CH2NCN



 








Nitrogen

Nuclear Quadrupole Coupling Constants

in N-Cyanomethanimine

 








 








 








Nitrogen nqcc's in N-cyanomethanimine were determined by Winnewisser et al. [1], and by Stolze et al. [2].  A partial ro structure was determined by Bak et al. [3 - 5].

 








Calculation of the nitrogen nqcc's was made on the partial ro structure complemented here with MP2/6-31G(d,p) optimization for determination of the CH2 geometry.  These are compared with the experimental nqcc's [1,2] in Tables 1 and 2.  Structure parameters are given in Table 3.

 








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.  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.

RMS is the root mean square difference between calculated and experimental nqcc's (percentage of average experimental nqcc).  RSD is the residual stand deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's.

 








 








   







Table 1.  Imine 14N nqcc's in CH2NCN (MHz).  Calculation was made on the ro/ropt molecular structure.
 










Calc.
Expt. [1]
Expt. [2]
 








Xaa
2.090
2.057(39)
2.032(9)

Xbb - 4.539 -
 4.631(22)
 - 4.586(7)

Xcc
2.449
2.574(22)
2.554(9)

|Xab|
0.176














RMS


0.091 (2.9 %)
0.074 (2.4 %)

RSD


0.030 (1.3 %)
0.030 (1.3 %)










Xxx
2.095





Xyy
2.449





Xzz - 3.544





ETA
0.078





Øz,a
88.48





Øa,bi
77.08





Øz,bi*
11.40














   








* The principal z-axis makes an angle of 11.40o with the external bisector of the C=N-C angle, and tilts toward N-C.

 








 








   







Table 2.  Nitrile 14N nqcc's in CH2NCN (MHz).  Calculation was made on the ro/ropt molecular structure.
 










Calc.
Expt. [1]
Expt. [2]
 








Xaa - 3.263 -
 3.264(33)
 - 3.254(8)

Xbb
0.800
0.813(19)
0.844(16)

Xcc
2.463
2.451(19)
2.410(16)

|Xab|
1.324














RMS


0.010 (0.45 %)
0.040 (1.8 %)

RSD


0.030 (1.3 %)
0.030 (1.3 %)










Xxx
1.194





Xyy
2.463





Xzz - 3.657





ETA
0.347





Øz,a
16.55





Øa,CN
13.68





Øz,CN
  2.87















 








 




Table 3.  CH2NCN Molecular structure parameters, ro [5] / ropt (Å and degrees).  
* MP2/6-31G(d,p) ropt with bond length correction, r = 1.001 x ropt  [6].
 







C(1)=N
1.269(10)



N-C(2)
1.372(10)



C(2)N
1.160(10)



C(1)Hc
1.088 *



C(1)Ht
1.083 *



C(1)=N-C(2)
116.6(10)



N-C(2)N
174.9(10)



HC(1)H
118.55 *



N-CHt
117.48 *



 








 








[1] M.Winnewisser, B.P.Winnewisser, and C.Wentrup, J.Mol.Spectrosc. 105,193(1984).

[2] W.H.Stolze, D.H.Sutter, and C.Wentrup, Z.Naturforsch. 44a,291(1989).

[3] B.Bak, O.J.Nielsen, and H.Svanholt, Chem.Phys.Lett. 59,330(1978).

[4] B.Bak and H.Svanholt, Chem.Phys.Lett. 66,387(1979).

[5] B.Bak and H.Svanholt, Chem.Phys.Lett. 75,528(1980).

[6] J.Demaison and G.Wlodarczak, Struct.Chem. 5,57(1994).

 








 








CH2NH





 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 28 May 2006