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34 results on '"Noonikara-Poyil, Anurag"'

11. Binding Interactions in Copper, Silver and Gold pi-Complexes

Author

Mehara, J.M., Watson, Brandon T., Noonikara-Poyil, Anurag, Zacharias, Adway O., Roithova, J., Rasika Dias, H.V., Mehara, J.M., Watson, Brandon T., Noonikara-Poyil, Anurag, Zacharias, Adway O., Roithova, J., and Rasika Dias, H.V.

Abstract

11 maart 2022, Contains fulltext : 247530.pdf (Publisher’s version ) (Open Access)

Published
2022

31. Terminal and Internal Alkyne Complexes and Azide-Alkyne Cycloaddition Chemistry of Copper(I) Supported by a Fluorinated Bis(pyrazolyl)borate.

Author

Noonikara-Poyil, Anurag, Muñoz-Castro, Alvaro, and Dias, H. V. Rasika

Subjects
*COPPER, *BORATES, *COPPER catalysts, *COORDINATE covalent bond, *ORBITAL interaction, *RING formation (Chemistry), *CATALYSTS
Abstract

Copper plays an important role in alkyne coordination chemistry and transformations. This report describes the isolation and full characterization of a thermally stable, copper(I) acetylene complex using a highly fluorinated bis(pyrazolyl)borate ligand support. Details of the related copper(I) complex of HC≡CSiMe3 are also reported. They are three-coordinate copper complexes featuring η2-bound alkynes. Raman data show significant red-shifts in C≡C stretch of [H2B(3,5-(CF3)2Pz)2]Cu(HC≡CH) and [H2B(3,5-(CF3)2Pz)2]Cu(HC≡CSiMe3) relative to those of the corresponding alkynes. Computational analysis using DFT indicates that the Cu(I) alkyne interaction in these molecules is primarily of the electrostatic character. The π-backbonding is the larger component of the orbital contribution to the interaction. The dinuclear complexes such as Cu2(μ-[3,5-(CF3)2Pz])2(HC≡CH)2 display similar Cu-alkyne bonding features. The mononuclear [H2B(3,5-(CF3)2Pz)2]Cu(NCMe) complex catalyzes [3 + 2] cycloadditions between tolyl azide and a variety of alkynes including acetylene. It is comparatively less effective than the related trinuclear copper catalyst {μ-[3,5-(CF3)2Pz]Cu}3 involving bridging pyrazolates. [ABSTRACT FROM AUTHOR]

Published
2022
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33. When SF 5 outplays CF 3 : effects of pentafluorosulfanyl decorated scorpionates on copper.

Author

Noonikara-Poyil A, Muñoz-Castro A, Boretskyi A, Mykhailiuk PK, and Dias HVR

Abstract

Polyfluorinated, electron-withdrawing, and sterically demanding supporting ligands are of significant value in chemistry. Here we report the assembly and use of a bis(pyrazolyl)borate, [Ph 2 B(3-(SF 5 )Pz) 2 ] - that combines all such features, and involves underutilized pentafluorosulfanyl substituents. The ethylene and carbonyl chemistry of copper(i) supported by [Ph 2 B(3-(SF 5 )Pz) 2 ] - , a comparison to the trifluoromethylated counterparts involving [Ph 2 B(3-(CF 3 )Pz) 2 ] - , as well as copper catalyzed cyclopropanation of styrene with ethyl diazoacetate and CF 3 CHN 2 are presented. The results from cyclopropanation show that SF 5 groups dramatically improved the yields and stereoselectivity compared to the CF 3 ., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Published
2021
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34. Isolable Copper(I) η 2 -Cyclopropene Complexes.

Author

Noonikara-Poyil A, Ridlen SG, and Dias HVR

Abstract

Treatment of bis(pyrazolyl)borate ligand supported [(CF 3 ) 2 Bp]Cu(NCMe) with 1,2,3-trisubstituted cyclopropenes produced thermally stable copper(I) η 2 -cyclopropene complexes amenable to detailed solution and solid-state analysis. The [(CF 3 ) 2 Bp]Cu(NCMe) also catalyzed [2 + 1]-cycloaddition chemistry of terminal and internal alkynes with ethyl diazoacetate affording cyclopropenes, including those used as ligands in this work. The tris(pyrazolyl)borate [(CF 3 ) 2 Tp]Cu(NCMe) is a competent catalyst for this process as well. The treatment of [(CF 3 ) 2 Tp]Cu with ethyl 2,3-diethylcycloprop-2-enecarboxylate substrate gave an O-bonded rather than a η 2 -cyclopropene copper complex.

Published
2020
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