4-CN-C5H4N

























 








Nitrogen


Nuclear Quadrupole Coupling Constants


in 4-Cyanopyridine


 








 








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].


 









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.

 








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.

 








 








   








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.


 









Calc (1)

Calc (2)

Expt [2]
   








Xaa -
5.064
- 5.062 - 5.0279(19)

Xbb
1.397

1.402
1.4000(64)

Xcc
3.668

3.660
3.6279(66) *


 







RMS

0.031 (0.86 %)

0.027 (0.75 %)



RSD

0.030 (1.3 %)
0.030 (1.3 %)



 








 








* Calculated here from zero trace condition.


 









 









   








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.
   










Calc (1)

Calc (2)

Expt [2]
   








Xaa -
4.359
- 4.360 - 4.3318(20)

Xaa
2.195

2.198
2.1196(56)

Xaa
2.164

2.161
2.2122(59) *


 








RMS

0.054 (1.9 %)
0.056 (2.0 %)



RSD

0.030 (1.3 %)
0.030 (1.3 %)



 








 








* Calculated here from zero trace condition.

 







 
 




Table 3.  4-Cyanopyridine:  Molecular structure parameters, ropt and reSE [2] ( and degrees).
 








  ropt    reSE








N(1)C(2)
1.3329 1.3351(4)


C(2)C(3)
1.3884 1.3890(5)


C(3)C(4)
1.3956 1.3921(5)


C(2)H
1.0870 1.0815(5)


C(3)H
1.0830 1.0792(5)


C(4)C(7)
1.4302 1.4368(7)


C(7)N(8)
1.1575 1.1573(6)


C(6)N(1)C(2)
117.36 117.30(3)


N(1)C(2)C(3)
123.89 123.81(5)


C(2)C(3)C(4)
118.04 118.01(5)


C(3)C(4)C(5)
118.80 119.06(6)


N(1)C(2)H
116.08 116.16(9)


C(2)C(3)H
121.11 121.05(9)



 








 












Table 5.  4-Cyanopyridine.  Rotational Constants (MHz). 
 




Calc ropt Expt. [1,2]





A   6045. 6000.6683(44)

B   1549. 1541.178819(41)

C   1233. 1226.000890(37)



 









 









[1] N.Heineking and H.Dreizler, Z.Naturforsch. 42a,83(1987).

[2] N.Vogt, K.P.Rajappan Nair, J.-U.Grabow, J.Demaison, Mol.Phys. 116(23-24),3538(2018).












R.G.Ford, J.Mol.Spectrosc. 58,178(1975).

 









 








Pyridine 4-Fluoropyridine 4-Chloropyridine

Benzonitrile 4-Bromopyridine 4-Methylpyridine

2-Cyanopyridine 3-Cyanopyridine

 








 








Table of Contents





Molecules/Nitrogen




 








 













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Last Modified 2 Sept 2018