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c-HCCCH-HCCN |
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in (Z)-pent-2-en-4-ynenitrile |
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Calculation of the nitrogen nqcc's in (Z)-pent-2-en-4-ynenitrile was made
on the re molecular structure of Halter et al. [1]. These are
compared with the experimental nqcc's [1] in Table 1. Structure
parameters are compared in Table 2. |
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In Table 1, RMS is the root
mean square difference between calculated and experimental diagonal
nqcc's (percentage of the average of the magnitudes of the experimental
nqcc's). RSD is the calibration residual standard deviation of
the B3PW91/6-311+G(df,pd) model for calculation of the nitrogen nqcc's,
which may be taken as a conservative estimate of the uncertainty in the
calculated nqcc's. |
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Subscripts a,b,c refer to the
principal axes of the inertia tensor; x,y,z to the principal axes
of the nqcc tensor. The nqcc y-axis is chosen coincident with the
inertia c-axis, these are perpendicular to the molecular plane.
Ø (degrees) is the angle between its subscripted
parameters. ETA = (Xxx - Xyy)/Xzz. |
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Table 1. Nitrogen
nqcc's in (Z)-pent-2-en-4-ynenitrile (MHz). Calculation was made on
the re structure of Halter et al. [1]. |
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Calc. |
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Expt. [1] |
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14N |
Xaa |
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0.269 |
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0.248(2) |
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Xbb |
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2.452 |
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2.424 * |
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Xcc |
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2.183 |
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2.176 * |
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|Xab| |
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2.941 |
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RMS |
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0.021 (1.3 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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2.149 |
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Xyy |
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2.183 |
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Xzz |
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4.332 |
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ETA |
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0.008 |
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Øz,a |
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57.41 |
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Øa,CN |
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56.90 |
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Øz,CN |
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0.51 |
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* Calculated here from Xaa and Xbb - Xcc = - 4.599(4) MHz [1]. |
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| Table 2. (Z)-pent-2-en-4-ynenitrile (Cs). Molecular structure parameters, re [1] (Å
and degrees). |
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NC(5) |
1.158 |
| C(2)C(5) |
1.427 |
| C(1)=C(2) |
1.345 |
| C(1)C(6) |
1.420 |
| C(6)C(8) |
1.207 |
| C(2)H(4) |
1.072 |
| C(1)H(3) |
1.079 |
| C(8)H(9) |
1.062 |
| NC(5)C(2) |
178.7 |
| C(1)C(2)C(5) |
122.6 |
| Click on image to enlarge. |
C(2)C(1)C(6) |
123.9 |
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C(1)C(6)C(8) |
179.5 |
| N tilts outward. |
H(4)C(2)C(1) |
119.5 |
| C(8) tilts outward. |
H(3)C(1)C(2) |
118.2 |
| H(9) tilts inward. |
C(6)C(8)H(9) |
179.2 |
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[1] R.J.Halter, R.L.Fimmen, R.J.McMahon, S.A.Peebles, R.L.Kuczkowski, and J.F.Stanton, J.Am.Chem.Soc 123,12353(2001). |
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Maleonitrile |
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CH2CHCN |
Methacrylonitrile |
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c-Crotononitrile |
t-Crotononitrile |
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Table of Contents |
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Molecules/Nitrogen |
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cHCCCH_HCCN.html |
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Last
Modified 24 Oct 2007 |
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