CF2=CHCl



























 






Chlorine


Nuclear Quadrupole Coupling Constants


in 1-Chloro-2,2-difluoroethylene


 








 








 








The complete 35Cl nqcc tensor in 1-chloro-2,2-difluoroethylene was measured by Stone and Flygare [1]; diagonal 35Cl and 37Cl were subsequently determined by Leal et al. [2]; and 35Cl, 37Cl, and D nqcc tensors were determined by Leung et al [3].  The latter also obtained an average (ravg) from a fit to the moments of inertia Ia and Ib.  Chandra [3] derived a ground state effective ro structure.

 








Calculation of the chlorine and deuterium nqcc's was made on the average structure of Leung et al., and on an approximate equilibrium structure derived by MP2/aug-cc-pVTZ optimization with empirically corrected bond lengths.  These calculated nqcc's are compared with the experimental values [3] in Tables 1 - 3.  Structure parameters are given in Table 4.

 








In Tables 1 - 3, 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, and of the B3LYP/6-31G(df,3p) model for the deuterium efg's/nqcc's.

 








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.  ETA = (Xxx - Xyy)/Xzz.  Ø (degrees) is the angle between its subscripted parameters.

 








 







 
   








Table 1. Chlorine nqcc's in CF2=CHCl (MHz).  Calculation was made on the average molecular structure of Leung [3], and on approximate re structure.
   











Calc /ravg
Calc /re
Expt. [3]
   








35Cl Xaa - 56.93
 -
 54.83
 -
 54.8923(48)


Xbb
20.89
18.43
18.2356(57)


Xcc
36.04
36.40
36.6567(56)


|Xab|
45.45
46,85
47.02(13)

 









RMS
1.97 (5.4 %)
0.19 (0.51 %)




RSD
0.49 (1.1 %)
0.49 (1.1 %)



 









Xxx
41.81
41.27




Xyy
36.04
36.40




Xzz - 77.85
 - 77.67




ETA - 0.074
 - 0.063




Øz,a
24.71
25.99




Øa,CCl
26.52
26.64




Øz,CCl
  1.80
  0.65



 








37Cl Xaa -
 44.88
 -
 43.22
 -
 43.2687(56)


Xbb
16.47
14.53
14.3688(66)


Xcc
28.41
28.69
28.8999(63)


|Xab|
35.81
36.92
36.77(50)


 








RMS
1.56 (5.4 %)
0.15 (0.54 %)




RSD
0.44 (1.1 %)
0.44 (1.1 %)



 









 








 








   








Table 2. Chlorine and Deuterium nqcc's in CF2=CD35Cl (MHz and kHz respectively).  Calculation was made on the average molecular structure of Leung [3], and on approximate re structure.
   











Calc /ravg
Calc /re
Expt. [3]
   








35Cl Xaa - 56.56
 -
 54.58
 -
 54.7054(10)


Xbb
20.52
18.18
18.0667(13)


Xcc
36.04
36.40
36.6387(11)


|Xab|
45.76
47.05
46.860(13)

 









RMS
1.81 (5.0 %)
0.17 (0.45 %)




RSD
0.49 (1.1 %)
0.49 (1.1 %)



 








  2H Xaa
- 80.5
- 86.3
- 85.7(27)


Xbb
185.8
197.9
192.5(19)


Xcc - 105.3
 -
 111.6
 -
 106.9(14)


|Xab|
  27.0
    4.3




 








RMS
5.0 (3.9 %)
4.1 (3.2 %)




RSD
1.1 (0.86 %)
1.1 (0.86 %)



   








Xxx
- 83.2
- 86.3




Xyy -
 105.3
 -
 111.6




Xzz
188.5
197.9




ETA
0.117
0.127



  Øz,a
95.74
89.13




Øa,CD
96.36
88.57




Øz,CD
  0.62
  0.56



 









 








 








   








Table 2. Chlorine and Deuterium nqcc's in CF2=CD37Cl (MHz and kHz respectively).  Calculation was made on the average molecular structure of Leung [3], and on approximate re structure.
   











Calc /ravg
Calc /re
Expt. [3]
   








37Cl Xaa - 44.62
 -
 43.06
 -
 43.1558(11)


Xbb
16.22
14.37
14.2807(12)


Xcc
28.40
28.69
28.8751(11)


|Xab|
36.03
37.05
36.898(12)

 









RMS
1.43 (5.0 %)
0.13 (0.45 %)




RSD
0.44 (1.1 %)
0.44 (1.1 %)



 








  2H Xaa
- 80.5
- 86.3
- 85.2(27)


Xbb
185.8
197.9
192.3(19)


Xcc - 105.3
 -
 111.6
 -
 107.1(14)


|Xab|
  26.9
    4.5




 








RMS
4.7 (3.7 %)
4.2 (3.2 %)




RSD
1.1 (0.86 %)
1.1 (0.86 %)



 









 








 


Table 4.  CF2=CHCl Molecular structure parameters (Å and degrees).  FCl is cis with respect to Cl, FH is cis with respect to H.
 




ravg [3] approx re





CCl 1.7311(69)
 1.7105

CH 1.0826(30)
 1.0754

C=C 1.3029(87)
 1.3236

CFCl 1.3295(33)
 1.3059

CFH 1.3211(87)
 1.3126

C=CCl 121.3(11)
 121.61

C=CH 128.31(83)
 120.16

C=CFCl 126.14(24)
 125.67

C=CFH 123.44(24)
 123.20

FCF
111.13


 








 








[1] R.G.Stone and W.H.Flygare, J.Chem.Phys. 49,1943(1968): Xaa = -55.05(10),  Xbb = 18.29(8), Xcc = 36.76(10), |Xab| = 46.3(40) MHz.

[2] L.A.Leal, J.C.López, J.L.Alonso, and A.Guarnieri, Z.Naturforsch. 48a, 514(1993): For 35Cl, Xaa = -54.81(8),  Xbb = 18.18(4), Xcc = 36.63(6) MHz; and for 37Cl, Xaa = -42.9(2),  Xbb = 14.2(1), Xcc = 28.7(1) MHz

[3] H.O.Leung, M.D.Marshall, J.P.Messinger, G.S.Knowlton, K.M.Sundheim, J.C.Cheung-Lau, J.Mol.Spectrosc. 305,25(2014).

 








S.Chandra, J.Phys.Chem. 71,1927(1967): ro structure.

D.R.Jenkins and T.M.Sugden, Trans.Farad.Soc.55,1473(1959):  Xaa = -51.7(13),  Xbb = 18.2(10), Xcc = 33.5(8) MHz.

 








 








CH2CHCl c-CHFCHCl CH2CCl2 c-ClHCCHCl

 








 








Table of Contents




Molecules/Chlorine




 








 













CF2CHCl.html






Last Modified 3 Oct 2014