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CH2CH2CHCN |
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Nitrogen |
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Nuclear
Quadrupole Coupling Constants |
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in Cyclopropyl Cyanide |
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Calculation of the nitrogen nqcc's in cyclopropyl cyanide was made on an ropt
structure obtained by MP2/6-311+G(2d,p) optimization (see below). These are
compared with the experimental nqcc's [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 b-axis, these are perpendicular to the molecular symmetry plane.
Ø (degrees) is the angle between its subscripted
parameters. ETA = (Xxx - Xyy)/Xzz. |
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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 for the B3PW91/6-311+(df,pd) model
for calculation of the nitrogen nqcc's. |
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Table 1. Nitrogen
nqcc's in cyclic CH2CH2CHCN (MHz). Calculation was made on the ropt
structure. |
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Calc. |
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Expt. [1] |
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14N |
Xaa |
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3.440 |
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3.45976(82) |
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Xbb |
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1.678 |
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1.74564(90) |
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Xcc |
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1.762 |
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1.71412(90) |
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|Xac| |
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2.017 |
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RMS |
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0.049 (2.1 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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2.452 |
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Xyy |
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1.678 |
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Xzz |
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4.131 |
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ETA |
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0.187 |
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Øz,a |
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18.89 |
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Øa,CN |
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18.69 |
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Øz,CN |
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0.20 |
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| Table 2. Cyclopropyl Cyanide. Molecular structure parameters, ropt and heavy atom rs [4] (Å and degrees). |
| ropt = MP2/6-311+G(2d,p) optimization with corrected MP2/6-311+G(d,p) CN bond length [2]. Z-Matrix |
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ropt |
rs [5] |
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CN |
1.1574 |
1.161(4) |
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C(1)C |
1.4378 |
1.420(6) |
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C(1)C(2,3) |
1.5175 |
1.529(5) * |
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C(2)C(3) |
1.5001 |
1.500(3) * |
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CHs |
1.0825 |
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CHc |
1.0818 |
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CHt |
1.0818 |
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C(1)CN |
179.67 |
179.3(7) |
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CC(1)Hs |
114.77 |
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C(1)C(3)Hc |
116.60 |
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C(2)C(3)Hc |
117.82 |
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C(1)C(3)Ht |
116.43 |
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C(2)C(3)Ht |
118.46 |
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HcCHt |
115.77 |
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| * The substitution structure
of the ring was previously determined by Pearson et al. [5]. They
find C(1)C(2,3) = 1.528(5) Å and C(2)C(3) = 1.500(2) Å. |
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| Table 3. Cyclopropyl Cyanide. Rotational constants, ropt (MHz). |
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Calc. |
Expt. [1] |
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A |
15 863.8 |
15 786.270(20) |
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B |
3 467.1 |
3 465.107(4) |
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C |
3 287.8 |
3 286.241(4) |
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[1] L.Bizzocchi, C.Delgi Esposti, L.Dore, and Z.Kisiel, J.Mol.Spectrosc. 251,138(2008). |
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[2] J.Demaison, J.Coslèou, R.Bocquet, and A.G.Lesarri, J.Mol. Spectrosc. 167,400(1994). |
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[4] M.D.Harmony, R.N.Nandi, J.V.Tietz, J.-I.Choe, S.J.Getty, and S.W.Staley, J.Am.Chem.Soc. 105(3947(1983). |
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[5] R.Pearson Jr., A.Chopin, and V.Laurie, J.Chem.Phys. 62,4859(1975). |
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Also ... |
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O.Böttcher, N.Heineking, and D.H.Sutter, Z.Naturforsch. 44a,655(1989). Xaa = -3.4536(35), Xbb = 1.7468(51), and Xcc = 1.7068(51) MHz. |
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R.D.Brown, P.D.Godfrey, and A.L.Ottrey, J.Mol.Spectrosc. 81,303(1980). Xaa = -3.453(11) and Xbb = 1.759(16) MHz. |
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CH2CH2CHCl |
3-Cyanocyclopropene
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Table of Contents |
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Molecules/Nitrogen |
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CH2CH2CHCN.html |
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Last
Modified 1 April 2008 |
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