ClCH2CH2CH2CH3


 




 


Chlorine


Nuclear Quadrupole Coupling Constants

in 1-Chloro-n-Butane TT

 







 
 
Calculation of the chlorine nqcc's in 1-chloro-n-butane TT was made on approximate equilibrium structures given by MP2 optimization in conjunction with Pople-type bases, with empirical correction for the CH, C-C, and CCl bond lengths (~ re).  These given in Tables 1 and 2.  Structure parameters are given in Table 3, rotational constants in Table 4.
 
In Tables 1 - 2, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  Øz,CCl (degrees) is the angle between the principal z-axis of the nqcc tensor and the CCl bond axis.  ETA = (Xxx - Xyy)/Xzz.
RSD is the calibration residual standard deviation of the B1LYP/TZV(3df,2p) model for calculation of the chlorine nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's.
 
 
 
   




Table 1.  35Cl nqcc's in 1-chloro-n-butane TT (MHz).  Calculation was made on the ~ re structure, with interatomic angles given by (1) MP2/6-311+G(d,p) and (2) MP2/6-311+G(2d,p) optimizations.
   




Calc/~ re(1) Calc/~ re(2) Expt.
   



Xaa - 42.93 - 43.80
Xbb   6.98   7.89
Xcc 35.95 35.90
|Xab| 47.20 46.47
 
RSD 0.49 (1.1 %) 0.49 (1.1 %)
 
Xxx 35.41 35.22
Xyy 35.95 35.90
Xzz - 71.36 - 71.13
ETA 0.007 0.009
Øz,a 31.06 30.46
Øa,CCl 30.15 29.72
Øz,CCl   0.92   0.74
 

 
 
   




Table 2.  37Cl nqcc's in 1-chloro-n-butane TT (MHz).  Calculation was made on the ~ re structure, with interatomic angles given by (1) MP2/6-311+G(d,p) and (2) MP2/6-311+G(2d,p) optimizations.
   




Calc/~ re(1) Calc/~ re(2) Expt.
   



Xaa - 34.01 - 34.69
Xbb   5.68   6.40
Xcc 28.33 28.30
|Xab| 37.10 36.53
 
RSD 0.44 (1.1 %) 0.44 (1.1 %)
 
 
 
Table 3. 1-Chloro-n-Butane TT (Cs).  Heavy atom structure parameters, ~ re(1) and ~ re(2) (Å and degrees).   Complete structures are given here in Z-matrix format.
~ re(1) is ~ re bond lengths with MP2/6-311+G(d,p) interatomic angles,  ~ re(2) is ~ re bond lengths with MP2/6-311+G(2d,p) angles.
 

~ re(1) ~ re(2)
ClC(1) 1.7863 1.7863
C(1)C(2) 1.5111 1.5111
C(2)C(5) 1.5214 1.5214
C(5)C(8) 1.5209 1.5209
ClC(1)C(2) 111.35 111.67
C(1)C(2)C(5) 111.72 111.17
C(2)C(5)C(8) 112.09 111.98
 
Click on image to enlarge.

 
 
Table 4.  Rotational Constants (MHz).  35Cl Species.
~ re(1) ~ re(2)  Expt. [1]
A 16 992.3 17 114.9 16 867(5)
B   1 334.2   1 333.0   1 321.148(4)
C   1 276.2   1 275.7   1 263.943(4)
 

 
Substitution coordinates of the Cl atom were determined [1]:  These are (| a |, | b |, | c |) = (2.1418, 0.2044, 0 Å).  On the ~ re(1) structure, (| a |, | b |, | c |) = (2.1328, 0.2073, 0 Å); and on the ~ re(2) structure, = (2.1349, 0.2034, 0 Å).
 
 

[1]  S.Melandri, P.G.Favero, D.Damiani, W.Caminati, and L.B.Favero, J.Chem.Soc. Faraday Trans. 90,2183(1994).
 
 
1-Chloro-n-Butane GT 1-Chloro-n-Butane TG
1-Chloro-n-Butane GG 1-Chloro-n-Butane GG'
 

 








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Last Modified 14 Jan 2008