ClH2C-CH2Cl



 



















 





 









Chlorine


Nuclear Quadrupole Coupling Constants

in gauche-1,2-Dichloroethane


 








 








 








Chlorine nqcc's in gauche-1,2-dichloroethane were first determined by Sugie et al. [1], and revisited by  Dikkumbura et al. [2].  Calculation was made here of the nqcc's on structures given by  MP2/aug-cc-pVTZ optimization (ropt) and on this same structure but with empirically corrected CCl and C-C bond lengths (reemp).  Calculated and experimental [2] nqcc's are compared in Tables 1 - 3.  Structure parameters are given in Table 4, rotational constants in Table 5.

 








In Tables 1 - 3, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  z,CCl (degrees) is the angle between the principal z-axis of the nqcc tensor and the CCl bond axis.  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 chlorine efg's/nqcc's.

 









 








NOTE:  The experimental results given below in Tables 1 - 3 were derived here using Kisiel's program QDIAG.f and data given in Ref. [2].


 








 
   








Table 1.  Cl nqcc's in gauche-35ClH2C-CH235Cl  (MHz).  Calculation was made on ropt and reemp structures.

   










Calc /ropt
Calc /reemp
 Expt. [2]
   








Xaa
- 0.52
- 0.51
- 1.1523(14)

Xbb - 28.19 - 28.13 - 27.5129(14)

Xcc
28.71
28.64
28.6651(14)

Xab* 50.04 49.93
49.89(4) **


Xac* - 16.43 - 16.41
16.51(6) **


Xbc* 22.98 22.96
22.70(9) **


 







RMS
0.53 (2.8 %) 0.51 (2.7 %)


RSD
0.49 (1.1 %) 0.49 (1.1 %)


 







Xxx
36.03
35.96
35.95(6)


Xyy
38.00
37.93
37.68(7)


Xzz - 74.03 - 73.89 -
73.63(6)


ETA
0.0266
0.0266
0.0236(12)


z,CCl







 








 








* The algebraic signs of the off-diagonal nqcc's depend on the orientation of the molecule with respect to positive/negative sense of the a,b,c axes.  Here,  Xac is negative, while for one Cl, Xab and Xbc are both positive, and for the other, both negative. The product XabXacXbc is negative, independent of positive/negative sense of a,b,c axes.

** Absolute value.


 









 








   








Table 2.  Cl nqcc's in gauche-35ClH2C-CH237Cl  (MHz).  Calculation was made on ropt and reemp structures.  See Table 1 footnotes.

   










Calc /ropt
Calc /reemp
 Expt. [2]

   








Xaa (35Cl)
+0.22
+0.23
- 0.417(5)

Xbb - 28.90 - 28.83 - 28.217(4)

Xcc
28.68
28.60
28.634(4)

Xab 49.82 49.71
49.9(3)


Xac - 16.29 - 16.27
15.9(16)


Xbc 23.14 23.12
22.8(5)


 







RMS
0.54 (2.8 %) 0.52 (2.7 %)


RSD
0.49 (1.1 %) 0.49 (1.1 %)


 







Xaa (37Cl)
- 1.05

- 1.04

- 1.536(4)


Xbb -
21.66 -
21.61 -
21.130(5)


Xcc
22.71
22.65
22.667(5)


Xab 39.64 39.56
39.15(30)


Xab -
13.00
-
12.99

13.4(14)


Xab 17.91
17.89

18.0(5)











RMS

0.41 (2.7 %)

0.40 (2.6 %)




RSD

0.44 (1.1 %)
0.44 (1.1 %)



 









 








 









   








Table 3.  Cl nqcc's in gauche-37ClH2C-CH237Cl  (MHz).  Calculation was made on ropt and reemp structures.  See Table 1 footnotes.

   










Calc /ropt
Calc /reemp
 Expt. [2]
   








Xaa
- 0.46
- 0.45
- 0.955(3)

Xbb - 22.22 - 22.17 - 21.687(3)

Xcc
22.68
22.62
22.642(3)

Xab 39.47 39.39
39.319(19)


Xac - 12.90 - 12.89
12.92(26)


Xbc 18.03 18.02
17.81(14)


 







RMS
0.41 (2.7 %) 0.40 (2.7 %)


RSD
0.49 (1.1 %) 0.49 (1.1 %)


 






















Table 4.  gauche-1,2-Dichloroethane.  MP2/aug-cc-pVTZ Structure Parameters ( and degrees).  Corrected bond lengths (reemp) are given in parentheses.
 


Point group: C2






 Cl
 C,1,B1
 C,2,B2,1,A1
 Cl,3,B3,2,A2,1,D1,0
 H,2,B4,1,A3,3,D2,0
 H,2,B5,1,A4,3,D3,0
 H,3,B6,2,A5,1,D4,0
 H,3,B7,2,A6,1,D5,0




 B1=1.78080451     (1.7775)
 B2=1.50794312     (1.5065)
 B3=1.78080451     (1.7775)
 B4=1.08641546
 B5=1.08833052
 B6=1.08641546
 B7=1.08833052
 A1=111.68651807
 A2=111.68651807
 A3=107.45295086
 A4=107.04664925
 A5=111.14618921
 A6=109.57992105
 D1=-67.68678709
 D2=-122.14005181
 D3=119.94422713
 D4=52.30596173
 D5=173.86975497








 








 



Table 5.  gauche-35ClH2C-CH235Cl.  Rotational Constants (MHz).
   



   ropt   reemp    Expt [2]






A 9912.
9943.
9933.6248(11)

B 2295.
2302.
2266.92137(30)

C 1984.
1990.
1962.76862(21)
 


 









 









[1] M.Sugie, M.Kato, C.Matsumura, and H.Takeo, J.Mol.Struct. 413-414,487(1997).

[2] A.S.Dikkumbura, E.R.Webster, R.E.Dorris, R.A.Peebles, S.A.Peebles, N.A.Seifert, and B.H.Pate, Abstract MI13, 71st International Symposium on Molecular Spectroscopy, Champaign-Urbana, Ill. 2016.

 









 








ClH2C-CH3 ClH2C-CHF2 ClF2C-CH3 ClF2C-CHF2

ClH2C-CH2F ClH2C-CF3 ClF2C-CH2F ClF2C-CF3

Cl2HC-CH3 Cl3C-CH3 Cl3C-CF3


ClFHC-CH3 ClFHC-CF3



 








 








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Molecules/Chlorine




 








 













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Last Modified 28 July 2016