Catalytic Borylation of Methane: Combining Computational and High‐Throughput Screening Approaches to Discover a New Catalyst

Zatsepin, Pavel; Sorsche, Dieter; Ahn, Seihwan; Baik, Mu‐Hyun; Mindiola, Daniel J.

doi:10.1002/9781119379256.ch17

Cited by 1 publication

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“…The Ir(III)trisboryl is then regenerated following reaction with B 2 Pin 2 (Scheme 1). This has also been supported computationally 23,25,27,45,47 and is hypothesized to be the mechanistic pathway with other organometallic iridium complexes as well. 27,34 Computational investigation of the borylation mechanism in an Ir catalyst immobilized in a MOF has also been carried out.…”

Section: ■ Introductionmentioning

confidence: 55%

“…The Ir(III)trisboryl is then regenerated following reaction with B 2 Pin 2 (Scheme ). This has also been supported computationally ,,,, and is hypothesized to be the mechanistic pathway with other organometallic iridium complexes as well. , …”

Section: Introductionmentioning

confidence: 59%

“…Since the report of these seminal examples, investigation has continued into optimization of borylation systems through ligand modification and expansion to other classes of substrates, beyond arenes. − ,,− In particular, efforts have expanded to functionalizing light alkanes such as methane, which is particularly difficult due to the chemical inertness of the C–H bonds. Sanford and co-workers contemporaneously with Smith, Baik, and Mindiola and co-workers reported the borylation of methane using iridium catalysts in combination with ligands such as 1,10-phenanthroline derivatives (Figure C). , At 150 °C and high pressures of methane in the presence of B 2 Pin 2 , a mixture of monoborylated and diborylated products could be obtained. , …”

Section: Introductionmentioning

confidence: 99%

“…As catalytic competency for borylation has been widely demonstrated with organometallic iridium catalysts, interest has grown in the mechanism of these processes. In the molecular, N , N -ligand/Ir(I) systems, Hartwig and others, through extensive kinetic study and structural characterization, ,,,,,,,,,,− proposed the catalytic cycle depicted in Scheme . A five coordinate Ir(III)trisboryl active intermediate, which is generated from dissociation of COE (COE = cyclooctene) from the metal center, can activate the arene substrate through oxidative addition or σ-bond metathesis, with the former being more likely (Scheme ).…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic Insights into C–H Borylation of Arenes with Organoiridium Catalysts Embedded in a Microporous Metal–Organic Framework

et al. 2020

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Organometallic iridium catalysts can be used in conjunction with bispinacolatodiboron (B 2 Pin 2 ) to effect the borylation of a variety of substrates such as arenes, alkanes, heteroarenes, and oxygenates. Recently, efforts have also focused on integrating these catalysts into porous supports, such as metal−organic frameworks (MOFs). While the mechanism of homogeneous borylation systems has been thoroughly investigated experimentally and computationally, analogous studies in MOF-supported iridium catalysts have not been conducted. Herein, we report the mechanistic investigation of a phenanthroline-iridium catalyst immobilized in the organic linker of Universitetet i Oslo (UiO)-67 (Zr 6 O 4 (OH) 4 (BPDC) 4 (PhenDC) 2 , BPDC = biphenyl-4,4′-dicarboxylate, PhenDC = 1,10-phenanthroline-4,4′-dicarboxylate). By using benzene as a model substrate, variable time normalization analysis (VTNA) of the kinetic data suggested a rate law consistent with zero-order in B 2 Pin 2 , and first-order in arene. A primary kinetic isotope effect (KIE) in the time course of benzene-d 6 borylation also provided complementary information about the role of the arene in the rate-determining step of the reaction. Characterization by techniques such as X-ray absorption spectroscopy (XAS) confirmed the presence of Ir(III), while pair distribution function (PDF) analysis suggested structures containing an Ir−Cl bond, further substantiated by X-ray photoelectron spectroscopy (XPS). Analysis of postcatalysis materials by inductively coupled plasma− optical emission spectroscopy (ICP-OES) revealed low boron accumulation, which may indicate an absence of boron in the resting state of the catalyst. Finally, in comparing borylation of benzene and toluene, a slight selectivity for benzene is observed, which is similar to the analogous homogeneous reaction, indicating the influence of substrate sterics on reactivity.

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