chloro(pentamethylcyclopentadienyl)(cyclopentadienyl)(2,2,6,6-tetramethylpiperidine-N-oxyl)titanium | 850415-43-9

• 英文名称: chloro(pentamethylcyclopentadienyl)(cyclopentadienyl)(2,2,6,6-tetramethylpiperidine-N-oxyl)titanium
• CAS: 850415-43-9
• 化学式: C₂₄H₃₈ClNOTi
• 分子量: 439.905
• InChiKey: JVGIEAYALGNPPH-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  None
• 重原子数：
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• 可旋转键数：
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• 环数：
  None
• sp3杂化的碳原子比例：
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• 拓扑面积：
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• 氢给体数：
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• 氢受体数：
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反应信息

• 作为反应物：
  描述：

  4-甲氧基-四甲基哌啶氧自由基 、 chloro(pentamethylcyclopentadienyl)(cyclopentadienyl)(2,2,6,6-tetramethylpiperidine-N-oxyl)titanium 以 氘代苯 为溶剂， 生成 chloro(pentamethylcyclopentadienyl)(cyclopentadienyl)(2,2,6,6-tetramethyl-4-methoxypiperidine-N-oxyl)titanium
  参考文献：
  名称：

  Homolysis of Weak Ti−O Bonds:  Experimental and Theoretical Studies of Titanium Oxygen Bonds Derived from Stable Nitroxyl Radicals

  摘要：

  Titanium-oxygen bonds derived from stable nitroxyl radicals are remarkably weak and can be homolyzed at 60 degrees C. The strength of these bonds depends sensitively on the ancillary ligation at titanium. Direct measurements of the rate of Ti-O bond homolysis in Ti-TEMPO complexes CP2TiCl(TEMPO) (3) and Cp2TiCl(4-MeO-TEMPO) (4) (TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl, 4-MeO-TEMPO = 2,2,6,6-tetramethyl-4-methoxypiperidine-N-oxyl) were conducted by nitroxyl radical exchange experiments. Eyring plots gave the activation parameters, Delta H-double dagger = 27(+/- 1) kcal/mol, Delta S-double dagger = 6.9(+/- 2.3) eu for 3 and Delta H-double dagger = 28(+/- 1) kcal/mol, Delta S-double dagger = 9.0(+/- 3.0) eu for 4, consistent with a process involving the homolysis of a weak Ti-O bond to generate the transient Cp2Ti(III)Cl and the nitroxyl radical. Thermolysis of the titanocene TEMPO complexes in the presence of epoxides leads to the Cp2Ti(III)Cl-mediated ring-opening of the epoxide followed by trapping by the nitroxyl radical. The X-ray crystal structure of the Ti-TEMPO derivative, Cp2TiCl(4-MeO-TEMPO) (4), is reported. DFT (B3LYP/6-31G*) calculations and experimental studies reveal that the strength of the Ti-O bond decreases dramatically with the number of cyclopentadienyl groups on titanium. The calculated Ti-O bond strength of the monocyclopentadienyl complex 2 is 43 kcal/mol, whereas that of the biscyclopentadienyl complex 3 is 17 kcal/mol, a difference of 26 kcal/mol. These studies reveal that the strength of these Ti-O bonds can be tuned over an interesting and experimentally accessible temperature range by appropriate ligation on titanium.

  DOI：

  10.1021/ja044512f
• 作为产物：
  描述：

  2,2,6,6-四甲基哌啶氧化物 、 [TiCp(C₅Me₅)Cl₂] 在 Zn 作用下， 以 四氢呋喃 为溶剂， 以31.9%的产率得到chloro(pentamethylcyclopentadienyl)(cyclopentadienyl)(2,2,6,6-tetramethylpiperidine-N-oxyl)titanium
  参考文献：
  名称：

  Homolysis of Weak Ti−O Bonds:  Experimental and Theoretical Studies of Titanium Oxygen Bonds Derived from Stable Nitroxyl Radicals

  摘要：

  Titanium-oxygen bonds derived from stable nitroxyl radicals are remarkably weak and can be homolyzed at 60 degrees C. The strength of these bonds depends sensitively on the ancillary ligation at titanium. Direct measurements of the rate of Ti-O bond homolysis in Ti-TEMPO complexes CP2TiCl(TEMPO) (3) and Cp2TiCl(4-MeO-TEMPO) (4) (TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl, 4-MeO-TEMPO = 2,2,6,6-tetramethyl-4-methoxypiperidine-N-oxyl) were conducted by nitroxyl radical exchange experiments. Eyring plots gave the activation parameters, Delta H-double dagger = 27(+/- 1) kcal/mol, Delta S-double dagger = 6.9(+/- 2.3) eu for 3 and Delta H-double dagger = 28(+/- 1) kcal/mol, Delta S-double dagger = 9.0(+/- 3.0) eu for 4, consistent with a process involving the homolysis of a weak Ti-O bond to generate the transient Cp2Ti(III)Cl and the nitroxyl radical. Thermolysis of the titanocene TEMPO complexes in the presence of epoxides leads to the Cp2Ti(III)Cl-mediated ring-opening of the epoxide followed by trapping by the nitroxyl radical. The X-ray crystal structure of the Ti-TEMPO derivative, Cp2TiCl(4-MeO-TEMPO) (4), is reported. DFT (B3LYP/6-31G*) calculations and experimental studies reveal that the strength of the Ti-O bond decreases dramatically with the number of cyclopentadienyl groups on titanium. The calculated Ti-O bond strength of the monocyclopentadienyl complex 2 is 43 kcal/mol, whereas that of the biscyclopentadienyl complex 3 is 17 kcal/mol, a difference of 26 kcal/mol. These studies reveal that the strength of these Ti-O bonds can be tuned over an interesting and experimentally accessible temperature range by appropriate ligation on titanium.

  DOI：

  10.1021/ja044512f