C3H5N































 








Nitrogen


Nuclear Quadrupole Coupling Constants


in 3-Methyl-2H-Azirine


 








 








 








The microwave spectrum of 3-methyl-2H-azirine was observed by Sugie et al. [1].  Hyperfine structure due to 14N quadrupole interaction was, however, not resolved.


 









Calculation of the nitrogen nqcc tensor was made here on an ropt molecular structure derived by B3LYP/6-31G(3d,3p) optimization.  These nqcc's are given in Table 1.  Structure parameters are given in Table 2, rotational constants and electric dipole moments in Table 3, quartic centrifugal distortion constants in Table 4.


 








In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor, x,y,z to principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the symmetry plane of the molecule.  Ø (degrees) is the angle between its subscripted parameters. ETA = (Xxx - Xyy)/Xzz.

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.  Nitrogen nqcc's in 3-Me-2H-Azirine (MHz).  Calculation was made on the B3LYP/6-31G(3d,3p) optimized molecular structure.
   










Calc.
Expt.

   







14N Xaa -
1.467




Xbb - 0.411





Xcc
1.878





|Xab|
2.236




 







RSD
0.030 (1.3 %)



 







Xxx
1.359




Xyy
1.878




Xzz - 3.237




ETA
0.160




Øz,a
38.36




Øa,N=C
43.32




Øz,N=C
  4.96




 






   








 














Table 2.  3-Me-2H-Azirine.  Molecular structure parameters, ropt = B3LYP/6-31G(3d,3p) (Å and degrees).







 N
 C,1,B1
 C,2,B2,1,A1
 H,3,B3,2,A2,1,D1,0
 H,3,B4,2,A3,1,D2,0
 C,2,B5,1,A4,3,D3,0
 H,6,B6,2,A5,1,D4,0
 H,6,B7,2,A6,1,D5,0
 H,6,B8,2,A7,1,D6,0





 B1=1.25399444
 B2=1.45051644
 B3=1.08795639
 B4=1.08795639
 B5=1.47779269
 B6=1.09405845
 B7=1.09405845
 B8=1.09197254
 A1=69.20595308
 A2=120.89961506
 A3=120.89961506
 A4=140.85734751
 A5=110.06942167
 A6=110.06942167
 A7=110.65072086
 D1=99.85872536
 D2=-99.85872536
 D3=180.
 D4=121.06592461
 D5=-121.06592461
 D6=0.



 








 



Table 3.  3-Me-2H-Azirine.  Rotational Constants (MHz) and Dipole Moments (D), ropt = B3LYP/6-31G(3d,3p)






  ropt     Expt [1]





A 22610.8 22338.04(4)

B   6604.9
  6618.622(9)

C   5473.4
  5464.442(7)





a| *
2.01
1.90(5)

b| *
1.97
1.86(5)





* B3PW91/6-311+G(df,pd) on ropt structure.


 








 













Table 4.  3-Me-2H-Azirine.  Quartic Centrifugal Distortion Constants (kHz).  Calc = MP2/cc-pVTZ and B3LYP/cc-pVTZ.







MP2
B3LYP
Expt [1]






Delta_J
1.81
  1.88
1.91(6)

Delta_JK
8.42
  7.53
7.6(5)

Delta_K
73.7
  76.4
150.6(5)

delta_j
0.415
  0.431
0.443(6)

delta_k
6.07
  3.36
3.1(4)



 









 









[1] M.Sugie, H.Takeo, and C.Matsumura, J.Mol.Struct. 413-414,387(1997).


 








 








Ethylenimine 2H-Azirine
3-F-2H-Azirine




 








 








Table of Contents




Molecules/Nitrogen




 








 













3Me2HAzirine.html






Last Modified 30 Oct 2013