o-CH3-C6H4-Cl



 

 








Chlorine

Nuclear Quadrupole Coupling Constants


in ortho-Chlorotoluene


 







 

 

 




Diagonal chlorine nqcc's in o-chlorotoluene were first determined in 1990 by Nair and Epple [1].  The complete chlorine nqcc tensors were more recently determined by Gerhard et al. [2].
 
The nqcc's were calculated here on the molecular structure determined by Gerhard et al. [2] by MP2/6-311+G(2df,2p) optimization, and on a structure determined here by B3P86/6-31G(3d,3p) optimization.  These calculated nqcc's are compared with the experimental values in Tables 1 and 2.  Structure parameters (in Z-matrix format) are compared in Table 3.
 
In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia tensor, subscripts x,y,z to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertial c-axis, these are perpendicular to the plane of the molecule.  Ø (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 for the B1LYP/TZV(3df,2p) model for calculation of the nqcc's.
 

 







   






Table 1.  Chlorine nqcc's in o-Chlorotoluene (MHz).  Calculation was made on the MP2/6-311+G(2df,2p) ropt structure [2].
   









Calc.
Expt. [2]
   





35Cl Xaa - 68.42 - 67.97044(173)
Xbb 37.19 36.41199(188)
Xcc 31.23 31.55845(169)
|Xab| 15.02 14.52(53)
 
RMS 0.55 (1.2 %)
RSD 0.49 (1.1 %)
 
  Xxx 39.29 38.394(144)
Xyy 31.23 31.55845(169)
Xzz - 70.52 - 69.953(144)
ETA - 0.114 - 0.0977
Øz,a 7.94 7.77(27)
Øa,CCl 7.27 7.27
Øz,CCl 0.67 0.50
 
37Cl Xaa - 54.23 - 53.88672(216)
Xbb 29.62 29.01249(241)
Xcc 24.61 24.87423(222)
|Xab| 10.69 9.36(70)
 
RMS 0.43 (1.2 %)
RSD 0.44 (1.1 %)
 
 
 
   






Table 2.  Chlorine nqcc's in o-Chlorotoluene (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.
   









Calc.
Expt. [2]
   





35Cl Xaa - 68.50 - 67.97044(173)
Xbb 37.14 36.41199(188)
Xcc 31.36 31.55845(169)
|Xab| 15.18 14.52(53)
 
RMS 0.54 (1.2 %)
RSD 0.49 (1.1 %)
 
  Xxx 39.28 38.394(144)
Xyy 31.36 31.55845(169)
Xzz - 70.64 - 69.953(144)
ETA - 0.112 - 0.0977
Øz,a 8.02 7.77(27)
Øa,CCl 7.26 7.26 *
Øz,CCl 0.76 0.51 *
 
37Cl Xaa - 54.30 - 53.88672(216)
Xbb 29.59 29.01249(241)
Xcc 24.72 24.87423(222)
|Xab| 10.82 9.36(70)
 
RMS 0.42 (1.2 %)
RSD 0.44 (1.1 %)
 
 
* Calculated here on B3P86/6-31G(3d,3p) structure.
 
 
  
Table 3.  o-Chlorotoluene.  Molecular structure parameters, ropt (Å and degrees).
 
C
C 1 R1
C 2 R2 1 A2
C 3 R3 2 A3 1 0.
C 4 R4 3 A4 1 0.
C 5 R5 4 A5 1 0.
C 2 R6 3 A6 1 180.
Cl 1 R7 6 A7 2 180.
H 3 R8 2 A8 1 180.
H 4 R9 3 A9 1 180.
H 5 R10 4 A10 1 180.
H 6 R11 5 A11 1 180.
H 7 R12 2 A12 1 180.
H 7 R14 2 A14 1   D
H 7 R14 2 A14 1 - D
 
MP2/ B3P86/
6-311+G(2df,2p) 6-31G(3d,3p)
R1 1.3981 1.3982
R2 1.3971 1.3958
R3 1.3918 1.3889
R4 1.3919 1.3890
R5 1.3912 1.3886
R6 1.4974 1.4981
R7 1.7373 1.7398
R8 1.0827 1.0858
R9 1.0810 1.0846
R10 1.0811 1.0846
R11 1.0806 1.0835
R12 1.0871 1.0912
R14 1.0892 1.0938
A2 116.97 116.81
A3 121.83 121.87
A4 119.75 119.85
A5 119.85 119.78
A6 121.40 121.25
A7 118.48 118.31
A8 118.43 118.42
A9 119.95 119.89
A10 120.52 120.55
A11 121.10 121.12
A12 110.49 110.65
A14 111.05 111.28
D   59.42   59.40
 
 
[1] K.P.R.Nair and K.Epple, Chem.Phys.Lett. 166,146(1990).
[2] D.Gerhard, A.Hellweg, I.Merke, W.Stahl, M.Baudelet, D.Petitprez, and G.Wlodarczak, J.Mol.Spectrosc. 220,234(2003).
 
 

p-Chlorotoluene Chlorobenzene

1,3-Chlorofluorobenzene 1,3-Dichlorobenzene
1,4-Chlorofluorobenzene 1,4-Dichlorobenzene
1,2-Chlorofluorobenzene 1,2-Dichlorobenzene
cis-2-Chlorophenol trans-2-Chlorophenol
 
 

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Last Modified 9 Aug 2003