CH2=CH-CH=CHCl





 








 









Chlorine


Nuclear Quadrupole Coupling Constants


in 1-Chloro-1,3-butadiene


 








 








Microwave spectra of the cis and trans conformers of 1-chloro-1,3-butadiene were assigned by Karlsson et al. [1,2].

 









cis



trans












































Calculation of the Cl nqcc tensors was made here on the experimental structures of Karlsson et al. [1,2], and on approximate re structures given by MP2/aug-cc-pVTZ optimization with empirical correction of the C=C, C-C, anf CCl bond lengths.  Calculated and experimental [1] nqcc's for the cis conformer are compared in Table 1, experimetnal nqcc's for the trans conformer are given in Table 2.  Structure parameters are given in Table 3.

 








In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  ETA = (Xxx - Xyy)/Xzz.  Ø (degrees) is the angle between its subscripted parameters. 

RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation for the B1LYP/TZV(3df,2p) model for calculation of the chlorine efg's/nqcc's.


 








 







 
   








Table 1. Chlorine nqcc's in cis-CH2=CH-CH=CHCl (MHz).  Calculation was made on the rs [1] and approximate re structures.

   











Calc  rs
Calc  re
Expt. [1]
   








35Cl Xaa
- 4.19
- 2.69
- 2.62(28)


Xbb - 25.90 -
 27.42
 - 27.85(14)


Xcc
30.10
30.11
30.47


|Xab|
53.32
53.07



 









RMS
1.46 (7.2 %)
0.32 (1.6 %)




RSD
0.49 (1.1 %)
0.49 (1.1 %)



 









Xxx
39.37
39.43




Xyy
30.10
30.11




Xzz - 69.47 -
 69.54




ETA - 0.133 -
 0.134




Øz,a
50.75
51.56




Øa,CCl
51.82
52.11




Øz,CCl
  1.07
  0.55



   







37Cl Xaa
- 3.81
- 2.62




Xbb - 19.91 -
 21.11




Xcc
23.72
23.73




|Xab|
42.12
41.94



 









RSD
0.44 (1.1 %)
0.44 (1.1 %)



 









 








 








   








Table 2. Chlorine nqcc's in trans-CH2=CH-CH=CHCl (MHz).  Calculation was made on the rs/ro (see [2] for explanation) and approximate re structures.

   











Calc  rs/ro
Calc  re
Expt.
   








35Cl Xaa -
 53.65 -
 52.74




Xbb
22.88
22.23




Xcc
30.77
30.51




|Xab|
39.76
40.32



 









RSD
0.49 (1.1 %)
0.49 (1.1 %)



 









Xxx
39.80
39.80




Xyy
30.77
30.51




Xzz - 70.57 -
 70.31




ETA - 0.128 -
 0.132




Øz,a
23.05
23.54




Øa,CCl
23.30
23.26




Øz,CCl
  0.25
  0.28



   







37Cl Xaa -
 42.40 -
 41.67




Xbb
18.15
17.63




Xcc
24.25
24.04




|Xab|
31.23
31.68



 









RSD
0.44 (1.1 %)
0.44 (1.1 %)



 









 








 



Table 3.  1-Chloro-1,3-butadiene.  Heavy atom structure parameters (Å and degrees).  The complete re structures are given here in Z-matrix format.
 




cis
   rs [1]    re



CCl
 1.731(8)
 1.7249
C(2)=C(3)
 1.327(6)
 1.3370
C(3)--C(4) 1.449(13)
 1.4487
C(4)=C(5) 1.343(2)
 1.3386
ClC(2)=C(3)
 123.7(3)
 123.56
C(2)=C(3)--C(4) 126.5(3)
 126.07
C(3)--C(4)=C(5) 123.0(7)
 122.70
 

 







trans
 rs/ro [2]
    re



CCl
 1.737(4)
 1.7208
C(2)=C(3) 1.313(10)
 1.3355
C(3)--C(4) 1.439(6)
 1.4506
C(4)=C(5) 1.340(7)
 1.3380
ClC(2)=C(3) 123.5(7)
 122.84
C(2)=C(3)--C(4) 124.1(11)
 121.98
C(3)--C(4)=C(5) 124.8(10)
 123.32






 








 








[1] F.Karlsson and Z.Smith, J.Mol.Spectrosc. 81,327(1980).

[2] P.Cederbalk and F.Karlsson, Acta Chem. Scand. A 34,541(1980).

 








 








CH2=CHCl 2-Chloro-1,3-butadiene



 








 








Table of Contents




Molecules/Chlorine




 








 













CH2CHCHCHCl.html






Last Modified 18 June 2014