysts are generally based on rhodium, ruthenium, platinum, or palladium, and they are often limited by low selectivity, low yield, poor catalyst longevity, and the use of non air-recyclable oxidants. ,, …”

“…24,39−48 Reported catalysts are generally based on rhodium, ruthenium, platinum, or palladium, and they are often limited by low selectivity, low yield, poor catalyst longevity, and the use of non air-recyclable oxidants. 19,49,50 Previously, our group reported a Rh(I) complex ( Fl DAB)-Rh(TFA)(η 2 -C 2 H 4 ) ( Fl DAB = N,N′-bis(pentafluorophenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene; TFA = trifluoroacetate) that serves as a catalyst precursor for the direct oxidative conversion of benzene and ethylene to styrene with over 800 turnover number (TON) and quantitative yield relative to the air-recyclable Cu(II) oxidant (Scheme 1a). 51,52 We also reported that the simple Rh(I) salt, [Rh(μ-OAc)(η 2 -C 2 H 4 ) 2 ] 2 , can catalyze the oxidative reaction of α-olefins and arenes to produce alkenyl arenes using Cu(OAc) 2 as the oxidant with up to 10:1 linear:branched product ratio and >1470 total catalytic turnovers (Scheme 1b).…”

Self‐Supporting Electrodes for Gas‐Involved Key Energy Reactions

“…A series of transition metal-based catalysts (e.g., metal oxides, phosphides, chalcogenides, and hydroxides) have been widely explored as promising alternatives for next-generation electrocatalysts because of their low-cost merits. [16][17][18][19][20] Besides, there is a perfect match for transition metal-based materials serving as electrocatalysts: I, unique d electron configurations favor the mass desorption process and then enhance the catalytic reaction rate; [21] II, the low cost and adequate resource nature is conducive to scalable production; III, synergistic effect of multi-metal atoms; and IV, excellent stability especially in alkaline media. According to the recent progress, morphologies, structural, and electrode preparation technologies are key parameters for the improvement of integrate electrochemical performances.…”

Effects of Additives on Catalytic Arene C–H Activation: Study of Rh Catalysts Supported by Bis-phosphine Pincer Ligands

“…Catalytic functionalization of carbon–hydrogen (C–H) bonds offers potential applications including the conversion of hydrocarbons to higher value commodity chemicals as well as the development of new methodologies for producing fine chemicals. − However, challenges remain in the field of selective transformation of C–H bonds to functionalized C–C or C–X (X = heteroatom or halogen) bonds. − For example, the high bond dissociation energies and the nonpolar nature of C–H bonds of hydrocarbons make both heterolytic and homolytic C–H bond cleavage challenging. − Discrete C–H activation reactions are often thermodynamically disfavored, which can negatively impact the kinetics of catalytic processes that are overall thermodynamically favorable. , Also, the C–H bonds of the functionalized products are often weaker than those of starting reagents; hence, functionalized products are often more reactive than starting hydrocarbons. ,,, …”