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H2C=CH-CC-CC-CN
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in Vinylcyanodiacetylene |
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Calculation of the nitrogen
nqcc's in vinylcyanodiacetylene was made on a rc molecular structure derived
ab initio
as discussed here. These are compared with the experimental
nqcc's of Thornwirth et al. [1] in Table 1. Structure
parameters are given in Table 2, rotational constants in Table 3. |
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In Table 1, subscripts a,b,c refer to the principal axes of the inertia
tensor, subscripts 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 plane of the molecule. Ø (degrees)
is the angle between its subscripted parameters. ETA = (Xxx
- Xyy)/Xzz. |
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RSD is the residual stand deviation
of calibration of the B3PW91/6-311+G(df,pd) model for calculation of
the 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 vinylcyanodiacetylene (MHz). Calculation was
made on the rc structure given below in Table 2. |
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Calc. |
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Expt. [1] |
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14N |
Xaa |
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4.227 |
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4.2(1) |
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Xbb |
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2.107 |
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2.1(2) |
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Xcc |
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2.120 |
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2.1 * |
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|Xab| |
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0.547 |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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2.154 |
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Xyy |
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2.120 |
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Xzz |
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4.274 |
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ETA |
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0.008 |
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Øz,a |
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4.90 |
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Øa,CN |
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4.68 |
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Øz,CN |
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0.22 |
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* Calculated here from zero trace condition.. |
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| Table 2. Vinylcyanodiacetylene (Cs). Heavy atom structure
parameters, rc (Å and degrees). The complete structure is given here in Z-matrix format. |
| For calculation of the CH, C-C, and C=C bond lengths, see here. For calculation of the CC triple bonds, see here. Interatomic angles are those given by MP2/6-311+G(d,p) optimization. |
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| Angles are exaggerated. |
Parameter |
rc |
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C(1)C(2) |
1.3340 |
| C(2)C(6) |
1.4206 |
| C(6)C(7) |
1.2144 |
| C(7)C(8) |
1.3594 |
| C(8)C(9) |
1.2145 |
| C(9)C(10) |
1.3680 |
| C(10)N |
1.1622 |
| C(1)C(2)C(6) |
123.40 |
| C(2)C(6)C(7) |
176.62 |
| C(6)C(7)C(8) |
177.05 |
| C(7)C(8)C(9) |
177.35 |
| C(8)C(9)C(10) |
177.46 |
| Click on image to enlarge. |
C(9)C(10)N |
179.67 |
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| Table 3. Rotational Constants
(MHz). |
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Calc. rc |
Expt. [1] |
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A |
36 482.7 |
36 061.(41) |
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B |
568.9 |
569.198 74(5) |
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C |
560.1 |
560.089 14(5) |
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[1] S.Thorwirth, M.C.McCarthy, J.B.Dudek,
and P.Thaddeus, J.Chem.Phys. 122,184308(2005). |
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H2C=CHCN
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Vinylcyanoacetylene
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HCCCN |
t-Cyanovinylacetylene |
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Table of Contents |
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Molecules/Nitrogen |
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CH2CHCCCCCN.html |
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Last
Modified 1 Nov 2007 |
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