CH3C(=O)CN




 








Nitrogen


Nuclear Quadrupole Coupling Constants


in Acetyl Cyanide


 








 








 








Calculation was made of the nitrogen nqcc's in acetylyl cyanide on an approximate equilibrium structure ~re,  derived here by MP2/aug-cc-pVTZ(G03) optimization with empirically corrected bond lengths.  These calculated nqcc's are compared with the experimental values [1] in Table 1.  Structure parameters are given in Z-matrix format 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.  (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.  Nitrogen nqcc's in CH3C(=O)CN (MHz).  Calculation was made on the ~re structure.
   










Calc.
Expt. [1]
   







14N Xaa - 4.649 - 4.5716(11)


Xbb
1.719
1.8169(13)


Xcc
2.931
2.7547(13)


|Xab|
0.532
0.52(10) *

 







RMS
0.125 (4.1 %)




RSD
0.030 (1.3 %)



 







Xxx
1.762
1.860(16)


Xyy
2.931
2.7547(13)


Xzz - 4.694 - 4.614(16)


ETA
0.249
0.1942(36)


z,a
4.75




a,CN
5.23




z,CN
0.48



 






   








* Ab initio value.

 








 










Table 2.  CH3C(=O)CN Molecular structure parameters ( and degrees).
 
 C
 C, 1, R2
 O, 2, R3, 1, A3
 C, 2, R4, 1, A4, 3, 180., 0
 H, 4, R5, 2, A5, 1, 180., 0
 H, 4, R6, 2, A6, 1,  D, 0
 H, 4, R6, 2, A6, 1, -D, 0
 N, 1, R7, 2, A7, 4,  0., 0
      Variables:
 R2 = 1.4794
 R3 = 1.2075
 R4 = 1.4944
 R5 = 1.08551034
 R6 = 1.09055853
 R7 = 1.1575
 A3 = 119.78646324
 A4 = 114.75083739
 A5 = 109.73388275
 A6 = 109.32934103
 A7 = 178.87999263
 D   = 58.53861195
 


 








[1] A.Kraśnicki, L.Pszczłkowski, and Z.Kisiel, J.Mol.Spectrosc. 260,57(2010).

 








F.Scappini and H.Dreizler, Z.Naturforsch. 31a,840(1976): Xaa = -4.34(7), Xbb = 2.03(31), Xcc = 2.31(31) MHz.

G.K.Pandey, M.Andolfatto, and H.Dreizler, Z.Naturforsch. 32a,1301(1977):  ro and rs structures; and nqcc's in CH2DC(=O)CN.

 









 








HC(=O)CN CH3C(=O)Cl HC(=O)Cl CH3CDO

H2C=O O=CCl2 O=CBr2 CH2(CN)-C(=O)H

 








 








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Molecules/Nitrogen




 








 













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Last Modified 17 Dec 2009