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4-CN-C5H4N |
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in 4-Cyanopyridine |
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14N nqcc's in
4-cyanopyridine were first determined by Heineking and Dreizler [1]
and, subsequently, under conditions of high resolution, by Vogt et al.
[2].
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Calculation was made here of the nqcc's on a structure optimized at the B3P86/6-31G(3d,3p)
level of theory, and on an reSE structure derived in ref. [2]. These are compared with the experimental nqcc's [2] in Tables 1 and 2.
Structure parameters are given in Table 3, rotational constants in Table 4. |
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In Tables 1 and 2, RMS is the
root mean square difference between calculated and experimental nqcc's
(percent of 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 nqcc's. |
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Table 1. Pyridinic 14N nqcc's in 4-Cyanopyridine (MHz). Calc (1)
was made on the B3P86/6-31G(3d,3p) ropt structure, Calc (2) on reSE structure.
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Calc (1)
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Calc (2)
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Expt [2] |
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Xaa |
-
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5.064
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5.062 |
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5.0279(19) |
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Xbb |
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1.397
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1.402 |
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1.4000(64) |
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Xcc |
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3.668
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3.660 |
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3.6279(66) *
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RMS
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0.031 (0.86 %)
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0.027 (0.75 %) |
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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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* Calculated here from zero trace condition.
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Table 2. Cyano 14N nqcc's in 4-Cyanopyridine (MHz). Calc (1)
was made on the B3P86/6-31G(3d,3p) ropt structure, Calc (2) on reSE structure. |
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Calc (1)
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Calc (2)
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Expt [2] |
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Xaa |
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4.359
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4.360 |
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4.3318(20) |
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Xaa |
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2.195
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2.198 |
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2.1196(56) |
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Xaa |
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2.164
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2.161 |
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2.2122(59) *
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RMS
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0.054 (1.9 %) |
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0.056 (2.0 %) |
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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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* Calculated here from zero trace condition. |
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| Table 3. 4-Cyanopyridine: Molecular structure parameters, ropt and reSE [2] (Å
and degrees). |
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| ropt |
reSE |
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N(1)C(2) |
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1.3329 |
1.3351(4) |
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C(2)C(3) |
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1.3884 |
1.3890(5) |
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C(3)C(4) |
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1.3956 |
1.3921(5) |
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C(2)H |
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1.0870 |
1.0815(5) |
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C(3)H |
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1.0830 |
1.0792(5) |
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C(4)C(7) |
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1.4302 |
1.4368(7)
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C(7)N(8) |
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1.1575 |
1.1573(6)
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C(6)N(1)C(2) |
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117.36 |
117.30(3) |
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N(1)C(2)C(3) |
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123.89 |
123.81(5) |
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C(2)C(3)C(4) |
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118.04 |
118.01(5) |
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C(3)C(4)C(5) |
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118.80 |
119.06(6) |
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N(1)C(2)H |
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116.08 |
116.16(9) |
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C(2)C(3)H |
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121.11 |
121.05(9) |
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| Table 5. 4-Cyanopyridine. Rotational Constants
(MHz). |
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Calc ropt |
Expt. [1,2] |
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A |
6045. |
6000.6683(44) |
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B |
1549. |
1541.178819(41) |
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C |
1233. |
1226.000890(37) |
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[1] N.Heineking and H.Dreizler, Z.Naturforsch.
42a,83(1987). |
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[2] N.Vogt, K.P.Rajappan Nair, J.-U.Grabow, J.Demaison, Mol.Phys. 116(23-24),3538(2018).
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R.G.Ford, J.Mol.Spectrosc. 58,178(1975). |
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Pyridine |
4-Fluoropyridine |
4-Chloropyridine |
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Benzonitrile |
4-Bromopyridine |
4-Methylpyridine |
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2-Cyanopyridine |
3-Cyanopyridine |
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Table of Contents
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Molecules/Nitrogen |
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4CNPYR.html |
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Last
Modified 2 Sept 2018 |
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