CH2F-CHFCl




 









Chlorine


Nuclear Quadrupole Coupling Constants

in 1-Chloro-1,2-Difluoroethane

 







 
 
Calculations of the chlorine nqcc tensors in three possible conformers of 1-chloro-1,2-difluoroethane shown below were made on approximate equilibrium structures given by MP2/aug-cc-pVTZ optimization with ~re CCl, C-C, and CF bond lengths.  (Also, see Calculation of Nuclear Quadrupole Coupling Constants on Approximate Equilibrium Structures: Ethanes.)  Relative energies shown below are energies calculated at the B1LYP/TZV(3df,2p) level of theory.
 
 
I.  E = 0 II.  E = 4.3 kJ/mole III.  E = 7.3 kJ/mole
 
The calculated nqcc tensors are given in Tables 1 and 2.  Structure parameters are given in Table 3.  Rotational constants and dipole moments (given by B1LYP/TZV(3df,2p) calculation) are given in Tables 4 and 5.
 
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.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
RSD is the calibration residual standard deviation of the B1LYP/TZV(3df,2p) model for calculation of the chlorine nqcc's.
 
 
   






Table 1. Calculated 35Cl nqcc's in Conformers I, II, and III of CH2F-CHFCl (MHz).  
   







Conf. I
Conf. II
Conf. III
   





Xaa - 55.35   4.40 - 20.33
Xbb 23.38 - 34.84 - 3.27
Xcc 31.97 30.43 23.60
Xab 31.25 - 45.30 - 48.70
Xac 21.91 - 15.82 - 27.70
Xbc - 6.39 - 21.55 - 19.67
 
RSD 0.49 (1.1 %) 0.49 (1.1 %) 0.49 (1.1 %)
 
Xxx 33.86 33.66 33.73
Xyy 37.42 37.91 39.38
Xzz - 71.28 - 71.57 - 73.11
ETA 0.050 0.059 0.077
Øz,CCl 0.78 1.00 0.58
 

 
 
   






Table 2. Calculated 37Cl nqcc's in Conformers I, II, and III of CH2F-CHFCl (MHz).  
   







Conf. I
Conf. II
Conf. III
   





Xaa - 44.02   0.76 - 17.78
Xbb 18.82 - 24.81 - 0.92
Xcc 25.20 24.05 18.70
Xab 24.13 - 36.78 - 38.10
Xac 17.30 - 13.03 - 22.07
Xbc - 4.90 - 16.41 - 14.94
 
RSD 0.44 (1.1 %) 0.44 (1.1 %) 0.44 (1.1 %)
 
Xxx 26.68 26.53 26.58
Xyy 29.49 29.88 31.04
Xzz - 56.18 - 56.41 - 57.62
ETA 0.050 0.059 0.077
Øz,CCl 0.78 1.00 0.58
 
 
 
Table 3.  Conformers I, II, and III of CH2F-CHFCl.  Heavy atom structure parameters (Å and degrees).  Complete structures are given here in Z-matrix format.
 
Conf. I Conf. II Conf. III
C(1)Cl 1.7706 1.7632 1.7663
C(1)F 1.3579 1.3638 1.3603
C(1)C(2) 1.5059 1.5101 1.5064
C(2)F 1.3766 1.3732 1.3698
C(2)C(1)Cl 108.12 111.14 111.33
FC(1)Cl 109.38 109.41 109.14
C(1)C(2)F 108.72 109.19 110.86
ClC(1)C(2)F 174.88 - 66.43   57.65

 
 
Table 4.  Conformers I, II, and III of CH2F-CHF35Cl.  Equilibrium Rotational Constants (MHz) and Dipole Moments (D).
Conf. I Conf. II Conf. III
A 7734.54 4976.96 5292.40
B 2399.55 3254.62 3190.07
C 1929.59 2091.66 2393.35
 
|mua| 0.31 0.75 0.58
|mub| 1.45 1.14 0.32
|muc| 0.37 0.17 2.87
mutot 1.52 1.37 2.94
 
 
Table 5.  Conformers I, II, and III of CH2F-CHF37Cl.  Equilibrium Rotational Constants (MHz) and Dipole Moments (D).
Conf. I Conf. II Conf. III
A 7703.75 4892.33 5261.70
B 2339.82 3207.12 3117.46
C 1888.94 2057.23 2346.33
 
|mua| 0.33 0.79 0.59
|mub| 1.44 1.11 0.31
|muc| 0.37 0.17 2.87
mutot 1.52 1.37 2.94

 







 
CHF2-CHFCl CHF2-CH2Cl CHF2-CF2Cl CH2F-CF2Cl
CF3-CF2Cl
Calculation of Nuclear Quadrupole Coupling Constants on Approximate Equilibrium Structures: Ethanes
 

 








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Last Modified 17 Dec 2009