HC(=O)-N(H)-C6H5










 





 





 


























Nitrogen


Nuclear Quadrupole Coupling Constants

in trans-Formanilide


 








 








 


 





Calculation of the nitrogen nqcc's in formanilide was made here on molecular structures given by HF/6-311+G(d,p) and HF/6-311++G(3df,3pd) optimizations, with Cs symmetry assumed.  These are compared with the experimental nqcc's [1] in Table 1.  Structure parameters are given in Table 2, rotational constants 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.  ETA = (Xxx - Xyy)/Xzz.

RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the nitrogen nqcc's.


 








 








   








Table 1.  14N nqcc's in Formanilide (MHz).  Calculation was made on the (1) HF/6-311+G(d,p) and (2) HF/6-311++G(3df,3pd) optimized structures.
   










Calc. (1)

Calc. (2)
Expt. [1]
   








Xaa
1.863
1.843
1.926(14)

Xbb
1.718
1.709
1.745(17)

Xcc - 3.581 - 3.552 - 3.671

|Xab|
0.252
0.254



 







RMS
0.065 (2.7 %)
0.086 (3.5 %)



RSD
0.030 (1.3 %) 0.030 (1.3 %)


 







Xxx
1.528
1.514



Xyy
2.052
2.039



Xzz - 3.581 - 3.552



ETA
0.146
0.148



 








 







 
 


Table 2.  Formanilide.  Heavy atom structure parameters (Ĺ and degrees).  Complete structures are given here in Z-Matrix format.
 



ropt (1) = HF/6-311+G(d,p) optimization.

ropt (2) = HF/6-311++G(3df,3pd) optimization.
 


Point Group: Cs
ropt (1) ropt (2)





C(5)N 1.4102 1.4063
NH(13) 0.9934 0.9912
NC(14) 1.3562 1.3526
C(14)H(16) 1.0923 1.0908
C(14)O 1.1878 1.1855
C(5)NH(13) 115.53 115.50
C(5)NC(14) 129.31 129.46
NC(14)H(16) 111.08 111.08
NC(14)O 127.10 127.11



C(5)C(6) 1.3892 1.3861
C(6)C(1) 1.3868 1.3833
C(1)C(2) 1.3831 1.3797
C(2)C(3) 1.3858 1.3823
C(3)C(4) 1.3812 1.3776
C(4)C(5) 1.3919 1.3887
C(4)C(5)C(6) 119.55 119.52

C(5)C(6)C(1) 119.25 119.25

C(6)C(1)C(2) 121.40 121.45

C(1)C(2)C(3) 119.00 118.95

C(2)C(3)C(4) 120.31 120.34

C(3)C(4)C(5) 120.48 120.50



 








 



Table 3.  Formanilide.  Rotational Constants (MHz).
 




ropt (1) = HF/6-311+G(d,p) optimization.

ropt (2) = HF/6-311++G(3df,3pd) optimization.
 




  Calc. ropt (1) Calc. ropt (2)    Expt. [1]






A 4319.5 4343.5 4214.4567(14)

B 1127.0 1131.2 1123.6904(4)

C   893.8   897.5   888.0883(4)


 








 








[1] J.-R.Aviles Moreno, T.R.Huet, D.Petitprez, J.Mol.Struct. 780-781,234(2006).


 








S.Blanco, J.C.López, A.Lesarri, W.Caminati, and J.L.Alonso, Mol.Phys. 103,1473(2005):  (3/2)Xaa = 2.890(6) and (1/4)(Xbb - Xcc) = 1.354(2) MHz  ==> Xaa = 1.926(4), Xbb =  1.745, and Xcc = -3.671 MHz which, aside from the uncertainties, are the same as that given in Table 1.











P.Ottaviani, S.Melandri, A.Maris, P.G.Favero, W.Caminati, J.Mol.Spectrosc. 205,173(2001):  (Xbb - Xcc) = 5.45(6) MHz.

 









 








Formamide Acetamide N-Ethylformamide


N-Acetylglycine Dimethylamine cis-Formanilide

N-Methylacetamide Propionamide



 








 








Table of Contents




Molecules/Nitrogen




 








 













Formanilide.html






Last Modified 10 Jan 2011