CH3O-C6H4-NO2

























 





 









Nitrogen


Nuclear Quadrupole Coupling Constants


in 4-Nitroanisole


 








 








 








Calculation was made here of the nitrogen nqcc's in 4-nitroanisole on a structure given by B3P86/6-311+G(3d,3p) optimization with Cs symmetry assumed..  These calculated nqcc's are compared with experimental values of Graneek [1] in Table 1.  Structure parameters are given in Z-matrix format in Table 2, rotational constants in Table 3.


 








In Table 1, the subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor. (degrees) is angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.  RMS is the root mean square difference between calculated and experimental nqcc's (percent of the average experimental value).  RSD is the calibration residual standard deviation of the (1) B3PW91/6-311+G(df,pd) and (2) B3PW91/6-311+G(d,p) models for calculation of nitrogen efg's/nqcc's.


 








 








 








Table 1.  14N nqcc's in 4-Nitroanisole (MHz).  Calculation was made on the B3P86/6-311+G(3d,3p) optimized structure with both (1) B3PW91/6-311+G(df,pd) and (2) B3PW91/6-311+G(d,p) models.
 










Calc (1)

Calc (2)
Expt. [1]
 








Xaa - 1.149 -
1.126
- 1.164(2)

Xbb - Xcc -
0.792
-
0.474
-
0.569(3)


Xbb
0.179
0.326

0.298(4)*

Xcc
0.970
0.800

0.866(4)*

|Xab|

0.114

0.125













RMS
0.091 (12. %)
0.047 (6.1 %)




RSD
0.030 (1.3 %)
0.086 (3.8 %)












Xxx
0.188
0.337




Xyy
0.970
0.800



Xzz - 1.159 -
1.137




ETA
0.675
0.407




z,a
4.88

4.88




a,bi **

4.94

4.94




bi,z

0.06

0.06














 








* Derived here from experimental Xaa and Xbb - Xcc

** "bi" is bisector of ONO angle.


 








 



Table 2.  4-Nitroanisole.  Molecular structure parameters, ropt = B3P86/6-311+G(3d,3p) optimization. ( 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
 H,2,B6,1,A5,6,D4,0
 H,3,B7,2,A6,1,D5,0
 H,5,B8,4,A7,3,D6,0
 H,6,B9,1,A8,2,D7,0
 N,1,B10,6,A9,5,D8,0
 O,11,B11,1,A10,6,D9,0
 O,11,B12,1,A11,6,D10,0
 O,4,B13,3,A12,2,D11,0
 C,14,B14,4,A13,3,D12,0
 H,15,B15,14,A14,4,D13,0
 H,15,B16,14,A15,4,D14,0
 H,15,B17,14,A16,4,D15,0
      Variables:
 B1=1.38398238
 B2=1.38500967
 B3=1.39682042
 B4=1.39994618
 B5=1.39111137
 B6=1.07996151
 B7=1.07941923
 B8=1.08105574
 B9=1.07979573
 B10=1.45561963
 B11=1.21926257
 B12=1.21943601
 B13=1.34453026
 B14=1.41518198
 B15=1.08594583
 B16=1.09214115
 B17=1.09214115
 A1=119.54470263
 A2=119.67200484
 A3=120.01040206
 A4=121.39659855
 A5=119.2403932
 A6=119.32039971
 A7=118.61272329
 A8=119.29283584
 A9=119.32963208
 A10=117.66064627
 A11=117.79208645
 A12=124.20386238
 A13=118.45045456
 A14=105.91602239
 A15=111.19486431
 A16=111.19486431
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=180.
 D9=0.
 D10=180.
 D11=180.
 D12=0.
 D13=180.
 D14=-61.26912435
 D15=61.26912435


 








 



Table 3.  4-Nitroanisole:  Rotational constants (MHz), ropt= B3P86/6-311+G(3d,3p) optimized structure.
 





   ropt    Expt [1]







A 3572.0
3533.809(75)


B   592.4
  587.03009(5)


C   509.8
  505.37812(5)








 









 









[1] J.B.Graneek, C.Prez, and M.Schell, J.Chem.Phys. 147,154306(2017).


 








Nitroethene
Nitromethane
Nitrobenzene



 








 








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Last Modified 19 Oct 2017