5-F-C4N2H3




 







 


Nitrogen


Nuclear Quadrupole Coupling Constants


in 5-Fluoropyrimidine


 








 

 




Nitrogen nqcc's in 5-fluoropyrimidine were calculated on a structure given by B3P86/6-31G(3d,3p) optimization.  These nqcc's are given in Table 1.  Structure parameters are given in Table 2, atomic coordinates in Table 3, rotational 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.  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. Nitrogen nqcc's in 5-Fluoropyrimidine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.
 










Calc.
Expt. 
 







14N(1,3) Xaa - 0.111


Xbb -
 3.265



Xcc 3.375


Xab ± 2.733


 








RSD 0.030 (1.3 %)
 








Xxx 1.468


Xyy 3.375


Xzz -
 4.843



ETA
0.394



Øz,a
59.99



Øa,bi
58.24



Øz,bi*
  1.75

   







 








* The z-axis makes an angle of 1.75o with the external bisector ( 'bi' ) of the C(6)N(1)C(2) angle, and tilts toward C(6).

 







 
Table 2.  5-Fluoropyrimidine and Pyrimidine.  Structure parameters ropt (Å and degrees).
 
X = F X = H
C(2)N(3) 1.3317 1.3320
N(3)C(4) 1.3310 1.3328
C(4)C(5) 1.3842 1.3877
C(2)H(2) 1.0864 1.0876
C(4)H(4) 1.0872 1.0879
C(5)X(5) 1.3353 1.0835
N(1)C(2)N(3) 127.12 127.38
C(2)N(3)C(4) 116.39 115.70
N(3)C(4)C(5) 120.66 122.40
C(4)C(5)C(6) 118.78 116.44
C(5)C(4)H(4) 120.87 121.16
 
 
Table 3.  5-Fluoropyrimidine.  Atomic coordinates, ropt.
 
 a (Å)  b (Å)
N(1,3) - 1.1766 ± 1.1924
C(2) - 1.7695 0.0
C(4,6) 0.1543 ± 1.1913
C(5) 0.8592 0.0
H(2) - 2.8559 0.0
H(4,6) 0.6734 ± 2.1466
F(5) 2.1945 0.0
 
 
Table 4.  5-Fluoropyrimidine.  Rotational Constants (MHz).
 
Calc. ropt Expt. 
A  6076.4
B  2711.1
C  1874.7
 

 







Pyrimidine 5-Chloropyrimidine
2-Fluoropyrimidine 5-Cyanopyrimidine
4-Fluoropyrimidine

 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 24 Feb 2004