Microwave Spectrum, Ring‐Puckering Potential Function, Ring Structure, and Dipole Moment of Cyclobutanone
Microwave Spectrum, Ring‐Puckering Potential Function, Ring Structure, and Dipole Moment of Cyclobutanone
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DOI：
10.1063/1.1669813
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发表时间：
1968-07
影响因子：
4.4
通讯作者：
L. Scharpen;V. Laurie
中科院分区：
文献类型：
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作者：
L. Scharpen;V. Laurie
对环丁酮的基态和环皱振动的前10个激发态的微波光谱进行了归属。观察到的转动常数随环皱态和远红外光谱变化的大部分特征都可以用环皱势函数V（Z）= ν 0 [12Z2 + 0.4918Z4 + 1.598 exp（− 1.0Z2）]来解释，其中ν 0 = 29.85 cm − 1。Z是环起皱运动的无量纲坐标。在平面环构象中存在7.6 ± 2 cm −的势垒，其中π = 0的能级位于势垒顶部上方9.2 cm − 1处。讨论了π = 8态的微扰。三个13 C单取代物种的基态转动光谱也已被指定，并确定了环的结构。以C1为碳原子，其余碳原子依次编号，环的结构参数为：r（C1C2）= 1.527 ± 0.003A，r（C2C3）= 1.556 ± 0.001A，α C2C1C2 ′ = 93.1 ± 0.3 °，α C1C2C3 = 88.0 ± 0.3 °，α C2C3C2 ′ = 1.527 ± 0.001A，α C2C3C2 ′ = 1.556 ± 0.001A，α C2C3C2 ′ = 1.556 ± 0.001A，α C2C3C2 ′ = 1.556 ± 0.001A，α C2C3C3C2 ′ = 1.567 ± 0.001A，α C2C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C
The microwave spectrum of cyclobutanone in the ground state and the first 10 excited states of the ring‐puckering vibration has been assigned. Most features of the observed variation of rotational constants with ring‐puckering state and of the far‐infrared spectrum are accounted for with the ring‐puckering potential function V(Z) = ν0[12Z2 + 0.4918Z4 + 1.598 exp(−1.0Z2)], with ν0 = 29.85 cm−1. Z is a dimensionless coordinate for the ring‐puckering motion. A barrier of 7.6 ± 2 cm− exists at the planar ring conformation; with the υ = 0 level lying 9.2 cm−1 above the top of the barrier. A perturbation of the υ = 8 state is discussed. The ground‐state rotational spectra of the three 13C monosubstituted species have also been assigned and the structure of the ring determined. With the carbonyl carbon labeled C1 and other carbons numbered sequentially around the ring, the ring structural parameters are r(C1C2) = 1.527 + 0.003 A, r(C2C3) = 1.556 ± 0.001 A, ∠C2C1C2′ = 93.1 ± 0.3°, ∠C1C2C3 = 88.0 ± 0.3°, ∠C2C3C2′ ...