C7H14N2 O2



 








 








Nitrogen

Nuclear Quadrupole Coupling Constants


in N-Acetyl-L-Valinamide


 


















Nitrogen nqcc's in C7 and C5 conformers of N-acetyl-L-valinamide  (Ac_Val_NH2) were determined by León et al. [1].  Calculation of the nqcc tensors was made here on B3P86/6-31G(3d,3p) structures.  These structures are given here in z-matrix format.  Calculated and experimental nqcc's are compared in Tables 1 and 2, rotational constants in Table 3.











C7

C5





































 








In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia tensor.  RMS is the root measn square difference between calculated and experimental nqcc's.  RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd)  model for calculation of the efg's/nqcc's.

 








 








 
 





Table 1.  14N nqcc's in C7 conformer of Ac_Val_NH2 (MHz).  Calculation was made on B3P86/6-31G(3d,3p) optimized structure.  Nc and Nt are respectively the central and terminal nitrogen.
 
 








Calc
Expt. [1]
 







Nc Xaa
1.958
2.024(5)


Xbb -
 2.886
 -
 2.987(11)


Xcc
0.928
0.962(11)


Xab
0.560




Xac -
 0.041




Xbc
2.195




 






RMS
0.072 (3.6 %)




RSD
0.030 (1.3 %)




 





Nt Xaa -
 0.457
 -
 0.769(7)


Xbb
1.888
1.902(13)


Xcc -
 1.431
 -
 1.133(13)


Xab -
 0.685




Xac -
 2.427




Xbc -
 0.387












RMS
0.249 (20. %)




RSD
0.030 (1.3 %)




 






 








 








 
 





Table 2.  14N nqcc's in C5 conformer of Ac_Val_NH2 (MHz).  Calculation was made on B3P86/6-31G(3d,3p) optimized structure.  Nc and Nt are respectively the central and terminal nitrogen.
 
 








Calc
Expt. [1]
 







Nc Xaa
2.159
2.170(11)


Xbb -
 2.199
 -
 2.286(14)


Xcc
0.040
0.116(14)


Xab
0.539




Xac -
 0.082




Xbc -
 2.538




 






RMS
0.066 (4.3 %)




RSD
0.030 (1.3 %)




 





Nt Xaa
0.199
0.613(12)


Xbb -
 0.891 -
 0.925(15)


Xcc
0.692
0.312(15)


Xab -
 2.262




Xac -
 1.623




Xbc -
 1.946












RMS
0.325 (53. %)




RSD
0.030 (1.3 %)




 






 








 













Table [3]  Ac_Val_NH2 Rotational Constants (MHz).  Calc = B3P86/6-31G(3d,3p) structures.








 Calc
     Expt [1]






C7 A
 1399.0
 1388.6071(22)

 
 B
   843.0
   840.91159(42)


C
   619.7
   619.86354(17)






C5 A
 1329.9
 1353.8151(58)


B
   835.8
   826.98719(28)


C
   660.2
   657.16182(21)







 








  








[1] I.León, E.R.Alonso, S.Mata, C.Cabezas, M.A.Rodriquez, J.-U.Grabow, and J.L.Alonso, Phys.Chem.Chem.Phys. 19,24985(2017).

 








 








Table of Contents




Molecules/Nitrogen




 








 













AcValNH2.html






Last Modified 5 Nov 2017