CF2Br-CH=CH2
































 









Bromine


Nuclear Quadrupole Coupling Constants

in gauche-3-Bromo-3,3-Difluoropropene

 








 

 





Bromine nqcc tensors in g-3-Bromo-3,3-Difluoropropene were determined by Langridge, et al. [1].

 








Calculation of the nqcc tensor was made here on molecular structures given by MP2/aug-cc-pVTZ(G03) optimization; and on this same structures but with approximate equilibrium (~re) C-C, C=C, and CBr bond lengths.  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.  Øz,CBr (degrees) is the angle between the z-principal axis and the CBr bond direction.  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 nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's.

 








 








   







Table 1.  79Br nqcc's in g-CF2Br-CH=CH2 (MHz).  

 







Calc (1) was made on the MP2/aug-cc-pVTZ(G03) optimized molecular structure.

Calc (2) was made on this same structure but with ~re C-C, C=C, and CBr bond lengths.

 









Calc (1)
Calc (2)
Expt. [1]
   







Xaa
481.09
482.02
477.5173(42)

Xbb - 200.60 - 201.93 - 199.5456(56)

Xcc - 280.49 - 280.09 - 277.9717(37)

|Xab|
255.32
252.34
254.96(12)

|Xac|
  25.48
  25.78
  24.1(14)

|Xbc|
    7.44
    7.27
    8.40(40)

 







RMS
2.60 (0.82 %)
3.19 (1.00 %)



RSD
1.58 (0.39 %)
1.58 (0.39 %)



 







Xxx - 285.84 - 285.26 - 284.833(94)

Xyy - 281.11 - 280.63 - 278.73(13)

Xzz
566.94
565.89
563.56(11)

ETA - 0.0083 - 0.0082 - 0.0108(3)

Øz,CBr
0.88
0.95



 
 






 








* The algabraic sign of the product XabXacXbc is positive.

 








 








   







Table 2.  81Br nqcc's in g-CF2Br-CH=CH2 (MHz).  

 







Calc (1) was made on the MP2/aug-cc-pVTZ(G03) optimized molecular structure.

Calc (2) was made on this same structure but with ~re C-C, C=C, and CBr bond lengths.

 









Calc (1)
Calc (2)
Expt. [1]
   







Xaa
403.38
404.12
400.3604(44)

Xbb - 169.03 - 170.11 - 168.1386(60)

Xcc - 234.35 - 234.01 - 232.2218(40)

|Xab|
211.38
208.92
211.078(77)

|Xac|
  21.23
  21.48
  20.47(93)

|Xbc|
    6.12
    5.97
    6.77(23)

 







RMS
1.81 (0.68 %)
2.66 (1.00 %)



RSD
1.38 (0.40 %)
1.38 (0.40 %)



 
 






 








* The algabraic sign of the product XabXacXbc is positive.

 








 












Table 3.  g-3-Bromo-3,3-Difluoropropene.  Selected structure parameters (Å and degrees).  Complete structures are given here in Z.matrix format.
 


Point Group C1 r (1) = MP2/aug-cc-pVTZ(G03) opt.

r (2) = r (1) but with ~re C-C, C=C, and CBr bond lengths.





  r (1)   r (2)



CBr 1.9399 1.9479
C(3)C(2) 1.4866 1.4861
C(2)C(4) 1.3317 1.3280
BrC(3)C(2) 110.37 110.37
C(3)C(2)C(4) 122.63 122.63
BrC(3)C(2)C(4) 115.42 115.42
 



 








 













Table 4.  g-3-Bromo-3,3-Difluoropropene.  Rotational constants (MHz).  79Br species.
 




r (1) = MP2/aug-cc-pVTZ(G03) opt.

r (2) = r (1) but with ~re C-C, C=C, and CBr bond lengths.







  r (1)   r (2)     Expt. [1]






A 3658.58 3676.77 3642.70968(26)

B 1606.24 1602.32 1598.21758(12)

C 1419.96 1416.72 1410.15643(12)
 
 



 








 








[1] J.D.Langridge, B.E.Long, and S.A.Cooke, J.Mol.Struct. 1000,24(2011).

 








 








cis-3-Chloropropene gauche-3-Bromopropene



gauche-3-Chloropropene 2-Bromopropene



 








 








Table of Contents




Molecules/Bromine




 








 













gCF2BrCHCH2.html






Last Modified 23 July 2011