O=C=C(H)CN




 








Nitrogen


Nuclear Quadrupole Coupling Constants


in Cyanoketene


 








 








 








Nitrogen nqcc's in cyanoketene a mixed rs/ro structure was reported by Hahn, et al. [1].  Calculation of the nqcc's was made on this structure, and on an approximate re structure given by MP2/aug-cc-pVTZ optimization with empirically corrected bond lengths.  These calculated nqcc's are compared with the experimental values 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 stand deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's.

 








 








 








Table 1.  14N nqcc's in Cyanoketene (MHz).  Calculation was made on the rs/ro and approximate re structures.

 










Calc / rs/ro
Calc / re
Expt. [1]
 








Xaa - 2.437 -
2.465
- 2.461(13)

Xbb
1.290
1.316

1.220(12)

Xcc
1.147
1.149

1.241(18)

|Xab|
2.937
2.921













RMS
0.069 (4.2 %)
0.077 (4.7 %)




RSD
0.030 (1.3 %)
0.030 (1.3 %)












Xxx
2.905
2.905

2.709(44) *

Xyy
1.147
1.149

1.241(18)

Xzz - 4.052 -
4.054
- 3.950(82)

ETA - 0.434 -
0.433
- 0.372(15)

Øz,a
28.80
28.54




Øa,CN
28.14
28.32

28.22

Øz,CN
  0.66
  0.22













   








* Bond axis nqcc's on rs/ro structure [1].


 












Table 2. Structure parameters, rs/ro [1] and approximate re (Å and degrees).
 





  rs/ro     re





NC 1.158(1)1.1581

C-C 1.434(6)1.4174

CH 1.059(34)1.0791

C=C 1.334(12)1.3261

OC 1.148(8)1.1505

NC-C 178.1(5)178.85

HC=C 119.9(2)117.70

C=C-C 118.5(12)120.54

O=C=C 176.5(15)179.02



 








 








[1] M.Hahn, H.-K.Bodenseh, and M.Ferner, J.Mol.Spectrosc. 223,138(2004).

 








 








Ketene Chloroketene Bromoketene



 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 9 Dec 2011