(CH2CH)-N=CH2


















 





 








Nitrogen

Nuclear Quadrupole Coupling Constants

in 2-Azabutadiene

(N-Vinylmethylenimine)

 








 








Nitrogen nqcc's in 2-azabutadiene were determined by Sugie et al. [1].

 








Calculation of the nitrogen nqcc tensors was made here on ropt structures given by B3LYP/6-311+G(3df,3pd) and B3LYP/aug-cc-pVTZ optimizations.  These are compared with the experimental nqcc's in Table 1.  Structure parameters are given in Table 2; rotational constants and dipole moments in Table 3; centrifugal distortion constants in Table 4.

 








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.  Ø (degrees) is the angle between its subscripted parameters. 

RMS is the root mean square difference between calculated and experimental nqcc's (percentage of the 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.

 








 








 








Table 1.  14N nqcc's in 2-Azabutadiene (MHz).  Calculation was made on (1) B3LYP/6-311+G(3df,3pd) and (2) B3LYP/aug-cc-pVTZ optimized structures.
 










Calc (1)
Calc (2)
Expt [1]
 








Xaa
0.970
0.970
0.5(10)

Xbb -
 4.792
 -
 4.791
 -
 4.4(11)

Xcc
3.822
3.821
3.9(5)

|Xab|
1.254
1.254












RMS
0.36 (12. %)
0.36 (12. %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)












Xxx
1.231
1.231



Xyy
3.822
3.821



Xzz -
 5.054
 -
 4.052



ETA
0.513
0.512



Øz,a
78.24
78.24



Øa,bi *







Øz,bi







 








 








* "bi" is bisector of CN=C angle.

 








 








 


Table 2.  2-Azabutadiene:  Structure parameters (Å and degrees).  ropt(1) = B3LYP/6-311+G(3df,3pd) and ropt(2) = B3LYP/aug-cc-pVTZ optimized structure.
 



 C
 C,1,B1
 N,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 H,1,B4,2,A3,3,D2,0
 H,1,B5,2,A4,3,D3,0
 H,2,B6,1,A5,3,D4,0
 H,4,B7,3,A6,2,D5,0
 H,4,B8,3,A7,2,D6,0


     ropt(1)      ropt(2)


 B1=1.33033177
 B2=1.39838555
 B3=1.26841888
 B4=1.08005712
 B5=1.08100374
 B6=1.09168408
 B7=1.08536114
 B8=1.09596798
 A1=121.39626182
 A2=118.21670638
 A3=121.02964664
 A4=120.53322366
 A5=120.94587949
 A6=119.4021668
 A7=123.16081646
 D1=180.
 D2=180.
 D3=0.
 D4=180.
 D5=180.
 D6=0.
  B1=1.33041298
 B2=1.39877163
 B3=1.26867478
 B4=1.08011238
 B5=1.08109835
 B6=1.09159894
 B7=1.08543277
 B8=1.09602871
 A1=121.39078122
 A2=118.1800821
 A3=121.02169912
 A4=120.5521659
 A5=120.94834225
 A6=119.40076258
 A7=123.14771547
 D1=180.
 D2=180.
 D3=0.
 D4=180.
 D5=180.
 D6=0.
 
  



 








 



Table 3.  2-Azabutadiene:  Rotational constants (MHz) and dipole moments (D):  ropt(1) = B3LYP/6-311+G(3df,3pd) and ropt(2) = B3LYP/aug-cc-pVTZ optimized structure.
 





  ropt(1)   ropt(2) Expt [1]






A   48657.
   48630.
 47186.010(23)

B     4892.
     4891.
   4886.5325(27)

C     4445.
     4444.
   4430.0673(23)






|µa|
   0.40
   0.40
 0.443(33)

|µb|   1.50
   1.50
 1.896(74)







 








 








 



Table 4.  2-Azabutadiene:  Quartic Centrifugal Distortion Constants (MHz).  Calc = B3LYP/cc-pVTZ.
 





  Calc   Expt [1]






Delta_J
 0.000955
 0.000995(11)

Delta_JK
 - 0.00804
 - 0.00801(29)

Delta_K
 0.337
 0.3406(32)

delta_j
 0.000117
 0.00011743(46)

delta_k
 0.00472
 0.005158(51)







 








 








[1]  M.Sugie, H.Takeo, and C.Matsumura, J.Am.Chem.Soc. 111(3), 906(1989).

 








 








N-Chloromethylenimine
Formaldoxime
 N-Cyanomethanimine

N-Methylmethanimine






 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 10 May 2016