Isolation of an acetylide-CuI3-tris(triazolylmethyl)amine complex active in the CuAAC reaction

[Display omitted] •The structure of tris(triazolylmethyl)amine-stabilized CuI3–acetylide is reported.•The structural factors for stabilizing the CuI3–acetylide complex are analyzed.•The trinuclear complex could enhance the CuAAC reaction by promoting azide binding.•Upon azide binding, Cu dissociatio...

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Bibliographic Details
Published in:Journal of catalysis 2018-05, Vol.361, p.407-413
Main Authors: Chen, Haoqing, Soubra-Ghaoui, Chirine, Zhu, Zhiling, Li, Siheng, Albright, Thomas A., Cai, Chengzhi
Format: Article
Language:English
Subjects:
Click chemistry
CuAAC reaction
Intermediate
Mechanism
X-rays
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Summary:[Display omitted] •The structure of tris(triazolylmethyl)amine-stabilized CuI3–acetylide is reported.•The structural factors for stabilizing the CuI3–acetylide complex are analyzed.•The trinuclear complex could enhance the CuAAC reaction by promoting azide binding.•Upon azide binding, Cu dissociation gives rise to the more favorable Cu2 transition state. The CuAAC click reaction is greatly accelerated by tris(triazolylmethyl)amine ligands (TL). Using mass spectrometry, we found a trinuclear TL–CuI3–acetylide complex formed in the reaction. Under catalytic conditions, the trinuclear complex is more active than the proposed dinuclear complex, whereas in a single-turnover reaction, the dinuclear complex is more reactive. Here, this finding is rationalized by analysis of the first single-crystal X-ray structure of a trinuclear TL–CuI3–acetylide complex and DFT calculation, revealing how TL stabilizes the trinuclear complex, which may accelerate the reaction by promoting coordination with an azide followed by dissociation of a CuI to form a more favorable dinuclear transition state.
ISSN:0021-9517
1090-2694
DOI:10.1016/j.jcat.2018.02.024