BrClCH2


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Chlorine and Bromine


Nuclear Quadrupole Coupling Constants


in Bromochloromethane


 








 








 








Chlorine and bromine nqcc's in bromochloromethane were measured by Niide and Ohkoshi [1], who also derived  an effective ro molecular structure. Calculation of the nqcc's was made here on this structure, and on an ~re structure given by MP2/aug-cc-pVTZ optimization with empirically corrected CBr, CCl, and CF bond lengths.  Calculated and experimental nqcc's are compared in Tables 1-4.  Structure parameters are given in Table 5.

 








 


 





In Tables 1 - 4, the subscripts a,b,c refer to the principal axes of the inertia tensor. Subscripts x,y,z refer to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the c-axis.  (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 (percentage of average of absolute experimental nqcc's).  RSD is the residual standard deviation of the calibration of the computional model for calculation of the nqcc's.

 








 








   








Table 1.  35Cl nqcc's in 79Br35ClCH2 (MHz).  Calculation was made on ro and ~re structures.
   










Calc / ro
Calc / ~re
Expt. [1]
   








Xaa - 35.69 - 36.06 - 33.64(70)

Xbb
- 4.89
- 4.42
- 5.79(41)

Xcc
40.58
40.48
39.43(81)

|Xab|
54.25
53.84
53.7(52)

 







RMS
1.45 (5.5 %)
1.72 (6.5 %)



RSD
0.49 (1.1 %)
0.49 (1.1 %)



 







Xxx
36.10
35.87
35.76

Xyy
40.58
40.48
39.43

Xzz - 76.68 - 76.35 - 75.19

ETA
0.058
0.060
0.04880

z,a
37.08
36.81
37.72

a,CCl
38.05
37.89



z,CCl
  0.97
  1.08



 








 








 








 
   








Table 2.  79Br nqcc's in 79Br35ClCH2 (MHz).  Calculation was made on ro and ~re structures.
   










Calc / ro
Calc / ~re
Expt. [1]
   








Xaa
383.01
385.58
383.33(59)

Xbb
- 75.15
- 79.02
- 75.80(37)

Xcc - 307.86 - 306.56 - 307.53(69)

|Xab|
373.28
368.74
372.4(13)

 







RMS
0.46 (0.18 %)
2.43 (0.91 %)



RSD
1.58 (0.39 %)
1.58 (0.39 %)



 







Xxx - 284.03 - 282.54 - 283.70

Xyy - 307.86 - 306.56 - 307.53

Xzz
591.90
589.09
591.23

ETA
0.0403
0.0401
0.04030

z,a
29.23
28.90
29.17

a,CBr
29.64
29.45



z,CBr
  0.41
  0.55



 








 







   








   








Table 3.  35Cl nqcc's in 81Br35ClCH2 (MHz).  Calculation was made on ro and ~re structures.
   










Calc / ro
Calc / ~re
Expt. [1]
   








Xaa - 35.62 - 35.99 - 34.82(48)

Xbb
- 4.79
- 4.49
- 5.39(28)

Xcc
40.58
40.48
40.21(55)

|Xab|
54.27
53.86
57.4(17)

 







RMS
0.56 (2.1 %)
0.86 (3.2 %)



RSD
0.49 (1.1 %)
0.49 (1.1 %)



 







Xxx
36.10
35.87
39.15

Xyy
40.58
40.48
40.21

Xzz - 76.68 - 76.35 - 79.36

ETA
0.058
0.060
0.01335

z,a
37.11
36.85
37.80

a,CCl
38.08
37.93



z,CCl
  0.97
  1.08



 








 








 








   








Table 4.  81Br nqcc's in 81Br35ClCH2 (MHz).  Calculation was made on ro and ~re structures.
   










Calc / ro
Calc / ~re
Expt. [1]
   








Xaa
320.43
322.57
317.73(69)

Xbb
- 63.22
- 66.45
- 62.13(39)

Xcc - 257.21 - 256.12 - 255.60(79)

|Xab|
311.59
307.80
311.6(8)

 







RMS
1.92 (0.91 %)
3.76 (1.77 %)



RSD
1.58 (0.39 %)
1.58 (0.39 %)



 







Xxx - 237.30 - 236.05 - 237.12

Xyy - 257.21 - 256.12 - 255.60

Xzz
494.51
492.17
492.72

ETA
0.0403
0.0408
0.03750

z,a
29.19
28.86
29.32

a,CBr
29.60
29.41



z,CBr
  0.41
  0.55



 








 








 


















Table 5.  BrClCH2 Structure parameters, ro [1] and ~re ( and degrees/minutes).
 














   ro   ~re














CBr 1.930 1.9274




CCl 1.768 1.7615




CH 1.074 1.0824




BrCCl 112o19' 112.66




ClCH 108o40' 108.55




HCH 110o56' 112.00










Z-Matrix
















Br








C 1 R2






Cl 2 R3 1 A3




H 2 R4 3 A4 1   D


H 2 R4 3 A4 1 - D


 








             ro    ~re















R2 = 1.930 1.9274





R3 = 1.768 1.7615





R4 = 1.074 1.0824





A3 = 112.3167 112.66





A4 = 108.6667 108.55





D = 119.5952 119.0196







 








 









[1] Y.Niide and I.Ohkoshi, J.Mol.Spectrosc. 136,17(1989).

 








 








BrClCF2 CH3Cl CH3Br CF2Cl2

CHF2Cl CF3Cl CF3Br CH2Cl2

CH2FCl CH2Br2





 








 








Table of Contents




Molecules/Chlorine




Molecules/Bromine




 








 













CBrClH2.html






Last Modified 21 July 2009