C6H11NO3











 


























 









Nitrogen


Nuclear Quadrupole Coupling Constants

in N-Acetylalainemethylester (AAME)

 








 








 

 





Calculation of the 14N nuclear quadrupole coupling constant tensors in AAME was made here on ropt molecular structures given by B3P86/6-31G(d,p) and B3P86/6-31G(3d,3p) optimization.

 








Calculated and experimental [1] nitrogen nqcc's are compared in Table 1, rotational constants in Table 2.  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.  ETA = (Xxx - Xyy)/Xzz.  RMS is the root mean square difference between calculated and experiment diagonal nqcc's (percent of average magnitude of experimental nqcc's).  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.  14N nqcc's in AAME (MHz).  Calculation was made on (1) B3P86/6-31G(d,p) and (2) B3P86/6-31G(3d,3p) ropt structures.
   









Calc (1)
Calc (2)
Expt [1]
   







Xaa
2.019
1.997
2.032(3)

Xbb
1.153
1.146
1.072(3)

Xcc -
 3.172
 -
 3.143
 -
 3.104(3)

Xab -
 0.652
 -
 0.689



Xac -
 0.598
 -
 0.658



Xbc -
 1.908
-
 1.929


 







RMS
0.061 (3.0 %)
0.052 (2.5 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.584
1.583



Xyy
2.413
2.424



Xzz -
 3.997
 -
 4.007



ETA
0.207
0.210



 








 








 







 





Table 2.  Rotational Constants (MHz).  ropt(1) = B3P86/6-31G(d,p), ropt(2) = B3P86/6-31G(3d,3p).

 




ropt(1) ropt(2)      Expt [1]

 



A
 3003
 2995
 3011.8909(2)

B
  675
  675
   670.72722(5)

C
  595
  598
   596.32988(7)



 








 








[1] D.F.Plusquellic, I.Kleiner, J.Demaison, R.D.Suenram, R.J.Lavrich, F.J.Lovas, G.T.Fraser, and V.V.Ilyushin, J.Chem.Phys. 125,104312(2006).

 








 








Formamide
 Acetamide
 N-Methyformamide
 N-Acetylglycine

N-Ethylformamide
 N,N-Diethylacetamide N-Methylacetamide
 see Amides

 








 








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Molecules/Nitrogen




 








 













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Last Modified 8 Apr 2015