CF3-CHFBr




















 

















Bromine


Nuclear Quadrupole Coupling Constants

in 2-Bromo-1,1,1,2-Tetrafluoroethane


 








 








 








Bromine nqcc's in 2-bromo-1,1,1,2-tetrafluoroethane were determined by Isert, et al. [1].  Calculation of the nqcc's was made here on optimized molecular structures at MP2/6-311+G(3df,3pd) and  MP2/aug-cc-pVTZ levels of theory.  These calculated nqcc's are compared with the experimental values in Tables 1 and 2.  Structure parameters are given in Table 3, rotational constants in Table 4.


 








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.  (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.  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 of the B1LYP/TZV(3df,3p) model for calculation of the bromine nqcc's.

 








 








 
   








Table 1.  79Br nqcc's in CF3CHFBr (MHz).  Calculation was made on (1) MP2/6-311+G(3df,3pd) and (2) MP2/aug-cc-pVTZ optimized structures.
   










Calc. (1)

Calc. (2)
Expt. [1]
   








Xaa
405.52
400.71
399.223(3)


Xbb - 157.18 - 153.28 -
154.542(2)


Xcc -
248.34 - 247.43 -
244.682(2)


Xab * -
305.93 -
308.45 -
305.54(3)


Xac *
216.39
217.05 -
218.56(5)


Xbc *
- 84.13

- 85.29

  85.97(3)


 







RMS
4.47 (1.68 %)
1.95 (0.73 %)



RSD
1.58 (0.39 %)
1.58 (0.39 %)



 







Xxx - 287.63
- 286.68 -
286.11(3)


Xyy - 315.39
- 315.49 -
313.77(4)


Xzz
603.02
602.17
599.88(3)


ETA
0.0460
0.0478
0.04611(8)


z,CBr
1.43

1.38




 








 








* The algebraic signs of the individual off-diagonal components are irrelevant.  The product XabXacXbc matters and is positive for both calculated and experimental.

 








 








   








Table 2.  81Br nqcc's in CF3CHFBr (MHz).  Calculation was made on (1) MP2/6-311+G(3df,3pd) and (2) MP2/aug-cc-pVTZ optimized structures.
   










Calc. (1)

Calc. (2)
Expt. [1]
   








Xaa
339.75
335.75
334.477(3)


Xbb - 132.26 - 129.02 -
130.067(2)


Xcc -
207.50 - 206.73 -
204.411(2)


Xab * -
254.74 -
256.84 -
254.35(2)


Xac *
180.90
181.45 -
182.72(3)


Xbc *
- 69.95

- 70.91

  71.43(3)


 







RMS
3.75 (1.68 %)
1.65 (0.74 %)



RSD
1.38 (0.40 %)
1.38 (0.40 %)



 








 








* The algebraic signs of the individual off-diagonal components are irrelevant.  The product XabXacXbc matters and is positive for both calculated and experimental.

 








 













Table 3.  CF3CHFBr Structure Parameters ( and degrees).  (1) MP2/6-311+G(3df,3pd) and (2) MP2/aug-cc-pVTZ optimized structures.






 Br
 C,1,B1
 C,2,B2,1,A1
 H,2,B3,1,A2,3,D1,0
 F,2,B4,1,A3,3,D2,0
 F,3,B5,2,A4,1,D3,0
 F,3,B6,2,A5,1,D4,0
 F,3,B7,2,A6,1,D5,0
 







   Structure (1)

   Structure (2)






 B1=1.91524675
 B2=1.52782494
 B3=1.08629076
 B4=1.35453673
 B5=1.33084919
 B6=1.32490608
 B7=1.3343232
 A1=111.0781845
 A2=108.1760993
 A3=110.46539304
 A4=110.23712118
 A5=112.07373307
 A6=108.72118469
 D1=-119.95465226
 D2=119.8438868
 D3=-61.37999784
 D4=60.35491092
 D5=-179.87197098

 B1=1.90823437
 B2=1.52711564
 B3=1.08675369
 B4=1.35841883
 B5=1.33507736
 B6=1.32894201
 B7=1.33875211
 A1=110.74941827
 A2=108.18554230
 A3=110.44597470
 A4=110.21989739
 A5=112.20755872
 A6=108.91531368
 D1=-119.83188564
 D2=119.96104263
 D3=-61.62671383
 D4=60.02688655
 D5=179.89958396










































 













Table 4.  CF3CHFBr Rotational Constants (MHz), Parent. Calc (1) MP2/6-311+G(3df,3pd) and Calc (2) MP2/aug-cc-pVTZ optimized structures.







Calc (1)
Calc (2)   Expt. [1]






A  3075.
 3058.
3063.0485(1)

B  1168.
 1174.
1163.59326(6)

C  1004.
 1008.
1000.20122(5)


 








 


















[1] J.E.Isert, F.E.Marshall, and G.S.Grubbs, Abstract WI09, 74th ISMS, Champaign-Urbana, Illinois, 2019.


 








 








CH3Br CH3CH2Br CHBrF2 CH2BrF

CH2Br2 HCCBr BrCN
CF3Br

CH3-CHFCl CH2BrCl
CH3CHFBr
CF3-CF2Br


 








 








Table of Contents




Molecules/Bromine




 








 













CF3CHFBr.html






Last Modified 29 Aug 2019