ethynidyl | 12595-78-7

• 分子结构分类: 有机化合物 - 有机阴离子
• 英文名称: ethynidyl
• 英文别名: dicarbon anion；Ethynid-2-yl；ethyne
• CAS: 12595-78-7
• 化学式: C₂
• 分子量: 24.022
• InChiKey: XHWLRFQJZNQFGO-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.4
• 重原子数：
  2
• 可旋转键数：
  0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.0
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为产物：
  描述：

  乙炔 以 neat (no solvent, gas phase) 为溶剂， 生成 ethynidyl
  参考文献：
  名称：

  Infrared spectroscopy of carbo‐ions. IV. TheA ²Π_u–X ²Σ⁺_gelectronic transition of C⁻₂

  摘要：

  The infrared spectrum of the A 2Πu←X 2∑+g electronic transition of C−2 has been observed under high resolution and analyzed. Three bands (v′←v)=(0,0), (1,1) and (0,1) have been observed; the first two bands were observed by using the difference laser frequency system in the frequency range of 3960–3780 cm−1 and the last by using a diode laser in the frequency range of 2210–2120 cm−1. A gas mixture of 50 mTorr of acetylene and 7 Torr of He was used for the ac discharge in an air-cooled and a water-cooled multiple inlet–outlet discharge tube. The simplicity of the optimum gas mixture suggested that C−2 is produced directly by simple dissociative electron attachment of acetylene. Altogether 103 absorption lines have been observed and accurately measured. Most of them are P, Q, and R form branches of allowed F1↔F1, F2↔F2 transitions although some forbidden F1↔F2 transitions and O and S transitions have also been measured. The hot bands (1,1) and (0,1) have been observed with intensity which is less than that for the (0,0) by a factor of only 2 or 3, in spite of the fact that the Franck–Condon factors of these transitions are lower than that for the (0,0) by 2.0 and 3.2, respectively, indicating that the vibrational temperature of C−2 in the He plasma is extremely high. All observed transitions are simultaneously fit to the formula for a 2Πu←2∑+g transition. The formulation of Brown and Watson has been used for the Hamiltonian for the 2Πu state. Molecular constants for C−2 in the two electronic states have been determined from the least-squares fitting. The constants are compared with those of other species isoelectronic to C−2. A short discussion is given about the astrophysical implication of the spectrum.

  DOI：

  10.1063/1.455731

文献信息

• Stimulated Raman pumping of C2− probed via resonant two-photon detachment
  作者：Esther de Beer、Yuexing Zhao、Ivan Yourshaw、Daniel M. Neumark

  DOI：10.1016/0009-2614(95)00967-9

  日期：1995.10

  We demonstrate for the first time that stimulated Raman pumping (SRP) can be used to vibrationally excite gas-phase negative ions. Results are presented for C2−, in which stimulated Raman pumping excites a rotationally resolved transition between the ν = 0 and ν = 1 levels of the ground 2Σg+ state; this excitation is monitored by resonant two-photon detachment through the excited B 2Σu+ state. At least

  我们首次证明了受激拉曼泵浦（SRP）可用于振动激发气相负离子。结果表示对于C 2 - ，其中受激拉曼泵浦激励之间的旋转解决过渡ν = 0和ν = 1倍的水平地面2 Σ克+状态; 这种激励是通过共振双光子脱离通过激发乙监测2 Σ Ú +状态。至少35％转化为ν在这项研究中达到了1级。预期该方法是相当普遍的，并且将为研究负离子的振动光谱学提供一个极好的工具。
• An electronic absorption spectrum of carbon ion (C2+): ~B4.SIGMA.u- .rarw. ~X4.SIGMA.g-
  作者：Daniel. Forney、Hartwig. Althaus、John P. Maier

  DOI：10.1021/j100310a007

  日期：1987.12
• Photodetachment spectroscopy of C₂⁻ autodetaching resonances
  作者：P. L. Jones、R. D. Mead、B. E. Kohler、S. D. Rosner、W. C. Lineberger

  DOI：10.1063/1.440678

  日期：1980.11

  The cross section for photodetachment of C2− is investigated in the photon energy range 14 000–20 000 cm−1 (1.75–2.5 eV). Sharp resonances due to autodetachment are observed at photon energies corresponding to transitions between high vibrational levels of the C2− X 2Σg+ state and high vibrational levels of the C2− B 2Σu+ states. The resonances are narrower than 6 GHz, and those arising from the v=5 level of the B state are about 1/10 as strong as those arising from the v=6 and higher levels. In addition, the signal from the allowed direct photodetachment of C2− X state, which would produce a smooth background cross section, is not observed, indicating that it is less than the 103 peak to background contrast ratio. A rotational analysis of the nine bands of the C2− B–X transition observed in this study, coupled with previous measurements provides a new, more precise set of spectroscopic constants for these states. These constants are then used to generate RKR potential curves for the B and X states of C2−. Based on all C2− data, the only consistent interpretation of the observations is that the electron affinity of C2 is bounded by 3.374 eV ?EA(C2)?3.408 eV. The autodetachment rate into (C2 a 3Πu+e) is deduced to be much faster than the rate into (C2 X 1Σg++e), probably as a result of strongly R dependent configuration interaction in the C2− B state. The weakness in the direct photodetachment process is attributed to poor vibrational overlap between the initial and final states.
• Vibrationally resolved spectra of C₂–C₁₁ by anion photoelectron spectroscopy
  作者：D. W. Arnold、S. E. Bradforth、T. N. Kitsopoulos、D. M. Neumark

  DOI：10.1063/1.461211

  日期：1991.12.15

  Anion photoelectron spectroscopy has been employed to obtain vibrationally resolved spectra of the carbon molecules C2–C11. The spectra of C−2–C−9 are dominated by linear anion to linear neutral photodetachment transitions. Linear to linear transitions contribute to the C−11 spectrum, as well. From these spectra, vibrational frequencies and electron affinities are determined for the linear isomers of C2–C9 and C11. The term value is also obtained for the first excited electronic state of linear C4. The spectra of C−10 and C−11 show evidence for transitions involving cyclic anions and/or neutrals. Similar types of transitions are identified in the spectra of other smaller molecules, specifically C−6, C−8, and to a lesser extent C−5.