3-F-C5H4N






















 






 






Nitrogen


Nuclear Quadrupole Coupling Constants


in 3-Fluoropyridine


 








 








 


 





Nitrogen nqcc's in 3-fluoropyridine were first determined in 1976 by Sharma and Doraiswamy [1] and revisited in 2012 by van Eijk et al. [2].


 









Calculation of the nitrogen nqcc's was made here on a molecular structure given by B3P86/6-31G(3d,3p) optimization.  These are compared with the experimental nqcc's [2] in Table 1.  Structure parameters are given in Table 2, atomic coordinates in Table 3, rotational constants and centrifugal distortion constants in Table 4.


 








In Table 1, 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.  (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.


RMS is the root mean square differene between calculated and experimental nqcc's (percent of average experimental nqcc).  RSD is the calibration residual standard deviation of the model for calculation of the nqcc's.

 








 








   







Table 1. Nitrogen nqcc's in 3-Fluoropyridine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.

 









Calc.
Expt. [2]
   







14N Xaa - 0.035 -
0.0347(10) *



Xbb - 3.471 - 3.4659(9)



Xcc
3.506
3.5005(9)



|Xab|
2.751
2.751(7)


 







RMS
0.005 (0.20 %)




RSD
0.030 (1.3 %)



 






  Xxx
1.491
1.492(6) *



Xyy
3.506
3.5005(9)



Xzz - 4.997
4.992(6)



ETA
0.403
0.402(1)



z,a
60.99

60.97(3)



a,bi
59.72





z,bi **
  1.27




 







 








* Calculated here from the experimental 1.5(Xaa) = -0.0520(15) and  0.25(Xbb - Xcc) = -1.7416(4) MHz using Kisiel's QDIAG.f program.


** The z-axis makes an angle of 1.27o with the external bisector ( 'bi' ) of the C(6)N(1)C(2) angle.

 







 
 




Table 2.  3-Fluoropyridine and Pyridine.  Molecular structure parameters, ropt ( and degrees).
 







3-F-Pyridine Pyridine








N(1)C(2)
1.3308 1.3336


C(2)C(3)
1.3871 1.3904


C(3)C(4)
1.3819 1.3885


C(4)C(5)
1.3887 1.3885


C(5)C(6)
1.3906 1.3904


C(6)N(1)
1.3331 1.3336


C(2)H(2)
1.0870 1.0880


C(3)F(3)
1.3403


C(4)H(4)
1.0840 1.0851


C(5)H(5)
1.0843 1.0845


C(6)H(6)
1.0869 1.0880


C(6)N(1)C(2)
117.78 117.03


N(1)C(2)C(3)
121.99 123.80


C(2)C(3)C(4)
120.81 118.44


C(3)C(4)C(5)
116.96 118.50


C(4)C(5)C(6)
118.89 118.44


C(5)C(6)N(1)
123.56 123.80


N(1)C(2)H(2)
118.08 115.94


C(2)C(3)F(3)
119.32


C(3)C(4)H(4)
120.36 120.75


C(4)C(5)H(5)
120.71 121.35


C(5)C(6)H(6)
120.38 120.26



 








 














Table 3.  3-Fluoropyridine.  Atomic coordinates, ropt.
 







 a ()
 b ()







N(1) - 1.1927 - 1.1920

C(2)
0.1380 - 1.1728

C(3)
0.8558
0.0140

C(4)
0.2066
1.2339

C(5) - 1.1819
1.2081

C(6) - 1.8310 - 0.0217

H(2)
0.6633 - 2.1244

F(3)
2.1955 - 0.0292

H(4)
0.7748
2.1571

H(5) - 1.7529
2.1300

H(6) - 2.9168 - 0.0702


 








 












Table 4.  3-Fluoropyridine.  Rotational Constants (MHz) and Centrifugal Distortion Constants * (kHz).
 




Calc ropt     Expt. [2]





A 5874.4 5829.70195(13)

B 2649.6 2637.49103(7)

C 1826.0 1815.65619(6)

 



Delta_J
0.135
0.1411(17)

Delta_JK
0.302
0.296(6)

Delta_K
0.839
0.869(17)

delta_J
0.0433
0.0450(5)

delta_K
0.411
0.416(7)





* B3LYP/cc-pVTZ opt freq(vibrot)



 









 









[1] S.D.Sharma and S.Doraiswamy, J.Mol.Spectrosc. 59,216(1976).

[2] C.W. van Dijk, M. Sun, and J. van Wijngaarden, J.Phys.Chem. A 116,4082(2012).


 









M.J.S.Dewar, Y.Yamaguchi, S.Doraiswamy, S.D.Sharma, and S.H.Suck, Chem.Phys. 41,21(1979).

S.D.Sharma and S.Doraiswamy, Chem.Phys.Lett. 41,192(1976).

D.Hbner, M.Stolze, and D.H.Sutter, Z.Naturforsch. 36a,332(1981).


 









 








Pyridine 2-Chloropyridine 3-Chloropyridine

2-Fluoropyridine 4-Fluoropyridine 4-Chloropyridine

2-Bromopyridine 3-Bromopyridine 4-Bromopyridine

 








 








Table of Contents





Molecules/Nitrogen




 








 













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Last Modified 2 April 2012