CF2=CHBr
























 






Bromine


Nuclear Quadrupole Coupling Constants


in 1-Bromo-2,2-Difluoroethylene


 








 








Bromine nqcc's in 1-bromo-2,2-difluoroethylene were determined by Oldag and Sutter [1].

 








Calculation of the Br nqcc's was made here on a molecular structure given by MP2/aug-cc-pVTZ optimization (ropt) and on this same structure but with approximate equilibrium bond lengths (re).











Calculated and experimental nqcc's are compared in Tables 1 and 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 measn square difference between calculated and experimental diagonal nqcc's.  RSD is the residual standard deviation of calibration of the B1LYP/TZV(3df,3p) model for calculation of the efg's/nqcc's.











 








 








Table 1.  79Br nqcc's in CF2=CHBr (MHz).  Calculation was made on ropt and re structures.
 










Calc /ropt
Calc /re
Expt. [1]
 








Xaa
453.93
458.56
453.959(20)

Xbb - 161.75 -
 163.43
 - 160.648(11)

Xcc - 292.18 -
 295.13
 - 293.311(11)

|Xab|
354.56
352.61
354.369(24)










RMS
0.91 (0.30 %)
3.28 (1.1 %)



RSD
1.58 (0.39 %)
1.58 (0.39 %)












Xxx - 323.46 -
 322.59
 - 322.400(14)

Xyy - 292.18 -
 295.13
 - 293.311(11)

Xzz
615.64
617.73
615.711(20)

ETA - 0.0508 -
 0.0444



Øz,a
24.52
24.29
24.534(2)

Øa,CBr
25.27
25.03



Øz,CBr
  0.76
  0.74













 








 








 








Table 2.  81Br nqcc's in CF2=CHBr (MHz).  Calculation was made on ropt and re structures.
 










Calc /ropt
Calc /re
Expt. [1]










Xaa
379.25
383.12
379.262(24)

Xbb -
 135.15
 -
 136.55
 - 134.213(13)

Xcc -
 244.10
 -
 246.57
 - 245.049(13)

|Xab|
296.22
294.59
296.094(34)










RMS
0.76 (0.30 %)
2.75 (1.1 %)



RSD
1.38 (0.40 %)
1.38 (0.40 %)













 







 



Table 3. CF2=CHBr   MP2/aug-cc-pVTZ optimized structure parameters (Å and degrees).  Approximate equilibrium bond lengths are given in parentheses.






 Br
 C,1,R2
 H,2,R3,1,A3
 C,2,R4,1,A4,3,180.,0
 F,4,R5,2,A5,1,180.,0
 F,4,R6,2,A6,1,0.,0


 R2=1.85749293       (1.8663)
 R3=1.07551848
 R4=1.32632442       (1.3227)
 R5=1.3183466         (1.3127)
 R6=1.31156598       (1.2852)
 A3=118.32735116
 A4=121.8194842
 A5=123.35268958
 A6=125.83406858






 








 








[1] F.Oldag and D.H.Sutter, Z.Naturforsch. 46a,513(1991).

 








 








H2C=CHBr c-BrHC=CHF t-BrHC=CHF H2C=CFBr

H2C=CHCl c-ClHC=CHF t-ClHC=CHF


 








 








Table of Contents




Molecules/Bromine




 








 













CF2CHBr.html






Last Modified 21 Dec 2015