HCC-CH2-CN































 









Nitrogen


Nuclear Quadrupole Coupling Constants


in 3-Butynenitrile (propargl cyanide)


 








 

 





Calculation of the nitrogen nqcc's in propargl cyanide was made on a structure given by MP2/aug-cc-pVTZ(G03) optimization with empirical correction for the bond lengths (~ re).  These are compared wtih the experimental nqcc's of Jäger et al. [1] in Table 1.  Structure parameters are given in Table 2, rotational constants and dipole moments in Table 3.











In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor; 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 inertial axes nqcc's (percent of the average experimental magnitude).  RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's, which may be taken as a conservative estimate of the uncertainty in the calculated nqcc's.

 








 








   






Table 1.  Nitrogen nqcc's in HCC-CH2-CN (MHz).  Calculation was made on the ~ re structure.

   








Calc.
Expt. [1]

 






14N Xaa - 2.228 - 2.2558(22)


Xbb
0.178
0.2102(29)

  Xcc
2.050
2.0456(29)


|Xab|
3.008



 







RMS
0.024 (1.6 %)




RSD
0.030 (1.3 %)



 







Xxx
2.215




Xyy
2.050




Xzz - 4.265




ETA - 0.039




Øz,a
34.10




Øa,CN
34.11




Øz,CN
  0.02



 







 








 











Table 2.  HCC-CH2-CN  Selected structure parameters, ~ re (Å and degrees).  The complete strcucture is given here in Z-matrix format.
 

Angles are exaggerated. C(1)C(7) 1.4652
C(7)N 1.1555
C(1)C(4) 1.4617
C(4)C(5) 1.2028
C(5)H 1.0620
C(1)C(7)N 179.27
C(1)C(4)C(5) 179.63
Click on image to enlarge. C(4)C(5)H 179.64
 



 












Table 3.  HCC-CH2-CN  Rotational Constants [2] and Dipole Moments [3].






        ~ re    Expt. [2,3]





A /MHz
     19 496.2 19 820.4418(4)

B /MHz
       2 935.4   2 909.5993(1)

C /MHz
       2 592.0   2 573.2246(1)





|µa| /D
       2.97
   3.23(5)

|µb| /D
       2.27
   2.34(2)

|µtot| /D       3.73
   3.99(5)



 








 








[1] W.Jäger, H.Krause, H.Mäder, and M.C.L.Gerry, J.Mol.Spectrosc. 143,50(1990).

[2] D.McNaughton, N.G.Romeril, M.F.Lappert, and H.W.Kroto, J.Mol.Spectrosc. 132,407(1988).

[3] J.Demaison, I.Pohl, and H.D.Rudolph, J.Mol.Spectrosc. 114,210(1985).

 








 








CH3CN FCH2CN ClCH2CN CH2(CN)2

Calculation of Cl and N nqcc's on approximate equilibrium structures of F, Cl - Acetoniriles.

 








 








Table of Contents




Molecules/Nitrogen




 








 













HCCCH2CN.html






Last Modified 21 Oct 2007