Copper(I) bromide (CuBr)
"baseclick-grade" copper catalyst in high quality for optimal yield
| Size | Catalog No. | Price |
|---|---|---|
| 5 x 5 mg | BCMI-001-5x5 | € 80,00 |
| 10 x 5 mg | BCMI-001-5x10 | € 135,00 |
Chemical Properties
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Molecular Formula
CuBr
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Shelf Life
12 months unopened after receipt
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Storage Conditions
RT, dry and under inert gas
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Molecular Weight
143.45 g/mol
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Purity
≥ 99% (trace metal analysis)
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Physical State
pale green powder
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CAS Number
7787-70-4
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Solubility
Click Solution (BCMI-003)
Product Information
High-Purity Catalyst for CuAAC Click Chemistry
Copper(I) bromide (CuBr) is one of the potential copper sources for catalyzing alkyne-azide cycloaddition (CuAAC) reactions. The CuAAC reaction was the first descript reaction to meet the criteria for “Click Chemistry” and remains the most widely used click reaction to date.
CuBr is soluble in organic solvents, making it the preferred catalyst for click reactions involving hydrolysis-sensitive compounds. For aqueous systems, CuSO4 or heterogenous copper catalyst are typically used due to CuBr’s limited water solubility.
Unlike Cu(II) sulfate, which requires in situ reduction, CuBr provides the catalytically active Cu(I) species directly, eliminating the need for activation steps.
Challenges & Solutions
Cu(I) species are highly sensitive to oxidation by atmospheric oxygen, which can rapidly degrade catalytic activity. To ensure maximum efficiency:
- baseclick handles its high-purity CuBr entirely under argon to prevent premature oxidation.
- We recommend using degassed solutions under an inert atmosphere for optimal results.
However, our experiments show that quantitative yields are achievable without inert conditions if the dissolved catalyst is used immediately (within 30 minutes of preparation).
To prevent side reactions, always use a copper-chelating ligand such as TBTA, which is soluble in organic environments and stabilizes Cu(I).
Click Solution for Optimal Performance
Our experiments confirmed that a solvent mixture called click solution, a mixture of DMSO and t-BuOH is ideal for CuAAC reactions using CuBr.
Protocol Support
To help optimize the performance of your reactions, baseclick provides a protocol for the setup of CuAAC reactions with CuBr. Please be aware that this protocol is only meant as a starting point. For different concentrations or reaction partners, as mentioned in the protocol, please consider adjusting the conditions to achieve the best possible outcome.
FAQ
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My CuBr-click solution turns brownish. Can I still use it?
CuBr should result in a yellow-greenish to green clear solution upon dissolving. If your catalyst turns brownish upon addition of the click solution it is most likely degraded (oxidized). Please use a fresh batch of CuBr to ensure optimal click reaction catalysis.
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What is the best catalyst for my reaction?
The optimal catalyst depends on your application and the solvents used. In general, there are three major catalyst systems for copper-catalyzed click reactions that apply the required Cu(I) source:
1) Working in aqueous media: Then we recommend using a CuSO4 (BCMI-004) based system. To generate the catalytic Cu(I) species, please do not forget to add the necessary sodium ascorbate (BCMI-005) and our water soluble THPTA ligand (BCMI-006). As the sodium ascorbate has restricted stability when dissolved, please prepare this solution always fresh.
2) Working in organic medium (mostly DMSO or click solution): Then we recommend using CuBr and TBTA ligand (BCMI-002) for labeling reactions. Please note, that CuBr is sensitive to air. Therefore, we take precautions when aliquoting and sealing this compound. Once opened, please use the compound fast (within a few hours maximum).
3) For small sample amounts from e.g. enzymatic reactions in aqueous media we recommend using our reactor system that is part of our Oligo Link kits. As this catalyst will not dissolve during the reaction and can also be applied in organic media, its handling is very simple as described in the kit user manual. Additionally, the long-term storage is superior compared to the other catalyst systems. -
What is the yield of click reactions?
The nature of click chemistry is that the reactions are fast, efficient and results in high yields. Under optimal conditions, quantitative yields are easily achieved.
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Which reagents to avoid in copper catalyzed click reactions?
Some biochemical buffer components can interfere with the copper-catalyzed click reactions (CuAAC). For example, TE and TAE buffer contain EDTA which chelates the copper ions and thus decreases reaction kinetic and yield. Moreover, free thiols, as dithiothreitol (DTT) and mercapto ethanol, can deteriorate or completely prevent click reactions.
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What kind of labels can be clicked?
As it is the nature of click reactions, various groups can be attached to nucleic acids, not constricted to dyes. The only requirement is the use of high quality reagents containing clickable groups.
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Why use CuBr for CuAAC instead of CuSO₄?
CuBr is unlike CuSO4 soluble in organic solvents and should therefore be used if CuAAC is performed in non-aqueous solvent systems. CuBr providing the catalytically active Cu(I) species directly, eliminating the need for in situ Cu(II) reduction, is an additional benefit.
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When should I choose CuBr over other copper sources?
CuBr is ideal for click reactions involving hydrolysis-sensitive compounds in organic solvents. For aqueous systems, CuSO₄ or heterogeneous copper catalysts are preferred due to the limited solubility of CuBr in aqueous solution.
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How do I prevent CuBr from oxidizing?
Cu(I) is highly sensitive to oxygen. Use degassed solutions under an inert atmosphere (argon) for best results. If inert conditions are not possible, use the catalyst immediately after dissolution (within 30 minutes).
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Do I need a ligand with CuBr?
Yes. A copper-chelating ligand such as TBTA is recommended to stabilize Cu(I) and prevent side reactions. TBTA is soluble in organic environments and works perfectly with CuBr.
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What is Click Solution and why should I use it?
Click Solution is a proprietary mixture of DMSO and tert-butanol developed by baseclick to dissolve CuBr efficiently and maintain its catalytic integrity during CuAAC reactions.
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Does baseclick provide protocols for CuBr click reactions?
Yes. We offer a standard protocol for CuBr-based CuAAC using Click Solution, which can be adapted to your specific reactants and concentrations.