CH2=C(H)N=C=O

























 









Nitrogen


Nuclear Quadrupole Coupling Constants


in Vinyl Isocyanate


 








 








Calculation was made of the 14N nqcc tensor in trans and cis vinyl isocyanate on ropt structures given by B3LYP/6-311+G(3df,3pd) and MP2/6-311+G(3df,3pd) optimization. 












trans-vinyl isocyanate

cis-vinyl isocyanate























At the MP2/6-311+G(3df,3pd) level of theory, Etrans < Ecis by 2.7 kJ/mol.











In Tables 1 and 2, these calculated nqcc's are compared with the experimental values of Bouchy and Roussy [1].  Subscripts a,b,c refer to the principal axes of the inertia tensor.  Subscripts x,y,z refer to the principal axes of the nqcc tensor.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.  RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percent of average experimental nqcc).  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.  

Structure parameters are given in Table 3.

 








 








   







Table 1.  14N nqcc's in trans-CH2=C(H)N=C=O (MHz).  Calculation was made on B3LYP/6-311+G(3df,3pd) and MP2/6-311+G(3df,3pd) roptstructures.
   









Calc. B3LYP
Calc. MP2
Expt. [1]
   







Xaa
2.609
2.614
2.52(2)

Xbb - 1.526 - 1.501 -
 1.56(1)

Xcc - 1.084 - 1.113 -
 0.96(2)

|Xab|
0.611
0.545



 







RMS
0.090 (5.4 %)
0.109 (6.5 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx - 1.084 - 1.113



Xyy - 1.614
 - 1.572



Xzz
2.698
2.685



ETA
0.197
0.171



Øz,a
8.24
7.42



Øa,N=C







Øz,N=C







 








 








 








   







Table 2.  14N nqcc's in cis-CH2=C(H)N=C=O (MHz).  Calculation was made on B3LYP/6-311+G(3df,3pd) and MP2/6-311+G(3df,3pd) roptstructures.
   









Calc. B3LYP
Calc. MP2
Expt. [1]
   







Xaa
2.584
2.555
2.76(2)

Xbb - 1.417 - 1.353 -
 1.88(1)

Xcc - 1.167 - 1.202 -
 0.88(1)

|Xab|
0.957
1.001



 







RMS
0.330 (18. %)
0.376 (20. %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx - 1.167
 - 1.202



Xyy - 1.634
 - 1.598



Xzz
2.801
2.800



ETA
0.167
0.141



Øz,a
12.78
13.66



Øa,N=C







Øz,N=C







 








 

















 
 



Table 3.  CH2=C(H)N=C=O.  Heavy atom structure parameters, B3LYP/6-311+G(3df,3pd) and MP2/6-311+G(3df,3pd) (Å and degrees).  Complete structures are given here in Z-matrix format.
 




________trans_________
 _________cis__________
  trans
 B3LYP MP2B3LYP
 MP2





C(1)C(2) 1.3274 1.33281.3294
 1.3349
C(2)N 1.3897 1.39241.3886
 1.3928
NC(4) 1.2015 1.21181.2002
 1.2114
C(4)O 1.1678 1.17451.1677
 1.1743
C(1)C(2)N 122.74 121.74125.74
 125.06
C(2)NC(4) 139.76 137.32142.43
 138.27
NC(4)O 173.78 172.88173.73
 172.92



 








 








[1] A.Bouchy and G.Roussy, J.Mol.Spectrosc. 68,156(1977).

 








G.G.Brown, J.L.Neill, S.T.Shipman, and B.H.Pate, Abstract WG08, 62nd International Symposium on Molecular Spectroscopy, Ohio State University, Columbus, Ohio, 2007: Xaa = 2.63 and Xbb = -1.49 MHz in trans conformer.  Presentation.

 


















HNCO
CH3NCO
(CH3)3CNCO
 CH3CH2NCO

 


















Table of Contents




Molecules/Nitrogen




 








 













CH2CHNCO.html






Last Modified 25 Feb 2014