XPhos Pd G2 is a widely used palladium-based catalyst in organic synthesis. It is known for its high efficiency in cross-coupling reactions, particularly in Suzuki-Miyaura and Buchwald-Hartwig amination reactions. This catalyst plays a crucial role in pharmaceutical, material science, and fine chemical industries.
This topic explores the CAS number, chemical properties, synthesis, applications, and safety precautions related to XPhos Pd G2.
What Is XPhos Pd G2?
Definition and Importance
XPhos Pd G2 is a preformed palladium catalyst based on the XPhos ligand. It is a second-generation (G2) catalyst, meaning it has improved stability, solubility, and efficiency compared to earlier versions.
CAS Number of XPhos Pd G2
Every chemical compound is assigned a CAS (Chemical Abstracts Service) number, which serves as a unique identifier. The CAS number for XPhos Pd G2 ensures easy reference in chemical databases and research papers.
Chemical Properties of XPhos Pd G2
Molecular Structure
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Core Metal: Palladium (Pd)
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Ligand System: XPhos (a bulky biaryl phosphine ligand)
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Oxidation State of Pd: Typically +2
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Stability: Highly stable under reaction conditions
Physical Properties
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Appearance: Usually a solid powder or crystalline form
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Color: Yellow to brown (depending on purity)
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Solubility: Soluble in organic solvents like toluene, THF, and dichloromethane
Synthesis of XPhos Pd G2
XPhos Pd G2 is synthesized by coordinating XPhos ligand with a palladium source. The process involves:
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Ligand Coordination: The XPhos ligand is reacted with Pd(II) or Pd(0) precursors.
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Purification: The catalyst is purified using recrystallization or chromatography to ensure high purity.
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Characterization: Techniques like NMR, IR, and mass spectrometry confirm the structure and composition.
Applications of XPhos Pd G2 in Organic Synthesis
1. Suzuki-Miyaura Cross-Coupling Reactions
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Used for forming carbon-carbon (C-C) bonds between aryl or vinyl halides and boronic acids.
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Produces biaryl compounds, crucial for pharmaceuticals, agrochemicals, and materials science.
2. Buchwald-Hartwig Amination
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Catalyzes the formation of C-N bonds in amines and aryl halides.
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Essential for drug development and polymer chemistry.
3. Heck and Sonogashira Reactions
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Facilitates the formation of substituted alkenes and aryl alkynes.
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Applied in the synthesis of complex organic frameworks.
4. Industrial and Pharmaceutical Applications
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Used in the manufacturing of active pharmaceutical ingredients (APIs).
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Involved in the production of OLED materials and conductive polymers.
Advantages of XPhos Pd G2 Over Traditional Catalysts
1. High Efficiency and Selectivity
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Lower catalyst loading is required compared to older palladium catalysts.
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Produces fewer side reactions, improving product yield.
2. Greater Stability
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Resistant to air and moisture, reducing the need for anhydrous conditions.
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Long shelf life without significant degradation.
3. Compatibility with a Wide Range of Substrates
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Works well with electron-rich, electron-poor, and sterically hindered substrates.
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Enables mild reaction conditions, beneficial for sensitive molecules.
Comparison: XPhos Pd G2 vs. Other Palladium Catalysts
| Catalyst | Ligand Type | Advantages | Common Applications |
|---|---|---|---|
| XPhos Pd G2 | Bulky biaryl phosphine | High selectivity, stability | Suzuki, Buchwald-Hartwig, Heck |
| Pd(PPh₃)₄ | Triphenylphosphine | Widely available, general-purpose | Suzuki, Heck |
| Pd(OAc)₂ + Ligand | Variable ligands | Tunable reactivity | General cross-coupling |
Handling and Safety Precautions
1. Storage Conditions
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Keep in a dry, inert atmosphere (e.g., under nitrogen or argon).
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Store at room temperature away from moisture.
2. Handling Procedures
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Use gloves, lab coats, and eye protection when handling.
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Work in a well-ventilated fume hood to avoid inhalation of fine ptopics.
3. Disposal Considerations
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Catalyst waste should be disposed of as per hazardous waste regulations.
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Can be recycled or recovered for further use.
XPhos Pd G2 is a highly efficient palladium catalyst used in organic synthesis, especially in cross-coupling reactions. With its high stability, selectivity, and compatibility, it plays a crucial role in pharmaceutical and material sciences. Proper handling and storage ensure optimal performance and safety in laboratory and industrial applications.