2,4-F2-C6H3CN
































 








Nitrogen

Nuclear Quadrupole Coupling Constants


in 2,4-Difluorobenzonitrile


 








 








 

 





Calculation of the nitrogen nqcc's in 2,4-difluorobenzonitrile was made here on a molecular structure given by B3P86/6-31G(3d,3p) optimization.  These are compared with the experimental nqcc's of Kamaee et al. [1] in Table 1.  Structure parameters are given in Z-matrix format in Table 2, rotational constants and quartic centrifugal distortion constants in Table 3.

 








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.

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 B3PW91/6-311+G(df,pd) model for calculation of the efg's/nqcc's.

 








 








   






Table 1. Nitrogen nqcc's in 2,4-Difluorobenzonitrile (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.

 









Calc.
Expt. [1]
   






14N Xaa - 4.206 - 4.1985(17) *


Xbb
2.337
2.2882(18) *


Xcc
1.869
1.9103(18) *


|Xab|
0.763



 







RMS
0.037 (1.3 %)




RSD
0.030 (1.3 %)



 






  Xxx
2.425




Xyy
1.869




Xzz - 4.294




ETA - 0.129




Øz,a
6.56




Øa,CN
6.51




Øz,CN
0.05



 







 








* Calculated here from 1.5Xaa = -6.2977(26) and 0.25(Xbb - Xcc) = 0.09447(76) MHz [1].

 







 
 



Table 2.  2,4-Difluorobenzonitrile.  B3P86/6-31G(3d,3p) optimized molecular structure parameters, ropt (Å and degrees).
 




 C
 C,1,B1
 C,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 C,4,B4,3,A3,2,D2,0
 C,1,B5,2,A4,3,D3,0
 C,6,B6,1,A5,2,D4,0
 N,7,B7,1,A6,6,D5,0
 F,1,B8,6,A7,5,D6,0
 H,2,B9,1,A8,6,D7,0
 F,3,B10,2,A9,1,D8,0
 H,4,B11,3,A10,2,D9,0
 H,5,B12,4,A11,3,D10,0








 B1=1.3818934
 B2=1.38529111
 B3=1.38745799
 B4=1.38385966
 B5=1.39717634
 B6=1.42352862
 B7=1.1577579
 B8=1.33017373
 B9=1.08209635
 B10=1.33416644
 B11=1.08251649
 B12=1.08320978
 A1=117.34715622
 A2=122.85220638
 A3=118.38016965
 A4=122.24062163
 A5=120.66792184
 A6=151.76912231
 A7=118.96072503
 A8=121.09968344
 A9=118.2408433
 A10=119.79506396
 A11=120.30879105
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=180.
 D9=180.
 D10=180.








 












Table 3.  2,4-Difluorobenzonitrile.  B3P86/6-31G(3d,3p) Rotational Constants (MHz), and B3LYP/cc-pVTZ Centrifugal Distortion Constants (kHz).
 




Calc
     Expt. [1]





A 2940.7 2932.25895(36)

B   937.1
   933.040760(27)

C   710.7
   707.757614(19)





Delta_J
 0.0127
 0.013523(63)

Delta_JK
 0.144
 0.15751(50)

Delta_K
 0.714
 0.719(63)

delta_j
 0.00316
 0.003416(39)

delta_k
 0.0971
 0.1066(24)







 








 








[1] M.Kamaee, M.Sun, H.Luong, and J. van Wijngaarden, J.Phys.Chem. A 119(41),10279(2015).

 








 








Benzonitrile Pentafluorobenzonitrile

o-Fluorobenzonitrile 2,3-Difluorobenzonitrile

m-Fluorobenzonitrile

p-Fluorobenzonitrile

 








 








Table of Contents





Molecules/Nitrogen




 








 













23C6H3F2CN.html






Last Modified 27 Sept 2015