CH3SiHCl2



 









Chlorine


Nuclear Quadrupole Coupling Constants


in Methyldichlorosilane


 







 
 
The diagonal components of the 35Cl nqcc tensor in methyldichlorosilane were determined, and a partial ro structure was derived, by Endo et al. [1].
 
Calculation was made here of the 35Cl nqcc tensor on the partial ro structure.  Calculated and experimental nqcc's are compared in Table 1.  Structure parameters are given in Table 2.
 
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.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
RMS is the root mean square difference between calculated and experimental nqcc's (percent 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 chlorine nqcc's. 

 







 
 
   







Table 1. Chlorine nqcc's in CH3SiHCl2 (MHz).  Calculation was made on the partial ro molecular structure of Endo et al. [1].
   










Calc.
Expt. [1]
   






35Cl Xaa - 20.04 - 19.1(3)
Xbb   5.38   5.4(13)
Xcc 14.66 13.7(14)
Xab * 22.70
Xac * - 13.15
Xbc *   8.72
 
RMS 0.8 (6.1 %)
RSD 0.49 (1.1 %)
 
Xxx 18.13
Xyy 19.93
Xzz - 38.06
ETA 0.047
Øz,SiCl 1.4
 

 
* The algebraic signs of the off-diagonal components depend on the orientation of the molecule with respect to a,b,c axes.  Here, the algebraic signs correspond to the atomic a,b,c coordinates given in Table 3.
 
 
Table 2.  Methyldichlorosilane.  Structure Parameters, partial ro [1] (Å and degrees).
 
SiC 1.850 (ass)
SiCl 2.040
SiH 1.467 (ass)

CH 1.093 (ass)
CSiCl 109.8
SiCH 109.5 (ass)
CSiH 110.9 (ass)
ClSiCl 108.8
Z-Matrix
C
Si 1 R1
H 2 R2 1 A1
Cl 2 R3 1 A2 3 - D1
Cl 2 R3 1 A2 3 D1
H 1 R4 2 A3 3 - D2
H 1 R4 2 A3 3 D2
H 1 R4 2 A3 3 D3
 
R1 = 1.850 A2 = 109.8
R2 = 1.467 A3 = 109.5
R3 = 2.040 D1 = 120.2
R4 = 1.093 D2 = 60.
A1 = 110.9 D3 = -180.
 
 
Table 3.  Methyldichlorosilane.  Atomic Coordinates.  The nqcc tensor in Table 1 is for the Cl atom at a = +1.6589Å.
 a (Å)  b (Å)  c (Å)
C 0 2.0780 0.3466
Si 0 0.4077 - 0.4488
H 0 0.5244 - 1.9111
Cl ± 1.6589 - 0.6313 0.1258
H ± 0.8923 2.6289 0.0383
H 0 1.9644 1.4337
 
 
[1] K.Endo, H.Takeo, and C.Matsumura, Bull.Chem.Soc. Japan 50,626(1977).

 








 








CH3SiH2Cl CH3SiCl3 CH3SiCl2CH3
SiH3Cl SiH2Cl2 SiHCl3
 

 








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Last Modified 4 Aug 2006