CF2BrCN





 




 
 


Bromine and Nitrogen


Nuclear Quadrupole Coupling Constants

in Bromodifluoroacetonitrile


 







 
 
Calculation was made here of the Br and N nqcc tensors in CF2BrCN on approximate equilibrium  (~re) molecular structures given by (1) MP2/aug-cc-pVTZ optimization with empirically corrected C-C, CN, CF, and CBr bond lengths, and (2) MP2/6-311+G(3df,3pd) optimization also with empirically corrected C-C, CN, CF, and CBr bond lengths.   Calculated nqcc tensors are given in Tables 1 - 4.  Structure parameters are given in Table 5, rotational constants in Table 6.
 
In Tables 1 - 4, 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 model for calculation of the nqcc's.
 
 
 
   







Table 1.  79Br nqcc's in CF2BrCN (MHz).  Calculation was made on (1) MP2/aug-cc-pVTZ and (2) MP2/6-311+G(3df,3pd) ~re molecular structures.
   








Calc (1)
Calc (2)
Expt [1]
   





Xaa 519.87 522.17 512.643(6)
Xbb - 209.31 - 210.32 - 204.693(6)
Xcc - 310.56 - 311.86 - 307.915(5)
|Xab| 292.72 292.98 297.0(1)
 
RMS 5.18 (1.52 %) 6.78 (1.98 %)
RSD 1.58 (0.39 %) 1.58 (0.39 %)
 
Xxx - 312.28 - 313.09 - 311.70(6)
Xyy - 310.56 - 311.86 - 307.915(5)
Xzz 622.84 624.94 619.65(6)
ETA - 0.0028 - 0.0020 - 0.0061(1)
Øz,a 19.38 19.33 19.814(5)
Øa,CBr 20.99 20.96
Øz,CBr   1.61   1.62
 

 
 
   







Table 2.  14N nqcc's in CF279BrCN (MHz).  Calculation was made on (1) MP2/aug-cc-pVTZ and (2) MP2/6-311+G(3df,3pd) ~re molecular structures.
   








Calc (1)
Calc (2)
Expt [1]
   





Xaa - 0.787 - 0.781 - 0.747(4)
Xbb - 1.682 - 1.684 - 1.673(6)
Xcc 2.469 2.465 2.420(4)
|Xab| 3.329 3.335 3.4(1)
 
RMS 0.037 (2.3 %) 0.033 (2.0 %)
RSD 0.030 (1.3 %) 0.030 (1.3 %)
 
Xxx 2.124 2.133 2.22(10)
Xyy 2.469 2.465 2.420(4)
Xzz - 4.594 - 4.597 - 4.64(10)
ETA 0.075 0.072 0.042(21)
Øz,a 48.83 48.85 48.9(1)
Øa,CN 49.15 49.28
Øz,CN   0.33   0.43
 
 
 
   







Table 3.  81Br nqcc's in CF2BrCN (MHz).  Calculation was made on (1) MP2/aug-cc-pVTZ and (2) MP2/6-311+G(3df,3pd) ~re molecular structures.
   








Calc (1)
Calc (2)
Expt [1]
   





Xaa 436.30 438.22 430.265(4)
Xbb - 176.84 - 177.67 - 173.037(6)
Xcc - 259.46 - 260.55 - 257.228(4)
|Xab| 242.09 242.31 245.5(1)
 
RMS 4.32 (1.50 %) 5.65 (1.97 %)
RSD 1.38 (0.40 %) 1.38 (0.40 %)
 
Xxx - 260.90 - 261.58 - 260.31(6)
Xyy - 259.46 - 260.55 - 257.228(4)
Xzz 520.36 522.12 517.54(6)
ETA - 0.0028 - 0.0020 - 0.0060(1)
Øz,a 19.15 19.10 19.570(6)
Øa,CBr 20.76 20.72
Øz,CBr   1.61   1.62
 
 
 
   







Table 4.  14N nqcc's in CF281BrCN (MHz).  Calculation was made on (1) MP2/aug-cc-pVTZ and (2) MP2/6-311+G(3df,3pd) ~re molecular structures.
   








Calc (1)
Calc (2)
Expt [1]
   





Xaa - 0.760 - 0.754 - 0.723(3)
Xbb - 1.709 - 1.710 - 1.703(5)
Xcc 2.469 2.465 2.426(4)
|Xab| 3.325 3.331 3.1(1)
 
RMS 0.033 (2.0 %) 0.029 (1.8 %)
RSD 0.030 (1.3 %) 0.030 (1.3 %)
 
Xxx 2.124 2.132 1.93(10)
Xyy 2.469 2.465 2.426(4)
Xzz - 4.594 - 4.597 - 4.35(10)
ETA 0.075 0.072 0.115(23)
Øz,a 49.06 49.08 49.5(1)
Øa,CN 49.38 49.51
Øz,CN   0.33   0.43
 
 
 
 
Table 5.  Bromodifluoroacetonitrile.  Structure parameters (Å and degrees).   (1) MP2/aug-cc-pVTZ optimized structure with ~re C-C, CN, CF, and CBr bond lengths, and (2) MP2/6-311+G(3df,3pd) optimized structure with ~re C-C, CN, CF, and CBr bond lengths.  Complete ropt and ~re structures are given here in Z-matrix format.
 
~re(1) ~re(2)

CC 1.4692 1.4710
CN 1.1564 1.1560
CBr 1.9243 1.9291
CF 1.3348 1.3354
BrCC 109.99 110.07
CCN 179.86 179.69
BrCF 109.58 109.50
FCF 107.93 108.14

 
 
Table 6.  CF279BrCN.  Rotational constants (MHz).  (1) MP2/aug-cc-pVTZ optimized structure with ~re C-C, CN, CF, and CBr bond lengths, and (2) MP2/6-311+G(3df,3pd) optimized structure with ~re C-C, CN, CF, and CBr bond lengths.
 
 ~re(1)   ~re(2)    Expt [1]
A 3480.53 3477.18 3464.121(1)
B 1745.44 1738.90 1742.5317(3)
C 1459.76 1455.93 1456.3421(3)
 
 
[1] G.S.Grubbs II, W.C.Bailey, and S.A.Cooke, J.Mol.Struct. 987,255(2011).
 
 
CHFClCN CHFBrCN CH2ClCN CH2BrCN
CHF2CN CH2FCN CH2BrCl CHF2Br
 

 








Table of Contents




Molecules/Nitrogen



Molecules/Bromine
 

 













CF2BrCN.html






Last Modified 27 Dec 2010