C(H)Cl=C(H)CCH




























 









Chlorine


Nuclear Quadrupole Coupling Constants


in t-1-Chlorobuten-3-yne


 








 








 








Calculation of the chlorine nqcc's in t-1-chlorobuten-3-yne was made on an approximate equilibrium structure derived here by MP2/aug-cc-pVTZ optimization with empirically corrected bond lengths.  These nqcc's are compared with the available experimental values [1] in Table 1.  Structure parameters are given in Table 2, rotational constants 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.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.

RSD is the calibration residual standard deviation for the B1LYP/TZV(3df,2p) model for calculation of the chlorine nqcc's, which may be taken as an estimate of the uncertainty in the calculated coupling constants.

 








 








   







Table 1. Chlorine nqcc's in t-1-Chlorobuten-3-yne (MHz).
   










Calc.
Expt. [1]
   







35Cl Xaa - 63.55 - 63.6(4)



Xbb
33.45





Xcc
30.10




|Xab|
27.34



 







RSD
0.49 (1.1 %)



 







Xxx
40.64




Xyy
30.10




Xzz - 70.74




ETA - 0.149




Øz,a
14.72




Øa,CCl
14.53




Øz,CCl
  0.19



   





37Cl Xaa - 50.09 -
51.0(4)



Xbb
26.36





Xcc
23.73




|Xab|
21.57



 







RSD
0.44 (1.1 %)



 







 








 








 

Table 2.  t-1-Chlorobuten-3-yne   Heavy atom structure parameters (Å and degrees).  Complete structure is given here in Z-matix format.
 


Parameter
 reapprox


C(1)Cl 1.7167
C(1)=C(2) 1.3366
C(2)C(6) 1.4220
C(6)C(7) 1.2069
C(2)C(1)Cl 122.22
C(1)C(2)C(6)
120.48


 








 













Table 3.  t-1-Chlorobuten-3-yne  Rotational Constants (MHz).   Calc is on the reapprox molecular structure.
 







  Calc.
  Expt. [1]







A
48436.8
48604(41)


B
  1514.9
  1509.612(2)


C
  1469.0
  1463.459(2)



 









 









[1] F.Karlsson and R.Vestin, Acta Chem. Scand. 27,3033(1973).


 








 








CH2=C=C=CHCl
2-Chlorobuten-3-yne 4-Chlorobuten-3-yne


 








 








Table of Contents




Molecules/Chlorine




 








 













t1Clbuten3yne.html






Last Modified 29 Nov 2011