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g-CH2SH-CH2CN
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Nitrogen |
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Nuclear
Quadrupole Coupling Constants |
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in gauche 3-Mercaptopropionitrile
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The microwave spectra of CH2SH-CH2CN and CH2SD-CH2CN
have been investigated by Marstokk and Møllendal [1].
Three conformations were assigned, the most stable being the gauche
conformation shown above. Calculation was made here of
approximate equilibrium structures of this conformer (see below).
And on these structures, calculation was made of the nitrogen
nqcc's. |
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The calculated nqcc's are given in Tables 1 and 2 for CH2SH-CH2CN and CH2SD-CH2CN respectively.
Structure parameters are given in Table 3, rotational constants
in Table 4. |
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In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia
tensor; x,y,z to the principal axes of the nqcc tensor. Øz,CN (degrees) is the angle between the z-principal axis and the CN bond direction. ETA = (Xxx - Xyy)/Xzz. |
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RSD is the
calibration residual standard deviation for the B3PW91/6-311+G(df.pd) model
for calculation of the nitrogen nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's. |
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Table 1. Nitrogen nqcc's in g-CH2SH-CH2CN (MHz). Calculation was made on approximate equilibrium structures ~re(1) and ~re(2). |
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Calc ~re(1)
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Calc ~re(2) |
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Expt. |
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Xaa |
- |
0.145 |
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0.096 |
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Xbb |
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1.694 |
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1.746 |
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Xcc |
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1.839 |
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1.842 |
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|Xab| |
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3.014 * |
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2.997 * |
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|Xac| |
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0.809 |
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0.796 |
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|Xbc| |
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0.864 |
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0.877 |
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RSD |
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0.030 (1.3 %) |
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0.030 (1.3 %) |
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Xxx |
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2.005 |
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2.013 |
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Xyy |
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2.254 |
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2.245 |
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Xzz |
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4.259 |
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4.258 |
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ETA |
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0.059 |
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0.054 |
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Øz,CN |
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0.57 |
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0.57 |
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* The product XabXacXbc is negative. |
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Table 2. Nitrogen nqcc's in g-CH2SD-CH2CN (MHz). Calculation was made on approximate equilibrium structures ~re(1) and ~re(2). |
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Calc ~re(1)
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Calc ~re(2) |
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Expt. |
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Xaa |
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0.102 |
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0.052 |
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Xbb |
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1.748 |
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1.801 |
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Xcc |
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1.850 |
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1.854 |
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|Xab| |
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3.008 * |
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2.991 * |
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|Xac| |
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0.782 |
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0.768 |
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|Xbc| |
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0.845 |
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0.857 |
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RSD |
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0.030 (1.3 %) |
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0.030 (1.3 %) |
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* The product XabXacXbc is negative. |
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Molecular Structure |
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~re(1): After optimization at the MP2/6-311+G(d,p) and MP2/6-31G(d,p) levels of theory; C-C, CN, and CH bond lengths were corrected as described here. Interatomic angles and C-O-H geometry parameters are those given by MP2/6-311+G(d,p) optimization. |
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~re(2): After optimization at the MP2/6-311+G(3df,3pd) level of theory; C-C and CN bond lengths were corrected as described here. C-H bond lengths, interatomic angles, and C-O-H geometry parameters are those given by optimization. |
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| Table 3. g-CH2SH-CH2CN. Selected structure parameters. Complete structures are given here in Z-matrix (G03 input) format. |
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| Point Group C1 |
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~ re(1) |
~ re(2) |
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C(1)C(2) |
1.5274 |
1.5274 |
| C(2)S(7) |
1.8127 |
1.8062 |
| S(7)H(8) |
1.3367 |
1.3358 |
| C(1)C(2)S(7) |
113.40 |
113.51 |
| C(2)S(7)H(8) |
95.62 |
96.08 |
| C(1)C(9) |
1.4602 |
1.4602 |
| C(9)N(10) |
1.1563 |
1.1563 |
| C(2)C(1)C(9) |
111.39 |
110.86 |
Click on image to enlarge.
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C(1)C(9)N(10) |
177.66 |
177.47 |
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| Table 3. Rotational constants (MHz). |
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g-CH2SH-CH2CN |
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~ re(1) |
~ re(2) |
Expt. [1] |
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A |
7755.1 |
7723.4 |
7773.9116(41) |
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B |
2439.4 |
2465.6 |
2404.9015(13) |
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C |
1981.6 |
1996.5 |
1959.2031(15) |
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g-CH2SD-CH2CN |
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A |
7517.6 |
7485.9 |
7521.020(24) |
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B |
2433.1 |
2459.1 |
2401.280(19) |
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C |
1962.7 |
1977.2 |
1941.588(18) |
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[1] K.-M.Marstokk and H.Møllendal, Acta Chemica Scand. A 37,477(1983). |
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g-CH2OH-CH2CN |
gauche-1-Cyanopropane |
CH3CH2CN |
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Table of Contents |
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Molecules/Nitrogen |
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HSCH2CH2CN.html |
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Last
Modified 4 Dec 2008 |
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