CH2·NH·CH(CN)

 

 








Nitrogen

Nuclear Quadrupole Coupling Constants


in 2-Cyanoaziridine


 







 
 
Amino and cyano nitrogen nqcc's in the cis conformer of 2-cyanoaziridine have been determined by Brown et al. [1].
 
Calculation of the nqcc's was made here on a molecular structure given by MP2/6-311+G(3d,3p) optimization, with corrected MP2/6-311+G(d,p) optimized CN bond length.  Calculated nqcc's are compared in Tables 1 and 2 with the experimental nqcc's.  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, subscripts x,y,z 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 (percentage 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 nqcc's.
 
 
   






Table 1.  Amino Nitrogen nqcc's in 2-Cyanoaziridine (MHz).
   









Calc.
Expt. [1]
   





14N Xaa - 1.214 - 1.249(14)
Xbb 1.410 1.407(12)
Xcc - 0.197 - 0.158 *
Xab** 0.786
Xac** 2.456
Xbc** - 2.145
 
RMS 0.030 (3.2 %)
RSD 0.030 (1.3 %)
 
Xxx 0.879
Xyy 3.085
Xzz - 3.964
ETA 0.557
Øz,NH 134.42
 
   
* Derived here from zero trace condition.
** Algebraic signs of the off-diagonal components of the nqcc tensor depend on the molecular orientation with respect to the positive/negative sense (polarity) of a,b,c-coordinates.  The  algebraic sign of the product  XabXacXbc, which is negative in this case, in independent of polarity.
The algebraic signs given here correspond to the molecular orientation with respect to a,b,c coordinates given in Table 3.
 
 
   






Table 2.  Cyano Nitrogen nqcc's in 2-Cyanoaziridine (MHz).
   









Calc.
Expt. [1]
   





14N Xaa - 3.499 - 3.547(6)
Xbb 1.794 1.865(8)
Xcc 1.705 1.682 *
Xab** - 0.097
Xac** 2.127
Xbc** - 0.120
 
RMS 0.051 (2.2 %)
RSD 0.030 (1.3 %)
 
Xxx 1.764
Xyy 2.494
Xzz - 4.258
ETA 0.172
Øz,CN 0.23
 
 
* Derived here from zero trace condition.
** Algebraic signs of the off-diagonal components of the nqcc tensor depend on the molecular orientation with respect to the positive/negative sense (polarity) of a,b,c-coordinates.  The  algebraic sign of the product  XabXacXbc, which is positive in this case, in independent of polarity.
The algebraic signs given here correspond to the molecular orientation with respect to a,b,c coordinates given in Table 3.
 
   
Table 3.  2-Cyanoaziridine.  Heavy atom structure parameters (Å and degrees).  MP2/6-311+G(3d,3p) optimized structure.  Complete structure is given here in Z-matrix format.
   

N(1)H(6) 1.0157
N(1)C(2) 1.4714
C(2)C(3) 1.4892
C(3)N(1) 1.4799
C(3)C(4) 1.4423
C(4)N(5) 1.1572 *
C(3)N(1)H(6) 108.76
N(1)C(2)C(3)   59.98
C(2)C(3)N(1)   59.41
C(3)N(1)C(2)   60.61
C(2)C(3)C(4) 118.06
C(3)C(4)N(5) 178.51
* Corrected MP2/6-311+G(d,p) optimized CN bond length [2].
 
 
Table 4.  2-Cyanoaziridine.  Atomic coordinates.
 
 a (Å)  b (Å)  c (Å)
N(1) - 1.3144 0.7501 - 0.1777
C(2) - 1.3313 - 0.7201 - 0.2350
C(3) - 0.3156 - 0.1851 0.5980
C(4) 1.0537 - 0.0227 0.1448
N(5) 2.1442 - 0.0086 - 0.2420
H(6) - 0.8680 1.1150 - 1.0140
H(7) - 0.4486 0.0325 1.6678
H(8) - 2.1710 - 1.1784 0.2638
H(9) - 0.9788 - 1.206494 - 1.1326
 
 
Table 5.  2-Cyanoaziridine.  Rotational Constants (MHz).
 
Calc. ropt    Expt. [1]
A 16 900.3 16 877.718(32)
B   3 541.3   3 528.931(4)
C   3 385.6   3 373.065(4)
 
 
[1] R.D.Brown, P.D.Godfrey, and A.L.Ottrey, J.Mol.Spectrosc. 82,73(1980).
[2] J.Demaison, J.Cosléou, R.Bocquet, and A.G.Lesarri, J.Mol.Spectrosc. 167,400(1994).

 








 







CH3CN CH3CH2CN
Aziridine (Ethylenimine) c-Ethanimine

CH2NH t-Ethanimine
 

 








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Molecules/Nitrogen
 

 













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Last Modified 15 Sept 2006