CH2Cl-C(=O)OH




































 









Chlorine


Nuclear Quadrupole Coupling Constants


in Chloroacetic Acid


 








 








Calculation of the chlorine nqcc tensors was made here on structures given by MP2/aug-cc-pVTZ(G03) optimization (ropt), and on this optimized structure but with corrected CCl, C-C, and C=O bond lengths (~ re, see here).  These nqcc's are compared with the experimental values [1] in Table 1.  Structure parameters are given in Table 2, rotational constants in Table 3.

 








In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the molecular symmetry plane.  (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, which may be taken as an estimate ofthe uncertainty in the calculated nqcc's.

 








  








   








Table 1.  Chlorine nqcc's in CH2Cl-C(=O)OH (MHz).  Calculation was made on the (1) ropt and (2) ~ re structures.

 









Calc (1)
Calc (2)
Expt. [1]
   








Xaa(35Cl) - 50.65 - 50.55 - 47.5(12)

Xbb
11.55
11.57
10.4(7)

Xcc
39.10
38.98
37.1(12)

|Xab|
50.00
49.78



 







RMS
2.2 (7.1 %)
2.2 (6.9 %)



RSD
0.49 (1.1 %)
0.49 (1.1 %)



 







Xxx
39.30
39.18



Xyy
39.10
38.98



Xzz - 78.39 - 78.16



ETA - 0.0026 - 0.0025



z,a
29.04
29.02



a,CCl
29.51
29.48



z,CCl
  0.47
  0.46



 







Xaa(37Cl) - 39.97 - 39.89



Xbb
  9.16
  9.17



Xcc
30.81
30.72



|Xab|
39.34
39.20



 







RSD
0.44 (1.1 %)
0.44 (1.1 %)



 







   








 












Table 2.  Chloroacetic Acid.  Molecular structure parameters, ropt and ~ re ( and degrees).
 


Point Group Cs
  ropt  ~ re





ClC   1.7620   1.7587
CH   1.0871   1.0871
C-C   1.5114   1.5098
C=O   1.2034   1.1960
CO   1.3556   1.3556
OH   0.9702   0.9702
ClCC   112.24   112.24
CCH   108.95   108.95
HCC=O 120.89 120.89
CC=O   106.18   106.18

OC=O   124.14   124.14

COH   106.18   106.18


 








 













Table 3.  Chloroacetic Acid.  Rotational constants (MHz).  35Cl species.
 



 
   ropt    ~ re    Expt [1]






A 10 473.4 10 546.4 10514.872(17)

B   2 361.7   2 367.3   2351.358(4)

C   1 950.5   1 956.8   1946.028(4)


 








 








[1] B.P. van Eijck, A.A.J.Maagdenberg, and J.Wanrooy, J.Mol.Struct. 22,61(1974).

 








 








CH2Cl-C(=O)F CH2Cl-CH3 CH2Br-C(=O)OH


 








 








Table of Contents




Molecules/Chlorine




 








 













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Last Modified 20 April 2008