all-trans-2,4,6,8,10,12,14-Hexadecaheptaene | 64495-99-4

• 分子结构分类: 有机化合物 - 碳氢化合物 - 不饱和烃
• 英文名称: all-trans-2,4,6,8,10,12,14-Hexadecaheptaene
• 英文别名: 2,4,6,8,10,12,14-hexadecaheptaene；Hexadecaheptaene；(2E,4E,6E,8E,10E,12E,14E)-hexadeca-2,4,6,8,10,12,14-heptaene
• CAS: 64495-99-4
• 化学式: C₁₆H₂₀
• 分子量: 212.335
• InChiKey: HVNWKSDAXRCBJC-OPOHTQKZSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  6
• 重原子数：
  16
• 可旋转键数：
  6
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.12
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  0

反应信息

• 作为产物：
  描述：

  (2E,4E,6E,8E,10E)-dodeca-2,4,6,8,10-pentaenal 以 四氢呋喃 为溶剂， 反应 1.0h， 生成 all-trans-2,4,6,8,10,12,14-Hexadecaheptaene
  参考文献：
  名称：

  Symmetry Control of Radiative Decay in Linear Polyenes:  Low Barriers for Isomerization in the S₁ State of Hexadecaheptaene

  摘要：

  The room temperature absorption and emission spectra of the 4-cis and all-trans isomers of 2,4,6,8,10,12,14-hexadecaheptaene are almost identical, exhibiting the characteristic dual emissions S-1 -> S-0 (2(1)A(g)(-) -> 1(1)A(g)(-)) and S-2 -> S-0 (1(1)B(u)(+) -> 1(1)A(g)(-)) noted in previous studies of intermediate length polyenes and carotenoids. The ratio of the S-1 -> S-0 and S-2 -> S-0 emission yields for the cis isomer increases by a factor of similar to 15 upon cooling to 77 K in n-pentadecane. In contrast, for the trans isomer this ratio shows a 2-fold decrease with decreasing temperature. These results suggest a low barrier for conversion between the 4-cis and all-trans isomers in the S-1 state. At 77 K, the cis isomer cannot convert to the more stable all-trans isomer in the 2(1)A(g)(-) state, resulting in the striking increase in its S-1 -> S-0 fluorescence. These experiments imply that the S-1 states of longer polyenes have local energy minima, corresponding to a range of conformations and isomers, separated by relatively low (2-4 kcal) barriers. Steady state and time-resolved optical measurements on the S-1 states in solution thus may sample a distribution of conformers and geometric isomers, even for samples represented by a single, dominant ground state structure. Complex S-1 potential energy surfaces may help explain the complicated S-2 -> S-1 relaxation kinetics of many carotenoids. The finding that fluorescence from linear polyenes is so strongly dependent on molecular symmetry requires a reevaluation of the literature on the radiative properties of all-trans polyenes and carotenoids.

  DOI：

  10.1021/ja0609607

文献信息

• Oxidative doping of intermediate length polyenes: attempted oligomeric modelling of doped polyethyne
  作者：Charles W. Spangler、Roger A. Rathunde

  DOI：10.1039/c39890000026

  日期：——

  Polyenes containing 7, 8, 9, and 10 conjugated double bonds form stabilized bipolarons upon oxidative doping with antimony pentachloride, whose spectra may be useful in modelling optical changes which occur during the polyethyne doping process.

  含有7、8、9和10个共轭双键的多烯经五氯化锑氧化掺杂后可形成稳定的双极化子，其光谱可用于模拟在乙炔掺杂过程中发生的光学变化。
• Electronic relaxation in long polyenes
  作者：Sarah A. Cosgrove、Melissa A. Guite、Timothy B. Burnell、Ronald L. Christensen

  DOI：10.1021/j100384a026

  日期：1990.10
• Symmetry Control of Radiative Decay in Linear Polyenes:  Low Barriers for Isomerization in the S₁ State of Hexadecaheptaene
  作者：Ronald L. Christensen、Mary Grace I. Galinato、Emily F. Chu、Ritsuko Fujii、Hideki Hashimoto、Harry A. Frank

  DOI：10.1021/ja0609607

  日期：2007.2.1

  The room temperature absorption and emission spectra of the 4-cis and all-trans isomers of 2,4,6,8,10,12,14-hexadecaheptaene are almost identical, exhibiting the characteristic dual emissions S-1 -> S-0 (2(1)A(g)(-) -> 1(1)A(g)(-)) and S-2 -> S-0 (1(1)B(u)(+) -> 1(1)A(g)(-)) noted in previous studies of intermediate length polyenes and carotenoids. The ratio of the S-1 -> S-0 and S-2 -> S-0 emission yields for the cis isomer increases by a factor of similar to 15 upon cooling to 77 K in n-pentadecane. In contrast, for the trans isomer this ratio shows a 2-fold decrease with decreasing temperature. These results suggest a low barrier for conversion between the 4-cis and all-trans isomers in the S-1 state. At 77 K, the cis isomer cannot convert to the more stable all-trans isomer in the 2(1)A(g)(-) state, resulting in the striking increase in its S-1 -> S-0 fluorescence. These experiments imply that the S-1 states of longer polyenes have local energy minima, corresponding to a range of conformations and isomers, separated by relatively low (2-4 kcal) barriers. Steady state and time-resolved optical measurements on the S-1 states in solution thus may sample a distribution of conformers and geometric isomers, even for samples represented by a single, dominant ground state structure. Complex S-1 potential energy surfaces may help explain the complicated S-2 -> S-1 relaxation kinetics of many carotenoids. The finding that fluorescence from linear polyenes is so strongly dependent on molecular symmetry requires a reevaluation of the literature on the radiative properties of all-trans polyenes and carotenoids.