2-Cl-C5H4N




 







 







 







 







 








Nitrogen and Chlorine


Nuclear Quadrupole Coupling Constants


in 2-Chloropyridine


 








 








 


 





Chlorine and nitrogen nqcc's in 2-chloropyridine were determined by Meyer, Andersen, and Dreizler [1].  Previous measurements of the chlorine nqcc's had been reported by Walden and Cook [2], Scappini and Guarnieri [3], and Doraiswany and Sharma [4].

 








Calculation was made here of the nitrogen and chlorine nqcc's on the B3P86/6-31G(3d,3p) optimized molecular structure.  These are compared with the experimental values in Tables 1 and 2.  Structure parameters are given in Table 3, atomic coordinates in Table 4, and rotational constants in Table 5.

 








In Tables 1 and 2, 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 2-Chloropyridine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.
   







[a] 35Cl species, and [b] 37Cl species.

 









Calc.
Expt. [1]
   







14N [a] Xaa - 0.094 - 0.09(2)


Xbb - 2.917 - 2.94(2)


Xcc
3.012
3.03(3)


|Xab|
2.897



 







RMS
0.02 (0.8 %)




RSD
0.030 (1.3 %)



 






  Xxx
1.716
1.71 *


Xyy
3.012
3.03


Xzz - 4.728 - 4.74


ETA
0.274
0.278


z,a
57.99
58.1


a,bi
57.81
57.81


z,bi **
  0.17
  0.3

 






14N [b] Xaa - 0.093 - 0.07(4)


Xbb - 2.918 - 2.99(6)


Xcc
3.012
3.06(7)


|Xab|
2.896



 







RMS
0.05 (2.5 %)




RSD
0.030 (1.3 %)



 







 








* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.

** The z-axis makes an angle of 0.17o with the external bisector ( 'bi' ) of the C(6)N(1)C(2) angle, and tilts toward C(6).

 








 








   







Table 2.  Chlorine nqcc's in 2-Chloropyridine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.
   










Calc.
Expt. [1]
   







35Cl Xaa - 70.85 - 70.42(4)


Xbb
40.60
39.69(2)


Xcc
30.25
30.73(4)


|Xab|
  0.14




 





  RMS
0.64 (1.4 %)




RSD
0.49 (1.1 %)



   





  Xxx
40.60
39.69 *


Xyy
30.25
30.73


Xzz - 70.85 - 70.42


ETA - 0.146 - 0.127


z,a
0.07
0.07


a,CCl
0.26
0.26


z,CCl
0.19
0.19

 






37Cl Xaa - 55.84 - 55.47(5)



Xbb
31.99
31.23(8)


Xcc
23.84
24.24(9)


|Xab|
  0.09



 







RMS
0.54 (1.5 %)




RSD
0.44 (1.1 %)



 







 








* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.

 







 
 




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







2-Cl-Pyridine Pyridine








C(2)Cl
1.7401


N(1)C(2)
1.3168 1.3336


C(2)C(3)
1.3926 1.3904


C(3)C(4)
1.3859 1.3885


C(4)C(5)
1.3907 1.3885


C(5)C(6)
1.3874 1.3904


C(6)N(1)
1.3357 1.3336


C(3)H(3)
1.0826 1.0845


C(4)H(4)
1.0848 1.0851


C(5)H(5)
1.0835 1.0845


C(6)H(6)
1.0869 1.0880


C(6)N(1)C(2)
116.98 117.03


N(1)C(2)C(3)
124.96 123.80


C(2)C(3)C(4)
117.18 118.44


C(3)C(4)C(5)
119.17 118.50


C(4)C(5)C(6)
118.18 118.44


C(5)C(6)N(1)
123.54 123.80


N(1)C(2)Cl(2)
116.57


C(2)C(3)H(3)
120.58 120.21


C(3)C(4)H(4)
120.06 120.75


C(4)C(5)H(5)
121.39 121.35


C(5)C(6)H(6)
120.80 120.26



 








 














Table 4.  2-Chloropyridine.  Atomic coordinates, ropt.  Normal species.
 







 a ()
 b ()







Cl(2)
2.1331
0.0113

N(1) - 0.1906 - 1.1772

C(2)
0.3930
0.0033

C(3) - 0.2766
1.2243

C(4) - 1.6619
1.1866

C(5) - 2.3064 - 0.0458

C(6) - 1.5262 - 1.1930

H(3)
0.2758
2.1554

H(4) - 2.2307
2.1103

H(5) - 3.3875 - 0.1172

H(6) - 1.9851 - 2.1783


 








 












Table 5.  2-Chloropyridine.  Rotational Constants (MHz).   Normal species.
 




Calc ropt     Expt. [1]





A 5920.1 5872.0279(6)

B 1641.1 1637.8348(1)

C 1284.9 1280.5136(1)



 









 









[1] M.Meyer, U.Andresen, and H.Dreizler, Z.Naturforsch. 42a,197 (1987).

[2] R.T.Walden and R.L.Cook, J.Mol.Spectrosc. 52,244(1974).

[3] F.Scappini and A.Guarnieri, Z.Naturforsch. 27a,1011(1972).

[4] S.Doraiswany and S.D.Sharma, CurrentSci. 42,511(1972).

 









 








Pyridine 3-Chloropyridine 4-Chloropyridine

2-Fluoropyridine 3-Fluoropyridine 4-Fluoropyridine

2-Bromopyridine 3-Bromopyridine 4-Bromopyridine

 








 








Table of Contents





Molecules/Nitrogen




Molecules/Chlorine




 








 













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Last Modified 15 Nov 2003