CHF2-CHFCl




 









Chlorine


Nuclear Quadrupole Coupling Constants

in 1-Chloro-1,2,2-Trifluoroethane

 







 
 
Calculations of the chlorine nqcc tensors in three possible conformers of 1-chloro-1,2,2-trifluoroethane 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 = 4.6 kJ/mole III.  E = 4.6 kJ/mole
 
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 CHF2-CHFCl (MHz).  
   







Conf. I
Conf. II
Conf. III
   





Xaa - 41.35   2.66 - 45.27
Xbb 10.34 - 19.50 10.32
Xcc 31.01 16.83 34.95
Xab 43.83 42.25 47.04
Xac 23.90 - 29.51 - 11.36
Xbc - 12.72 34.96   3.14
 
RSD 0.49 (1.1 %) 0.49 (1.1 %) 0.49 (1.1 %)
 
Xxx 35.17 34.62 33.73
Xyy 38.24 40.26 39.59
Xzz - 73.41 - 74.88 - 73.32
ETA 0.042 0.075 0.080
Øz,CCl 1.06 1.20 0.68
 

 
 
   






Table 2. Calculated 37Cl nqcc's in Conformers I, II, and III of CHF2-CHFCl (MHz).  
   







Conf. I
Conf. II
Conf. III
   





Xaa - 33.56 - 0.06 - 36.21
Xbb   9.07 - 13.74   8.74
Xcc 24.48 13.80 27.47
Xab 34.00 34.01 36.68
Xac 18.90 - 23.79 - 9.32
Xbc - 9.73 26.55   2.59
 
RSD 0.44 (1.1 %) 0.44 (1.1 %) 0.44 (1.1 %)
 
Xxx 27.72 27.28 26.58
Xyy 30.14 31.73 31.20
Xzz - 57.85 - 59.01 - 57.79
ETA 0.042 0.075 0.080
Øz,CCl 1.06 1.20 0.68
 
 
 
Table 3.  Conformers I, II, and III of CHF2-CHFCl.  Selected structure parameters (Å and degrees).  Complete structures are given here in Z-matrix format.
 
Conf. I Conf. II Conf. III
C(1)Cl 1.7586 1.7524 1.7621
C(1)F 1.3555 1.3594 1.3505
C(1)C(2) 1.5181 1.5201 1.5196
C(2)C(1)Cl 109.52 111.45 109.25
FC(1)Cl 109.71 110.25 110.19

 
 
Table 4.  Conformers I, II, and III of CHF2-CHF35Cl.  Equilibrium Rotational Constants (MHz) and Dipole Moments (D).
Conf. I Conf. II Conf. III
A 4260.30 3639.28 4681.73
B 2226.11 2356.07 1974.35
C 1528.46 1898.50 1733.39
 
|mua| 0.28 0.44 0.50
|mub| 0.16 0.80 0.40
|muc| 0.05 1.87 2.24
mutot 0.32 2.08 2.33
 
 
Table 5.  Conformers I, II, and III of CHF2-CHF37Cl.  Equilibrium Rotational Constants (MHz) and Dipole Moments (D).
Conf. I Conf. II Conf. III
A 4246.35 3600.58 4668.92
B 2169.42 2316.88 1926.38
C 1499.84 1863.72 1695.33
 
|mua| 0.28 0.47 0.51
|mub| 0.15 0.79 0.40
|muc| 0.05 1.86 2.23
mutot 0.32 2.08 2.33

 







 
CH2F-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