CH3CF2CN




 
 

 





 

Nitrogen


Nuclear Quadrupole Coupling Constants


in 2,2-Difluoropropanenitrile


 







 
 
Calculation of the nitrogen nqcc tensor in CH3CF2CN was made here on an approximate equilibrium structures given by ~re (1) = MP2/6-311+G(3df,3pd) optimization with empirically corrected bond lengths and ~re (2) = MP2/aug-cc-pVTZ optimization with empirically corrected bond lengths. These nqcc's are given in Table 1.  Molecular structure parameters are given in Table 2, rotational constants and dipole moments in Table 3.
 
In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor, subscripts 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 symmetry plane of the molecule.  Ø (degrees) is the angle between its subscripted parameters. ETA = (Xxx - Xyy)/Xzz.
RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's.
 
 
   






Table 1.  14N nqcc's in CH3CF2CN (MHz).  Calculation was made on the ~re(1) and ~re(2) structures.
   








Calc (1) Calc (2)
Expt.
   





Xaa - 4.571 - 4.572
Xbb 2.156 2.157
Xcc 2.414 2.415
|Xab| 0.134 0.131
 
RSD 0.030 (1.3 %) 0.030 (1.3 %)
 
Xxx 2.159 2.160
Xyy 2.414 2.415
Xzz - 4.573 - 4.575
ETA 0.0559 0.0557
Øz,a   1.14   1.11
Øa,CN   1.84   1.89
Øz,CN   0.70   0.78
 
   
 
 
Table 2.  CH3CF2CN  Selected structure parameters, ~re(1) and ~re(2) (Å and degrees).  Complete structures are given here in Z-matrix format.
 
~re(1) ~re(2)

NC(3) 1.1557 1.1557
C(3)C(2) 1.4808 1.4800
C(2)C(1) 1.5010 1.5005
C(2)F(8,9) 1.3553 1.3552
C(1)H(5) 1.0866 1.0872
C(1)H(6,7) 1.0860 1.0868
NC(3)C(2) 177.16 177.02
C(3)C(2)C(1) 113.01 113.09
C(1)C(2)F(8,9) 110.18 110.29
C(2)C(1)H(5) 107.95 108.01
C(2)C(1)H(6,7) 109.60 109.56
 
 
Table 3.   CH3CF2CN  Rotational Constants (MHz) and Dipole Moments (D).
 
 ~re(1)  ~re(2) Expt.
A 5237.6 5240.7
B 2894.5 2897.0
C 2844.6 2844.6
 
a|   2.43   2.42
b|   2.24   2.24
c|   0 (sym)   0 (sym)


 








 







CH3CH2CN CF3CF2CN CH3CN CF3CN
CF3CH2CN
 

 








Table of Contents



Molecules/Nitrogen
 

 













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Last Modified 23 Sept 2010