2-CN-C4N2H3




 







 


Nitrogen


Nuclear Quadrupole Coupling Constants


in 2-Cyanopyrimidine


 








 


 




Nitrogen nqcc's in 2-cyanopyrimidine were calculated on a structure given by B3P86/6-31G(3d,3p) optimization.  The nqcc's are given in Tables 1 and 2.  Structure parameters are given in Table 3, atomic coordinates in Table 4, 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.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz
RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's.
 
   









 







Table 1. Ring Nitrogen nqcc's in 2-Cyanopyrimidine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.
 










Calc.
Expt. 
 







14N(1,3) Xaa - 0.368


Xbb -
2.963



Xcc 3.331


Xab ± 2.893


 








RSD 0.030 (1.3 %)
 








Xxx 1.506


Xyy 3.331


Xzz -
4.836



ETA
0.377



Øz,a
57.08



Øa,bi
58.38



Øz,bi*
  1.30

   







 








* The z-axis makes an angle of 1.30o with the external bisector ( 'bi' ) of the C(6)N(1)C(2) angle, and tilts toward C(2).

 








 








 







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










Calc.
Expt. 
 







14N Xaa - 4.480


Xbb
2.008



Xcc 2.471


ETA * 0.103


 


RSD 0.030 (1.3 %)
   






 
* ETA = (Xbb - Xcc)/Xaa = (Xxx - Xyy)/Xzz.
 
 
Table 3.  2-Cyanopyrimidine (2-CN-PRM) and Pyrimidine (PRM).  Structure parameters ropt (Å and degrees).
 
2-CN-PRM  PRM
C(2)N(3) 1.3333 1.3320
N(3)C(4) 1.3307 1.3328
C(4)C(5) 1.3885 1.3877
C(2)C(cy) 1.4455
C(cy)N 1.1556
C(4)H(4) 1.0872 1.0879
C(5)H(5) 1.0832 1.0835
N(1)C(2)N(3) 127.89 127.38
C(2)N(3)C(4) 115.36 115.70
N(3)C(4)C(5) 122.38 122.40
C(4)C(5)C(6) 116.64 116.44
C(5)C(4)H(4) 121.37 121.16
 
 
Table 4.  2-Cyanopyrimidine.  Atomic coordinates, ropt.
 
 a (Å)  b (Å)
N(1,3) - 0.1193 ± 1.1978
C(2) 0.4663 0.0
C(4,6) - 1.4499 ± 1.1816
C(5) - 2.1791 0.0
H(4,6) - 3.2623 ± 2.1507
H(5) - 1.9426 0.0
C(cy) 1.9118 0.0
N 3.0674 0.0
 
 
Table 5.  2-Cyanopyrimidine.  Rotational Constants (MHz).
 
Calc. ropt Expt. 
A  6087.9
B  1660.3
C  1304.5
 

 







Pyrimidine 2-Fluoropyrimidine
2-Chloropyrimidine 2-Bromopyrimidine
5-Cyanopyrimidine

 








 








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Molecules/Nitrogen




 








 













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Last Modified 29 Feb 2004