




















3ClC_{4}H_{3}S































Chlorine and Sulfur



Nuclear
Quadrupole Coupling Constants 



in 3Chlorothiophene 

































Calculation of the
chlorine
nqcc's in 3chlorothiophene was
made on molecular structures obtained by B3PW91/631G(2d,2pd) and
B3P86/631G(3d,3p) optimization. Comparison of the calculated and
experimental nqcc's [1] in Tables 1 and 2 suggests an error in the
assignment of experimental coupling constants with respect to intertial
axes. This conclusion is strongly supported by an investigation
of the microwave spectrum of the title molecule by Caminati et al. [2],
wherein X_{aa} and X_{bb} respectively are reported as 73.2(5) and 38.2(3) MHz.













Calculated ^{33}S nqcc's are given in Table 3. Structure
parameters are given in Table 4, atomic coordinates in Table 5, and
rotational constants in Table 6. 












In Tables 1  3, 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 yaxis is chosen coincident with the inertia caxis, these
are perpendicular to the plane of the molecule. Ø (degrees)
is the angle between its subscripted parameters. ETA = (X_{xx}
 X_{yy})/X_{zz}. 


RMS is the root mean square
difference between calculated and experimental nqcc's (percent of
average absolute experimental nqcc). RSD is the residual standard deviation
of calibration of the model for calculation of
the nqcc's. 
































Table
1. ^{35}Cl nqcc's in 3Chlorothiophene^{32}S
(MHz). RMS* is the root mean square difference between calculated and
experimental nqcc's assuming the experimental X_{bb} and X_{cc}
to be reversed (see Caminati et al. [2]).












Calculation was made on 



the [a] B3PW91/631G(2d,2pd) r_{opt} structure, and 



the [b] B3P86/631G(3d,3p) r_{opt} structure. 













Calc. [a]


Calc. [b] 

Expt. [1] 











X_{aa} 
 
73.26 
 
72.78 
 
72.62(16) 


X_{bb} 

38.24 

38.08 

34.59(90) 


X_{cc} 

35.02 

34.70 

38.03(91) 


X_{ab} 

9.58 

9.63 













RMS 

2.76 (5.7 %) 
2.79 (5.8 %) 



RMS* 

0.46 (0.96 %) 
0.12 (0.25 %) 



RSD 

0.49 (1.1 %) 
0.49 (1.1 %) 












X_{xx} 

39.06 

38.92 




X_{yy} 

35.02 

34.70 




X_{zz} 
 
74.08 
 
73.62 




ETA 
 
0.054 
 
0.057 




Ø_{z,a} 

4.87 

4.93 




Ø_{a,CCl} 

5.16 

5.22 




Ø_{z,CCl} 

0.28 

0.30 



































Because B3PW91/631G(2d,2pd)
optimization gives structures on which good agreement is obtained
between calculated and experimental ^{33}S
nqcc's in thiophene and thiazole, and because B3P86/631G(3d,3p)
works for chlorine substituted benzenes and pyridines, as well as
2chlorothiophene, calculation was made on a structure consisting of
the B3PW91/631G(2d,2pd) ring with the B3P86/631G(3d,3p) CCl bond
length. The results are given below in Table 2 for both ^{35}Cl and ^{37}Cl, and in Table 3 for ^{33}S.
































Table 2. Chlorine nqcc's in 3Chlorothiophene^{32}S
(MHz). Calculation was made on the B3PW91/631G(2d,2pd) ring
structure with the B3P86/631G(3d,3p) optimized CCl bond length.
RMS* is the root mean square difference between calculated and
experimental nqcc's assuming the experimental X_{bb} and X_{cc}
to be reversed (see Caminati et al. [2]). 













Calc. 

Expt. [1] 










^{35}Cl 
X_{aa} 
 
72.74 
 
72.62(16) 



X_{bb} 

38.07 

34.59(90) 



X_{cc} 

34.67 

38.03(91) 



X_{ab} 

9.56 













RMS 

2.79 (5.8 %) 




RMS* 

0.05 (0.11 %) 




RSD 

0.49 (1.1 %) 












X_{xx} 

38.89 





X_{yy} 

34.67 





X_{zz} 
 
73.56 





ETA 
 
0.057 





Ø_{z,a} 

4.90 





Ø_{a,CCl} 

5.18 





Ø_{z,CCl} 

0.28 












^{37}Cl 
X_{aa} 
 
57.36 
 
57.57(16) 



X_{bb} 

30.03 

27.46(75) 



X_{cc} 

27.32 

30.11(76) 



X_{ab} 

7.37 













RMS 

2.79 (5.7 %) 





RMS* 

0.15 (0.40 %) 





RSD 

0.44 (1.1 %) 












































Table 3.
^{33}S nqcc's in 3Chlorothiophene^{35}Cl
(MHz). Calculation was
made on the B3PW91/631G(2d,2pd) ring structure with the B3P86/631G(3d,3p) optimized CCl bond length. 












Calc. [a] B3LYP/6311G(3df,3p) Model. 



Calc. [b] B3LYP/TZV+(3df,3p)
Model. 













Calc. [a]


Calc. [b] 

Expt. 











X_{aa} 

 1.93 

 1.90 




X_{bb} 
 
20.30 
 
20.37 




X_{cc} 

22.23 

22.27 




X_{ab} 

14.67 

14.73 













RSD 

0.39 (1.7 %) 
0.35 (1.5 %) 












X_{xx} 

6.20 

6.25 




X_{yy} 

22.23 

22.27 




X_{zz} 
 
28.42 

28.52 




ETA 

0.564 

0.561 




Ø_{x,a} 

28.98 

28.96 




Ø_{a,bi} 

27.79 

27.79 




Ø_{x,bi}* 

1.19 

1.17 

























* Angle between the xaxis and the bisector ( 'bi'
) of the CSC angle. 

















Table 4. 3Chlorothiophene and Thiophene. Structure parameters
(Å and degrees). 







B3P86 
B3PW91 
B3PW91 


X = Cl 
X = Cl 
X = H 






S(1)C(2) 
1.7090 
1.7181 
1.7197 

C(2)C(3) 
1.3663 
1.3648 
1.3660 

C(3)C(4) 
1.4203 
1.4222 
1.4229 

C(4)C(5) 
1.3646 
1.3637 
1.3660 

C(5)S(1) 
1.7116 
1.7199 
1.7197 

C(2)H(2) 
1.0786 
1.0773 
1.0787 

C(3)X(3) 
1.7240 
1.7331 
1.0816 

C(4)H(4) 
1.0815 
1.0800 
1.0816 

C(5)H(5) 
1.0799 
1.0786 
1.0787 

C(5)S(1)C(2) 
92.40 
92.25 
91.95 

S(1)C(2)C(3) 
110.54 
110.37 
111.42 

C(2)C(3)C(4) 
113.77 
114.05 
112.60 

C(3)C(4)C(5) 
111.40 
111.50 
112.60 

C(4)C(5)S(1) 
111.90 
111.83 
111.42 

S(1)C(2)H(2) 
121.39 
121.20 
119.93 

S(1)C(5)H(5) 
119.98 
119.85 
119.93 

C(3)C(4)H(4) 
123.88 
123.69 
124.04 

C(4)C(3)X(3) 
122.76 
122.62 
124.04 





























Table 5. 3Chlorothiophene, normal species. Atomic
coordinates. B3PW91/631G(2d,2pd) ring structure with the B3P86/631G(3d,3p) optimized CCl bond length. 









a (Å) 

b (Å) 







S(1) 
 
1.9310 
 
0.4933 

C(2) 
 
0.2982 
 
1.0281 

C(3) 

0.5516 

0.0399 

C(4) 
 
0.1038 

1.3021 

C(5) 
 
1.4602 

1.1609 

H(2) 
 
0.0546 
 
2.0774 

Cl(3) 

2.2685 
 
0.1157 

H(4) 

0.4177 

2.2478 

H(5) 
 
2.2130 

1.9334 




























Table 6. 3Chlorothiophene, normal species. Rotational Constants (MHz). 






[a] B3PW91/631G(2d,2pd)
opt structure. 

[b] B3P86/631G(3d,3p)
opt structure. 

[c] B3PW91/631G(2d,2pd)
ring structure with the B3P86/631G(3d,3p) optimized CCl bond length. 






Calc [a] 
Calc [b] 
Calc [c] 
Expt. [1] 





A 
7149.7 
7184.0 
7150.4 
7144.19(41) 
B 
1503.4 
1512.0 
1509.9 
1508.3654(31) 
C 
1242.2 
1249.1 
1246.6 
1245.0304(31) 























[1] Y.Niide and I.Ohkoshi, J.Mol.
Spectrosc. 130,46(1988). 


[2] W.Caminati, B.Velino,
F.Caccinelli, R.S.Cataliotti, S.M.Murgia, G.Paliani, and S.Santucci,
J.Mol.Struct. 174,285(1988): X _{aa} and X_{bb} respectively are reported as 73.2(5) and 38.2(3) MHz. 






















Thiophene 
Thiazole 
2Bromothiophene 

2Chlorothiophene 
3Bromothiophene 






















Table of Contents 





Molecules/Chlorine 





Molecules/Sulfur 






























3ClThioph.html 






Last
Modified 15 Feb 2015 









