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Your search keyword '"Carroll, Patrick"' showing total 28 results
Start Over Author "Carroll, Patrick" Journal angewandte chemie
28 results on '"Carroll, Patrick"'

1. Metallacyclobuta‐(2,3)‐diene: A Bidentate Ligand for Stream‐line Synthesis of First Row Transition Metal Catalysts for Cyclic Polymerization of Phenylacetylene.

Author

Russell, John B., Konar, Debabrata, Keller, Taylor M., Gau, Michael R., Carroll, Patrick J., Telser, Joshua, Lester, Daniel W., Veige, Adam S., Sumerlin, Brent S., and Mindiola, Daniel J.

Subjects
TRANSITION metal catalysts, ETHYNYL benzene, INTRINSIC viscosity, POLYMERS, POLYMERIZATION, NITROUS oxide
Abstract

Described here is a direct entry to two examples of 3d transition metal catalysts that are active for the cyclic polymerization of phenylacetylene, namely, [(BDI)M{κ2‐C,C‐(Me3SiC3SiMe3)}] (2‐M) (BDI=[ArNC(CH3)]2CH−, Ar=2,6‐iPr2C6H3; M=Ti, V). Catalysts are prepared in one step by the treatment of [(BDI)MCl2] (1‐M, M=Ti, V) with 1,3‐dilithioallene [Li2(Me3SiC3SiMe3)]. Complexes 2‐M have been spectroscopically and structurally characterized and the polymers that are catalytically formed from phenylacetylene were verified to have a cyclic topology based on a combination of size‐exclusion chromatography (SEC) and intrinsic viscosity studies. Two‐electron oxidation of 2‐V with nitrous oxide (N2O) cleanly yields a [VV] alkylidene‐alkynyl oxo complex [(BDI)V(=O){κ1‐C‐(=C(SiMe3)CC(SiMe3))}] (3), which lends support for how this scaffold in 2‐M might be operating in the polymerization of the terminal alkyne. This work demonstrates how alkylidynes can be circumvented using 1,3‐dianionic allene as a segue into M−C multiple bonds. [ABSTRACT FROM AUTHOR]

Published
2024
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3. Iron‐Catalyzed Intermolecular C−H Amination Assisted by an Isolated Iron‐Imido Radical Intermediate.

Author

Zars, Ethan, Pick, Lisa, Swain, Abinash, Bhunia, Mrinal, Carroll, Patrick J., Munz, Dominik, Meyer, Karsten, and Mindiola, Daniel J.

Subjects
AMINATION, RADICALS (Chemistry), XANTHENE derivatives, CYCLOHEXADIENE, METHYL groups, METAL complexes, TRICHLOROPHENOL, AZIDATION
Abstract

Here we report the use of a base metal complex [(tBupyrpyrr2)Fe(OEt2)] (1‐OEt2) (tBupyrpyrr22−=3,5‐tBu2‐bis(pyrrolyl)pyridine) as a catalyst for intermolecular amination of Csp3−H bonds of 9,10‐dihydroanthracene (2 a) using 2,4,6‐trimethyl phenyl azide (3 a) as the nitrene source. The reaction is complete within one hour at 80 °C using as low as 2 mol % 1‐OEt2 with control in selectivity for single C−H amination versus double C−H amination. Catalytic C−H amination reactions can be extended to other substrates such as cyclohexadiene and xanthene derivatives and can tolerate a variety of aryl azides having methyl groups in both ortho positions. Under stoichiometric conditions the imido radical species [(tBupyrpyrr2)Fe{=N(2,6‐Me2‐4‐tBu‐C6H2)] (1‐imido) can be isolated in 56 % yield, and spectroscopic, magnetometric, and computational studies confirmed it to be an S = 1 FeIV complex. Complex 1‐imido reacts with 2 a to produce the ferrous aniline adduct [(tBupyrpyrr2)Fe{NH(2,6‐Me2‐4‐tBu‐C6H2)(C14H11)}] (1‐aniline) in 45 % yield. Lastly, it was found that complexes 1‐imido and 1‐aniline are both competent intermediates in catalytic intermolecular C−H amination. [ABSTRACT FROM AUTHOR]

Published
2023
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5. Phosphorus‐Atom Transfer from Phosphaethynolate to an Alkylidyne

Author

Jafari, Mehrafshan G., primary, Park, Yerin, additional, Pudasaini, Bimal, additional, Kurogi, Takashi, additional, Carroll, Patrick J., additional, Kaphan, David M., additional, Kropf, Jeremy, additional, Delferro, Massimiliano, additional, Baik, Mu‐Hyun, additional, and Mindiola, Daniel J., additional

Published
2021
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6. N−H Bond Formation at a Diiron Bridging Nitride

Author

Zhang, Shaoguang, primary, Cui, Peng, additional, Liu, Tianchang, additional, Wang, Qiuran, additional, Longo, Thomas J., additional, Thierer, Laura M., additional, Manor, Brian C., additional, Gau, Michael R., additional, Carroll, Patrick J., additional, Papaefthymiou, Georgia C., additional, and Tomson, Neil C., additional

Published
2020
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8. Magnetic Field Directed Rare‐Earth Separations.

Author

Higgins, Robert F., Cheisson, Thibault, Cole, Bren E., Manor, Brian C., Carroll, Patrick J., and Schelter, Eric J.

Subjects
MAGNETIC fields, RARE earth metals, ION bombardment, MAGNETICS, MAGNETIC properties, BINARY mixtures, RARE earth ions
Abstract

The separation of rare‐earth ions from one another is challenging due to their chemical and physical similarities. Nearly all rare‐earth separations rely upon small changes in ionic radii to direct speciation or reactivity. Herein, we show that the intrinsic magnetic properties of the rare‐earth ions impact the separations of light/heavy and selected heavy/heavy binary mixtures. Using TriNOx3− ([{(2‐tBuNO)C6H4CH2}3N]3−) rare‐earth complexes, we efficiently and selectively crystallized heavy rare earths (Tb–Yb) from a mixture with light rare earths (La and Nd) in the presence of an external Fe14Nd2B magnet, concomitant with the introduction of a concentration gradient (decrease in temperature). The optimal separation was observed for an equimolar mixture of La:Dy, which gave an enrichment factor of EFLa:Dy=297±31 for the solid fraction, compared to EFLa:Dy=159±22 in the absence of the field, and achieving a 99.7 % pure Dy sample in one step. These results indicate that the application of a magnetic field can improve performance in a molecular separation system for paramagnetic rare‐earth cations. [ABSTRACT FROM AUTHOR]

Published
2020
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