Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemistry and Chemical Biology. The Baruch ’60 Center for Biochemical Solar Energy Research
Here, a discrete, dicopper μ-alkynyl complex, [Cu2(μ-η1:η1-C≡C(C6H4)CH3)DPFN]NTf2 (DPFN = 2,7-bis(fluoro-di(2-pyridyl)methyl)-1,8-naphthyridine; NTf2– = N(SO2CF3)2–), reacts with p-tolylazide to yield a dicopper complex with a symmetrically bridging 1,2,3-triazolide, [Cu2(μ-η1:η1-(1,4-bis(4-tolyl)-1,2,3-triazolide))DPFN]NTf2. This transformation exhibits bimolecular reaction kinetics and represents a key step in a proposed, bimetallic mechanism for copper-catalyzed azide–alkyne cycloaddition (CuAAC). The μ-alkynyl and μ-triazolide complexes undergo reversible redox events (by cyclic voltammetry), suggesting that a cycloaddition pathway involving mixed-valence dicopper species might also be possible. Synthesis and characterization of the mixed-valence μ-alkynyl dicopper complex, [Cu2(μ-η1:η1-C≡C(C6H4)CH3)DPFN](NTf2)2, revealed an electronic structure with an unexpected partially delocalized spin, as evidenced by electron paramagnetic resonance spectroscopy. Finally, studies of the mixed-valence μ-alkynyl complex’s reactivity suggest that a mixed-valence pathway is less likely than one involving intermediates with only copper(I).
Ziegler, Micah S., et al. "Dicopper Cu(I)Cu(I) and Cu(I)Cu(II) Complexes in Copper-Catalyzed Azide–Alkyne Cycloaddition." Journal of the American Chemical Society, vol. 139, no. 15, Apr. 2017. https://doi.org/10.1021/jacs.6b13261
Ziegler, Micah S., Lakshmi, K. V., & Tilley, T. Don (2017). Dicopper Cu(I)Cu(I) and Cu(I)Cu(II) Complexes in Copper-Catalyzed Azide–Alkyne Cycloaddition. Journal of the American Chemical Society, 139(15). https://doi.org/10.1021/jacs.6b13261
Ziegler, Micah S., Lakshmi, K. V., and Tilley, T. Don, "Dicopper Cu(I)Cu(I) and Cu(I)Cu(II) Complexes in Copper-Catalyzed Azide–Alkyne Cycloaddition," Journal of the American Chemical Society 139, no. 15 (2017), https://doi.org/10.1021/jacs.6b13261
@article{osti_1476482,
author = {Ziegler, Micah S. and Lakshmi, K. V. and Tilley, T. Don},
title = {Dicopper Cu(I)Cu(I) and Cu(I)Cu(II) Complexes in Copper-Catalyzed Azide–Alkyne Cycloaddition},
annote = {Here, a discrete, dicopper μ-alkynyl complex, [Cu2(μ-η1:η1-C≡C(C6H4)CH3)DPFN]NTf2 (DPFN = 2,7-bis(fluoro-di(2-pyridyl)methyl)-1,8-naphthyridine; NTf2– = N(SO2CF3)2–), reacts with p-tolylazide to yield a dicopper complex with a symmetrically bridging 1,2,3-triazolide, [Cu2(μ-η1:η1-(1,4-bis(4-tolyl)-1,2,3-triazolide))DPFN]NTf2. This transformation exhibits bimolecular reaction kinetics and represents a key step in a proposed, bimetallic mechanism for copper-catalyzed azide–alkyne cycloaddition (CuAAC). The μ-alkynyl and μ-triazolide complexes undergo reversible redox events (by cyclic voltammetry), suggesting that a cycloaddition pathway involving mixed-valence dicopper species might also be possible. Synthesis and characterization of the mixed-valence μ-alkynyl dicopper complex, [Cu2(μ-η1:η1-C≡C(C6H4)CH3)DPFN](NTf2)2, revealed an electronic structure with an unexpected partially delocalized spin, as evidenced by electron paramagnetic resonance spectroscopy. Finally, studies of the mixed-valence μ-alkynyl complex’s reactivity suggest that a mixed-valence pathway is less likely than one involving intermediates with only copper(I).},
doi = {10.1021/jacs.6b13261},
url = {https://www.osti.gov/biblio/1476482},
journal = {Journal of the American Chemical Society},
issn = {ISSN 0002-7863},
number = {15},
volume = {139},
place = {United States},
publisher = {American Chemical Society (ACS)},
year = {2017},
month = {04}}
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
National Inst. of Health (NIH) (United States); National Science Foundation (NSF) (United States); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
AC02-05CH11231; FG02-07ER15903; SC0004993
OSTI ID:
1476482
Journal Information:
Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 15 Vol. 139; ISSN 0002-7863