An Information-Rich Graphical Representation of Catalytic Cycles

McFarlane, James; Henderson, Brett; Donnecke, Sofia; McIndoe, J. Scott

doi:10.1021/acs.organomet.9b00563

Cited by 10 publications

(10 citation statements)

References 14 publications

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“…Elemental analysis was performed by Canadian Microanalytical Service Ltd. Electronic absorption spectra were recorded on a Cary 60 UV–vis spectrophotometer using a 3 mL quartz cuvette with 1 cm path length. Catalytic cycles were drawn using a recently reported web-based interface …”

Section: Methodsmentioning

confidence: 99%

Mechanistic Insights into Iron-Catalyzed C–H Bond Activation and C–C Coupling

et al. 2021

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Iron-catalyzed C−C coupling reactions of pyrrole provide a unique alternative to the traditional Pd-catalyzed counterpart. However, many details regarding the actual mechanism remain unknown. A series of macrocyclic iron(III) complexes were used to evaluate specifics related to the role of O 2 , radicals, and μ-oxodiiron-complex participation in the catalytic cycle. It was determined that the mononuclear tetra-azamacrocyclic complex is a true catalyst and not a stoichiometric reagent, while more than one equivalent of a sacrificial oxidant is needed. Furthermore, the reaction does not proceed through an organic radical pathway. μ-Oxodiiron complexes are not involved in the main catalytic pathway, and the dimers are, in fact, off-cycle species that decrease catalytic efficiency.

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Section: Methodsmentioning

confidence: 99%

Mechanistic Insights into Iron-Catalyzed C–H Bond Activation and C–C Coupling

et al. 2021

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“…The graphical representation of the catalytic cycle was generated using the catalytic cycle generator. 42 , 43…”

Section: Resultsmentioning

confidence: 99%

Bulky Di(1-adamantyl)phosphinous Acid-Ligated Pd(II) Precatalysts for Suzuki Reactions of Unreactive Aryl Chlorides

et al. 2021

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Di(1-adamantyl)phosphine oxide (SPO-Ad: Ad 2 P(V)(=O)H), a stable tautomer of di(1-adamantyl)phosphinous acid (PA-Ad: Ad 2 P(III)-OH), was employed to synthesize two new PA-Ad-coordinated complexes, POPd-Ad and POPd2-Ad. POPd-Ad was easily transformed from POPd2-Ad in acetonitrile, and the [M – H] − ion of the deprotonated POPd-Ad was observed in the electrospray ionization-mass spectrum of POPd2-Ad. Both complexes are effective precatalysts for the Suzuki reaction of aryl chlorides. The reduction of Pd(II) in POPd-Ad and POPd2-Ad by arylboronic acid was examined, and the ideal Pd-to-PA ratio in the Suzuki reaction was found to be 1:1. The effect of temperature on the catalytic yields was studied to examine the possible ligation state of the active species and the dimer-to-monomer process of POPd2-Ad. Mononuclear and mono-ligated Pd species was assumed to be catalytically active. The electronic and steric effects of PA-Ad were slightly better than those reported for PA-tBu ( t Bu 2 P(III)-OH). Density functional theory calculations were performed to evaluate the formation of mono-ligated and mononuclear Pd species from POPd-Ad and POPd2-Ad. Furthermore, the reaction time and catalyst loading could be reduced for the reported POPd1-tBu precatalyst using the optimized reaction conditions for POPd-Ad. The complexes synthesized in this extensive study will complement the existing SPO-coordinated POPd series of precatalysts.

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“…The catalytic cycle was generated using catacycle.com. [36] The experimental conditions were optimized to accommodate CaCO3 (Scheme 1), and reactions were monitored in real-time at different stirring rates (60 rpm vs. 400 rpm) but otherwise under the same conditions. The differences between the reactions were subtle but real (see Figure 1), with the faster stir rate resulting in a slightly higher yield.…”

Section: Resultsmentioning

confidence: 99%

Standardized Stirring for Small Scale Surveys

Omari¹,

Paul²,

McIndoe³

2021

Preprint

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Stirring rates in heterogeneous catalytic reactions have an effect on reaction rates. When conducting small-scale surveys using a single central stir plate, reaction vessels in different positions experience slightly different levels and patterns of agitation. We probed this effect by running the same reaction 40 times, varying the stir rate (fast/slow) and the vial position using two 3D printed vial holders. We found variability of conversion (measured mass spectrometrically) to be approximately two times higher for vials placed at different distances, but the effect was relatively small and could be minimized by using a high stir rate. For those experimenters wishing to completely eliminate differential stirring as a cause for variation in results, the 3D printed circular array we designed is recommended over a conventional rectangular array.

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An Information-Rich Graphical Representation of Catalytic Cycles

Cited by 10 publications

References 14 publications

Mechanistic Insights into Iron-Catalyzed C–H Bond Activation and C–C Coupling

Mechanistic Insights into Iron-Catalyzed C–H Bond Activation and C–C Coupling

Bulky Di(1-adamantyl)phosphinous Acid-Ligated Pd(II) Precatalysts for Suzuki Reactions of Unreactive Aryl Chlorides

Standardized Stirring for Small Scale Surveys

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