C2H4NH
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Nitrogen


Nuclear Quadrupole Coupling Constants


in Ethyleneimine


 
(Aziridine)




 








 








Nitrogen nqcc's in ethyleneimine were first determined in 1968 by Kemp and Flygare [1] and later, with improved resolution, by Thorwirth et al. [2,3].  An rs structure was determined by Bak and Skaarup [4], an reSE structure by Csszr et al. [5].


 








Calculation was made here of the nqcc's on the rs and reSE structures, and on an ropt structure given by B3LYP/6-31G(3d,3p) optimization.  These are compared with the experimental nqcc's in the normal species [2] in Table 1, and with the ND species [1] in Table 2.  Structure parameters are given in Table 3, atomic coordinates in Table 4, and rotational constants in Table 5.

 








In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  (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 (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 efg's/nqcc's.

 








 








 










Table 1. 14N nqcc's in Ethyleneimine-NH (MHz).  Calculation was made on the rs, reSE, and ropt molecular structures.
 












Calc /rs
Calc /reSE
Calc /ropt
Expt. [2]
 










Xaa
0.671

0.687

0.692
0.68483

Xbb
2.171

2.164

2.178
2.17235(95)

Xcc -
2.842
-
2.851
- 2.870 - 2.85718(88)

|Xbc|
2.262

2.271

2.273














RMS
0.012 (0.61 %)
0.006 (0.34 %)
0.009 (0.47 %)


RSD
0.030 (1.3 %) 0.030 (1.3 %) 0.030 (1.3 %)














Xxx
0.671

0.687
0.692
0.68483


Xyy
3.041

3.039

3.050
3.047 *


Xzz -
3.712
-
3.727
- 3.742 - 3.732

ETA
0.638

0.631

0.630
0.633

z,c
21.03

21.09

21.00
21.05

c,NH
26.69

26.79

27.24
27.24

z,NH
47.72

47.88

48.24
48.29

z,bi **
  8.52

  8.40

  8.28
  8.31













 








* Calculated here from the diagonal experimental diagonal nqcc's and |Xbc| = 2.273 MHz.


** Angle between the z-axis and the bisector ('bi') of the angle the NH bond axis makes with the CNC plane.

 








 









 










Table 2. 14N nqcc's in Ethyleneimine-ND (MHz).  Calculation was made on the rs, reSE, and ropt molecular structures.
 












Calc /rs
Calc /reSE
Calc /ropt
Expt. [1]
 










Xaa
2.465

2.459

2.473
2.450(5)

Xbb
0.671

0.687

0.692
0.685(5)

Xcc -
3.136
-
3.146
- 3.165 - 3.135(5)

|Xac|
2.262

1.895

1.894
1.844(80)












RMS
0.012 (0.56 %)

0.008 (0.38 %)

0.018 (0.84 %)


RSD
0.030 (1.3 %)
0.030 (1.3 %)
0.030 (1.3 %)















 









 



Table 3.  Ethyleneimine.  Molecular structure parameters, rs, reSE, and ropt ( and degrees).  These structures are given here in Z-matrix format. 
Hc and Ht are cis and trans with respect to NH.





 
   rs   reSE   ropt






NH 1.016
1.01279(13)
1.0169

NC 1.475
1.47013(6)
1.4730

CC 1.481
1.47703(8)
1.4807

CHc 1.084
1.08099(13)
1.0863

CHt 1.083
1.07971(13)
1.0853

CNC   60.25
  60.311(6)
  60.35

CNH 109.31
109.376(9)
109.79

NCHc 118.26
118.28(2)
118.69

CCHc 117.75
117.829(14)
118.08

NCHt 114.27
114.46(2)
114.69

CCHt 119.32
119.538(14)
119.97

HcCHt 115.72
115.424(9)
114.63


 








 






Table 4.  Ethyleneimine-NH.  Atomic coordinates, ropt structure.
(More figures are shown than are significant.)











  a ()
  b ()
  c ()









N
0.0
0.840294 - 0.083125

H
0.0
1.305816
0.820991

C 0.740365 - 0.429721
0.009899

H 1.251640 - 0.668577
0.938088

H 1.282555 - 0.705381 - 0.888965


 








 


Table 5.  Ethyleneimine-NH.  Rotational Constants (MHz).






     ropt      Expt. [2]





A    22 881 22 736.192 853(299)

B    21 258 21 192.461 027(303)

C    13 452 13 383.163 814(289)


 








 








[1] M.K.Kemp and W.H.Flygare, J.Am.Chem.Soc. 90,6267(1968).

[2] S.Thornwirth, R.Gendriesch, H.S.P.Mller, F.Lewen, and G.Winnewisser, J.Mol.Spectrosc. 201,323(2000).

[3] S.Thorwirth, H.S.P.Mller, and G.Winnewisser, J.Mol.Spectrosc. 199,116(2000).

[4] B.Bak and S.Skaarup, J.Mol.Struct. 10,385(1971).


[5] A.G.Csszr, J.Demaison, and H.D.Rudolph, J.Phys.Chem. A, 119(9),1731(2015).

 









 








CH2NH (CH3)2NH CF2NH



trans-syn-Propenimine trans-anti-Propenimine


trans-Ethanimine cis-Ethanimine



 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 26 Oct 2014