Microwave spectrum, dipole moment and internal rotation potential function of gauche-cyclopropanol
Microwave spectrum, dipole moment and internal rotation potential function of gauche-cyclopropanol
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左旋环丙醇的微波谱、偶极矩和内旋势函数
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
J. Sheridan
中科院分区：
文献类型：
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作者：
J. N. MacDonald;D. Norbury;J. Sheridan
293K时，环丙醇和环丙醇-[2H1]-醇的微波光谱减慢了蒸气中的高切构象。还没有获得反式构象存在的证据。这个旋转体的光谱显示了与所有三个惯性轴上的偶极分量相关的跃迁，b型跃迁，这构成了光谱的一个可观的部分，被分成两个双峰，在正常形式下被≈8200 MHz分开，在[2h1]中被≈326 MHz分开，形成了一个关于扭转频率0-？†�0+对这些吸收的贡献的帐户。许多规范形的线条偏离刚性转子的特性。对这一形式的九个参数进行了分析，并得到了无数的双重推理的证实。该物种的0--†�0+激发能为4115.25(42)兆赫。Guche-环丙烷-[2H1]-ol的光谱可以用0+和0-态共有的一组转动常数和163.74(1.8)兆赫的0-†�0+激发能来拟合。根据斯塔克效应测量确定的[2H12]F的偶极矩分量为：µa=1.58(10)×10-30 Cm，[0.48(3)D]‘µb=3.75(50)×10-30 Cm，[1.12(15)D]；µc=2.70(57)10-30 Cm，[0.81(17)D]；以及µTotal=4.88(67)×10-30 Cm，[1.46(20)D]；羟基氢的取代坐标符合平衡的二面体内旋转角α，相对于反式构象处的零值为106°±5°。0--†�0+能量差与α的这个值和不发生稳定变换的假设结合使用，以产生内部旋转的近似势函数。分离Guche-mina的顺势垒为7.9(1.5)kJ·mol-1，反式势垒为17(6)kJ·mol-1，反式势垒为17(6)kJ·mol-1。
The Microwave spectra of cyclopropanol and cyclopropan-[2H1]-ol slow the gauche-conformation is the dominant species present in the vapour at 293K. No evidence for the existence of the trans-conformation has been obtained. The spectra of this rotamer show transitions associated with dipole components in all three inertial axes, the b-type transitions, which form an appreciable part of the spectra, being split into doublets separated by ≈ 8200 MHz in the normal form and by ≈ 326 MHz in the [2H1] form an account of contributions of the torisonal frequence 0–â†� 0+ to these absorptions. Many lines of the normal form depart from rigid rotor behaviour. An analysis has been made in terms of nine parameters for this form, and confirmed by numerous double reasonances. The 0–â†� 0+ excitation energy for this species is 4115.25(42) MHz. Spectra of gauche-cyclopropan-[2H1]-ol can be fitted to a single set of rotational constants common to the 0+ and 0– states and a 0–â†� 0+ excitation energy of 163.74(1.80) MHz. The dipole moment components of the [2H12] from are determined from Stark effect measurements as : µa= 1.58(10)× 10–30 C m, [0.48(3)D]′µb= 3.75(50)× 10–30 C m, [1.12(15) D]; µc= 2.70(57)10–30 C m, [0.81(17) D]; and µtotal= 4.88(67)× 10–30 C m, [1.46(20) D];. Substitution coordinates of the hydroxyl hydrogen accord with an equilibrium dihedral angle of internal rotation, α, of 106°± 5° relative to a zero at the trans-conformation. The 0–â†� 0+ energy differences are used in conjunction with this value of α and the assumption that no stable trans-from occurs, to yield an approximate potential function for internal rotation. The cis-barrier separating the gauche-minima is 7.9(1.5)kJ mol–1, while the barrier via the trans-conformation is 17(6) kJ mol–1, while the barrier via the trans-conformation is 17(6) kJ mol–1.