CH3CH2SiH2Cl





 








 








Chlorine

Nuclear Quadrupole Coupling Constants


in Ethylchlorosilane


 


















Chlorine nqcc's in both gauche and trans conformers of ethylchlorosilane were determined by Typke et al. [1]. 












gauche

trans

































At the MP2/6-311+G(d,p) level of theory, Egauche <  Etrans by 1.3 kJ/mole.

 








Calculation of the chlorine nqcc tensors in gauche and trans conformers was made here on molecular ro structure (structure II in Table 5 of ref. [1]), and on a structure given by MP2/6-311+G(d,p) optimization.  Calculated and experimental nqcc's are compared in Tables 1and 2.  Structure parameters are given in Z-matrix format in Table 3, rotational constants in Table 4.

 








In Tables 1 and 2, 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.   ETA = (Xxx - Xyy)/Xzz.  Ø (degrees) is the angle between its subscripted parameters.  RMS is the root measn square difference between calculated and experimental diagonal nqcc's.  RSD is the residual standard deviation of calibration of the B1LYP/TZV(3df,2p)  model for calculation of the efg's/nqcc's.

 








 








   







Table 1.  Chlorine nqcc's in gauche Ethylchlorosilane (MHz).  Calculation was made on experimental ro and MP2/6-311+G(d,p) optimized molecular structures.
   









Calc /ro
Calc /MP2
  Expt. [1] *
 








Xaa (35Cl) -
 10.25
- 9.01
- 8.989(82)

Xbb
- 8.20
- 9.69
- 9.150(54)

Xcc
18.45
18.70
18.139(54)

Xab
27.67
28.32



Xac
  4.20
  4.55



Xbc
- 4.72
- 5.05



 







RMS
0.93 (7.7 %)
0.45 (3.7 %)



RSD
0.49 (1.1 %)
 0.49 (1.1 %)


 







Xxx
18.22
18.82



Xyy
19.41
19.65



Xzz -
 37.63
 -
 38.47



ETA
0.0315
0.0217



Øz,SiCl
0.55
0.73



 







Xaa (37Cl)
- 8.59
- 7.63
- 7.08(60)

Xbb
- 5.97
- 7.12
- 6.55(36)

Xcc
14.56
14.76
13.63(36)

Xab
21.80
22.33



Xac
  3.30
  3.58



Xbc
- 3.63
- 3.89












RMS
1.08 (11.9 %)
0.80 (8.8 %)



RSD
0.44 (1.1 %)
0.44 (1.1 %)













 








* Calculated here from experimental Xaa + Xbb = 8.989(82) and Xaa - Xbb = -27.289(71) MHz for 35Cl; and Xaa + Xbb = 7.08(60) and Xaa - Xbb = -20.17(39) MHz for 37Cl.

 








 








   







Table 2.  Chlorine nqcc's in trans Ethylchlorosilane (MHz).  Calculation was made on experimental ro and MP2/6-311+G(d,p) optimized molecular structures.
   









Calc /ro
Calc /MP2
Expt. [1] *
 








Xaa (35Cl) -
 28.04
 -
 27.69
 -
 26.94(39)

Xbb
  8.63
  8.00
  7.9(17)

Xcc
19.41
19.69
19.1(17)

|Xab|
21.37
22.69



 







RMS
0.80 (4.4 %)
0.56 (3.1 %)



RSD
0.49 (1.1 %)
 0.49 (1.1 %)


 







Xxx
18.45
19.02



Xyy
19.41
19.69



Xzz -
 37.86
 -
 38.71



ETA
0.0251
0.0173



Øz,a
24.68
25.91



Øa,SiCl
25.15
25.30



Øz,SiCl
  0.47
  0.60



 







Xaa (37Cl) -
 22.22
 -
 21.95
 -
 17.35(84)

Xbb
  6.93
  6.43
11.6(54)

Xcc
15.29
15.52
  5.8(54)

|Xab|
16.73
17.77












RMS
6.73 (58. %)
6.76 (58. %)



RSD
0.44 (1.1 %)
0.44 (1.1 %)













 








 * Calculated here from experimental Xaa + Xbb = 26.94(39) and Xaa - Xbb = -11.2(34) MHz for 35Cl; and Xaa + Xbb = 17.35(84) and Xaa - Xbb = 5.8(108) MHz for 37Cl.

 








 








 




Table 3. Ethylchlorosilane.  Experimental ro and MP2/6-311+G(d,p) optimized structure parameters (Å and degrees).
 





gauche Ethylchlorosilane








 C
 C,1,B1
 Si,2,B2,1,A1
 Cl,3,B3,2,A2,1,D1,0
 H,1,B4,2,A3,3,D2,0
 H,1,B5,2,A4,3,D3,0
 H,1,B6,2,A5,3,D4,0
 H,2,B7,1,A6,3,D5,0
 H,2,B8,1,A7,3,D6,0
 H,3,B9,2,A8,1,D7,0
 H,3,B10,2,A9,1,D8,0








      ro      MP2









B1=1.5318
B2=1.8694
B3=2.0601
B4=1.0823
B5=1.0823
B6=1.0823
B7=1.1071
B8=1.1071
B9=1.4780
B10=1.4780
A1=112.99
A2=109.89
A3=111.89
A4=111.89
A5=111.89
A6=112.08666953
A7=112.08666953
A8=113.82
A9=113.82
D1=59.63
D2=180.0
D3=60.0
D4=-60.0
D5=-117.95194779
D6=117.95194779
D7=-58.05
D8=177.31
  B1=1.53693569
 B2=1.86672263
 B3=2.06778962
 B4=1.09331176
 B5=1.09447426
 B6=1.09323248
 B7=1.09824099
 B8=1.09633512
 B9=1.47355417
 B10=1.47258133
 A1=113.90893516
 A2=109.17154389
 A3=111.08786329
 A4=111.1774821
 A5=111.11977662
 A6=110.02052054
 A7=110.26696279
 A8=110.90070391
 A9=111.78231871
 D1=60.23536391
 D2=178.61620057
 D3=58.65585532
 D4=-61.31150595
 D5=-120.51067997
 D6=122.57749789
 D7=-57.45779768
 D8=178.80814306

 




 




trans Ethylchlorosilane








 C
 C,1,B1
 Si,2,B2,1,A1
 Cl,3,B3,2,A2,1,D1,0
 H,1,B4,2,A3,3,D2,0
 H,1,B5,2,A4,3,D3,0
 H,1,B6,2,A5,3,D4,0
 H,2,B7,1,A6,3,D5,0
 H,2,B8,1,A7,3,D6,0
 H,3,B9,2,A8,1,D7,0
 H,3,B10,2,A9,1,D8,0








      ro      MP2








B1=1.5318
B2=1.8694
B3=2.0601
B4=1.0823
B5=1.0823
B6=1.0823
B7=1.1071
B8=1.1071
B9=1.4780
B10=1.4780
A1=111.30
A2=109.89
A3=111.89
A4=111.89
A5=111.89
A6=112.08666953
A7=112.08666953
A8=113.82
A9=113.82
D1=180.0
D2=180.0
D3=60.0
D4=-60.0
D5=121.83
D6=-121.83
D7=62.32
D8=-62.32
  B1=1.53870443
 B2=1.86693258
 B3=2.06616457
 B4=1.09328458
 B5=1.09439534
 B6=1.09439534
 B7=1.0959093
 B8=1.0959093
 B9=1.47319951
 B10=1.47319951
 A1=112.36148493
 A2=109.9516565
 A3=111.03306368
 A4=111.39550922
 A5=111.39550922
 A6=108.72466019
 A7=108.72466019
 A8=110.92623349
 A9=110.92623349
 D1=180.
 D2=180.
 D3=60.16666489
 D4=-60.16666489
 D5=122.22089491
 D6=-122.22089491
 D7=61.33378521
 D8=-61.33378521

 





 








 



Table 4.  Ethylchlorosilane, 35Cl species.  Rotational Constants (MHz).  Calc = ro [1] and MP2/6-311+G(d,p) optimized molecular structures.







    Calc /ro Calc /MP2     Expt. [1]





   gauche A
      7189.
     7133.
   7191.8752(59)

B
      2587.
     2577.
   2585.1897(33)

C
      2085.
     2075.
   2083.6754(33)





   trans A
    14740.
   14710.
 14742.5(21)

B
      1876.
     1861.
   1876.7444(37)

C
      1734.
     1720.
   1733.8894(33)



  








[1] V.Typke, M.Dakkouri, and W.Zeil, Z.Naturforsch. 29a,1081(1974).

 








 








SiH3Cl
(CH3)3SiCl
 CH3SiF2Cl

SiF3ClCH3SiH2Cl










 








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Molecules/Chlorine




 








 













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Last Modified 15 Jan 2016