TEMPO

• CAS: 2564-83-2
• Catalog Number: ACM2564832-4
• Category: Inhibitors
• Molecular Weight: 156.25
• Molecular Formula: C9H18NO
• Description: (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl or (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl, commonly known as TEMPO, is a chemical compound with the formula (CH2)3(CMe2)2NO. This heterocyclic compound is a red-orange, sublimable solid. As a stable radical, it has applications in chemistry and biochemistry. TEMPO was discovered by Lebedev and Kazarnowskii in 1960. It is prepared by oxidation of 2,2,6,6-tetramethylpiperidine. TEMPO is widely used as a radical marker, as a structural probe for biological systems in conjunction with electron spin resonance spectroscopy, as a reagent in organic synthesis, and as a mediator in controlled radical polymerization. The stability of this radical is attributed to the resonance provided by non-bonding electrons on the nitrogen atom, which form a 2c3e (half-) bond between nitrogen and oxygen, and hyperconjugative ability. Additional stability arises from the steric protection provided by the four methyl groups adjacent to the nitroxyl group; however, the methyl groups prevent a double bond occurring between either carbon adjacent to nitrogen. The stability of the radical is also indicated by the weakness of the O–H bond in the hydrogenated derivative TEMPO–H. With an O–H bond dissociation energy of about 70kcal/mol, this bond is about 30% weaker than a typical O–H bond.
• Synonyms: TEMPO free radical; 2,2,6,6-Tetramethyl-1-piperidinyloxy, free radical; 2,2,6,6-Tetramethylpiperidinooxy; 2,2,6,6-Tetramethylpiperidine 1-oxyl
• Canonical SMILES: CC1(CCCC(N1[O])(C)C)C
• InChI: InChI=1S/C9H18NO/c1-8(2)6-5-7-9(3,4)10(8)11/h5-7H2,1-4H3
• InChI Key: QYTDEUPAUMOIOP-UHFFFAOYSA-N
• Boiling Point: 193°C
• Melting Point: 36-40ºC
• Flash Point: 67ºC
• Density: 1 g/cm³
• Solubility: Soluble in all organic solvents. Insoluble in water.
• Appearance: Orange crystals or powder
• Application: Contact reaction oxidant for iodobenzene diacetyl to oxidize nerol to generate neral. In summary, copper/TEMPO is used for the contact reaction of the 1-alcohol to form an aldehyde.
• Storage: Store at 2-8°C, filled with argon
• Complexity: 136
• Covalently-Bonded Unit Count: 1
• Defined Atom Stereocenter Count: 0
• Defined Bond Stereocenter Count: 0
• EC Number: 219-888-8
• Exact Mass: 156.138839198
• Formal Charge: 0
• Hazard Codes: C; Xi
• Heavy Atom Count: 11
• HS Code: 29333999
• Hydrogen Bond Acceptor Count: 1
• Hydrogen Bond Donor Count: 0
• Isotope Atom Count: 0
• LogP: 2.31290
• MDL Number: MFCD00009599
• Monoisotopic Mass: 156.138839198
• Physical State: Yellow to green powder
• PSA: 3.24
• RIDADR: UN 3263
• Rotatable Bond Count: 0
• Shipping: Can be shipped at room temperature, where not in use may vary.
• Stability: Stable. Incompatible with strong acids, strong oxidizing agents. Refrigerate.
• Storage Conditions: 2-8ºC
• Topological Polar Surface Area: 4.2 Ų
• Undefined Atom Stereocenter Count: 0
• Undefined Bond Stereocenter Count: 0
• WGK Germany: 3