CH3N=C=O































 









Nitrogen


Nuclear Quadrupole Coupling Constants


in Methylisocyanate


 








 








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












In Table 1, these calculated nqcc's are compared with the experimental values of Kasten and Dreizler [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 Z-matrix format in Table 2.

 








 








   







Table 1.  14N nqcc's in CH3N=C=O (MHz).  Calculation was made on ropt molecular structures given by B3LYP/6-311+G(3df,3pd) and MP2/6-311+G(3df,3pd) optimization.
   









Calc. B3LYP
Calc. MP2
Expt. [1]
   







Xaa
2.883
2.876
2.8358(75)

Xbb - 1.275 - 1.231 -
 1.288(21)

Xcc - 1.608 - 1.646 -
 1.548(21)

|Xab|
0.352
0.288



 







RMS
0.044 (2.4 %)
0.069 (3.7 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx - 1.305 - 1.251



Xyy - 1.608
 - 1.646



Xzz
2.912
2.896



ETA
0.104
0.136



Øz,a
  4.81
  4.00



Øa,N=C
15.73
16.68



Øz,N=C
20.54
20.68



 








 

















 
 






Table 2.  CH3N=C=O.  Structure parameters, B3LYP/6-311+G(3df,3pd) and MP2/6-311+G(3df,3pd) (Å and degrees).
 








 H
 C,1,B1
 N,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 O,4,B4,3,A3,2,D2,0
 H,2,B5,3,A4,4,D3,0
 H,2,B6,3,A5,4,D4,0










   B3LYP
    MP2

 B1=1.0868411
 B2=1.43902939
 B3=1.19610491
 B4=1.17164654
 B5=1.09027826
 B6=1.09027826
 A1=108.98260395
 A2=140.25150117
 A3=173.77876285
 A4=110.91716809
 A5=110.91716809
 D1=180.
 D2=180.
 D3=-60.61755326
 D4=60.61755326
  B1=1.08464303
 B2=1.43988008
 B3=1.20677858
 B4=1.17833999
 B5=1.08766743
 B6=1.08766743
 A1=108.62451003
 A2=137.90286556
 A3=172.85603883
 A4=110.66709819
 A5=110.66709819
 D1=180.
 D2=180.
 D3=-60.62953142
 D4=60.62953142



 








 








[1] W.Kasten and H.Dreizler, Z.Naturforsch. 41a,637(1986).

 








R.G.Lett and W.H.Flygare, J.Chem.Phys. 47,4730(1967):  Xaa = 2.86(3) MHz





















HNCO
CH2C(H)NCO (CH3)3CNCO
 CH3CH2NCO

 


















Table of Contents




Molecules/Nitrogen




 








 













CH3NCO.html






Last Modified 16 Dec 2015