O=C(CN)2





 








Nitrogen

Nuclear Quadrupole Coupling Constants


in Carbonyl Cyanide


 








 








Calculation of the 14N nqcc's in O=C(CN)2 were made on the re strcuture of Demaison et al. [1].  These are compared with the experimental values of Lees [2] in Table 1.  Structure parameters are given in Table 2.

 








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.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the 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 standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's.

 








 








   






Table 1.  Nitrogen nqcc's in O=C(CN)2 (MHz).
   









Calc.
Expt. [2]
   






14N Xaa - 3.002 -
 2.846(24)


Xbb - 0.019
0.045(16)


Xcc
3.021
2.801(32)


Xab ± 2.992



   






RMS
0.160 (8.4 %)




RSD
0.030 (1.3 %)




 






Xxx
1.832




Xyy
3.021




Xzz - 4.853




ETA
0.245




Øz,a
58.25




Øa,CN
58.14




Øz,CN
  0.11



 






   








 













Table 2.  Molecular structure parameters, re [1] (Å and degrees).







OC 1.204


CC 1.461


CN 1.159


OCC 122.63


CCN 179.23







CN tilts outward.


 








 








[1] J.Demaison, G.Wlodarczak, H.Rück, K.H.Wiedenmann, and H.D.Rudolph, J.Mol.Struct. 376,399(1996).

[2] R.M.Lees, Can.J.Phys. 49,367(1971).

 








 








S(CN)2 H2C(CN)2 H2C=C(CN)2 CH3C(=O)CN

H2C=O O=CCl2 O=CBr2 HC(=O)CN

 








The B3PW91/6-311+G(df,pd) model for calculation of the electric field gradients appears to not perform well for X-C(=O)CN type molecules.

 








 








Table of Contents




Molecules/Nitrogen




 








 













OCCNCN.html






Last Modified 14 Jan 2004