C3N3HF2



 

 








Nitrogen


Nuclear Quadrupole Coupling Constants


in Difluoro-1,3,5-Triazine


 







 

 


 




The molecular structure of difluoro-1,3,5-triazine was optimized at the B3P86/6-31G(3d,3p) level of theory.  C2V symmetry was assumed.  On this structure, calculation was made of the nitrogen nqcc's.  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 model for calculation of the nqcc's.
 

 







   







Table 1. Nitrogen nqcc's in 2,6-Difluoro-1,3,5-Triazine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.
   










Calc.
Expt.
   






14N(1) Xaa (xx) 2.023
Xbb (zz) - 3.905
Xcc (yy) 1.882
ETA - 0.036
 
RSD 0.030 (1.3 %)
 
14N(3,5) Xaa - 2.753
Xbb 0.485
Xcc 2.268
Xab ± 2.464
 
Xxx 1.814
Xyy 2.268
Xzz - 4.082
ETA 0.111
Øz,a 28.34
Øa,bi 29.50
Øz,bi *   1.16
 
 
* The z-axis makes an angle of 1.16o with the external bisector ( 'bi' ) of the C(2)N(3)C(4) angle, and tilts away from C(2).
 
 
 
Table 2.  Structure parameters, ropt (Å and degrees).  Dichloro- and Difluoro-1,3,5-Triazine, and 1,3,5-Triazine.
 
 X=Cl  X=F  X=H
N(1)C(2) 1.3253 1.3190 1.3312
C(2)N(3) 1.3252 1.3189 1.3312
N(3)C(4) 1.3307 1.3312 1.3312
C(2)X(2) 1.7158 1.3109 1.0881
C(4)H(4) 1.0871 1.0864 1.0881
C(6)N(1)C(2) 113.20 111.90 113.93
N(1)C(2)N(3) 126.92 128.16 126.07
C(2)N(3)C(4) 113.28 112.76 113.93
N(3)C(4)N(5) 126.40 126.25 126.07
N(1)C(2)X(2) 116.33 115.61 116.96


 
 
Table 3.  Difluoro-1,3,5-Triazine.  Atomic coordinates, ropt.
 
  a (Å)   b (Å)
N(1) 0.0 0.9724
C(2,6) ± 1.0928 0.2340
N(3,5) ± 1.1874 - 1.0816
C(4) 0.0 - 1.6834
F(2,6) ± 2.2242 0.8961
H(4) 0.0 - 1.6834
 
 

Table 4.  Difluoro-1,3,5-Triazine.  Rotational Constants (MHz).
 
Calc. ropt     Expt.
A  4226.7
B  1973.2
C  1345.2


 
 

1,3,5-Triazine Dichloro-1,3,5-Triazine


Trifluoro-1,3,5-Triazine Fluoro-1,3,5-Triazine
 
 

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Molecules/Nitrogen



 

 













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Last Modified 20 Feb 2004