ClC(=O)-O-CH3
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Chlorine

Nuclear Quadrupole Coupling Constants


in Methylchloroformate


 








 


















Calculation of the 14N nqcc's in methylchloroformate was made on the rs structure of Durig and Griffin [1] and on the re structure of Groner and Warren [2].  These are compared with experimental nqcc's in Tables 1 - 4.  Structure parameters are shown in Table 5.

 








In Tables 1 - 4, 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 y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the symmetry plane of the molecule.  Ø (degrees) is the angle between its subscripted parameters. ETA = (Xxx - Xyy)/Xzz.

RMS is the root mean square difference between clculated and experimental diagonal nqcc's (percent of average experimental nqcc).  RSD is the residual standard deviation of calibration of the B1LYP/TZV(3df,2p) model for calculation of the Cl efg's/nqcc's.

 








 








   








Table 1. Chlorine nqcc's in ClC(=O)OCH3 (MHz).  Calculation was made on the rs and re structures.
   











Calc /rs
Calc /re
Expt. [1]
   








35Cl Xaa - 58.43 -
 58.97
 - 59.8(5)


Xbb
31.28
32.02
31.2(10)


Xcc
27.16
26.95
28.6(10)


|Xab|
35.69
33.53



 









RMS
1.2 (2.9 %)
1.2 (2.9 %)




RSD
0.49 (1.1 %)
0.49 (1.1 %)



 








37Cl Xaa - 46.39 -
 46.79
 - 46.4(5)


Xbb
24.99
25.55
25.4(10)


Xcc
21.40
21.24
21.0(10)


|Xab|
27.69
26.00



 









RMS
0.3 (1.1 %)
0.3 (0.9 %)




RSD
0.44 (1.1 %)
0.44 (1.1 %)



 








   








 








   








Table 2. Chlorine nqcc's in ClC(=O)OCD3 (MHz).  Calculation was made on the rs and re structures.
   











Calc /rs
Calc /re
Expt. [1]
   








35Cl Xaa - 57.15 -
 57.82
 - 56.7(5)


Xbb
30.00
30.87
29.8(10)


Xcc
27.16
26.95
26.9(10)


|Xab|
37.24
35.05



 









RMS
0.3 (0.8 %)
0.9 (2.4 %)




RSD
0.49 (1.1 %)
0.49 (1.1 %)



 









Xxx
43.74


43.6 *


Xyy
27.16


26.9(10)


Xzz - 70.90

- 70.5


ETA - 0.234

- 0.237


Øz,a
20.26


20.36


Øa,CCl
21.0


21.0


Øz,CCl
  0.7


  0.6

 









 








* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal Xab = 37.24 MHz.

 








 








   








Table 3. Chlorine nqcc's in ClC(=O)O13CH3 (MHz).  Calculation was made on the rs and re structures.
   











Calc /rs
Calc /re
Expt. [1]
   








35Cl Xaa - 57.99 -
 58.56
 - 57.2(5)


Xbb
30.84
31.61
30.9(10)


Xcc
27.16
26.95
26.3(10)


|Xab|
36.24
34.08



 









RMS
0.7 (1.8 %)
1.0 (2.5 %)




RSD
0.49 (1.1 %)
0.49 (1.1 %)



 









 








 








   








Table 4. Chlorine nqcc's in ClC(=O)OCH2D (MHz).  Calculation was made on the rs and re structures.
   











Calc /rs
Calc /re
Expt. [1]
   








35Cl Xaa - 56.53 -
 57.17
 - 56.2(5)


Xbb
29.38
30.22
29.6(10)


Xcc
27.16
26.95
26.6(10)


|Xab|
37.95
35.85



 









RMS
0.4 (1.1 %)
0.7 (1.8 %)




RSD
0.49 (1.1 %)
0.49 (1.1 %)



 









 








 













Table 5. Molecular structure parameters, partial rs [1] and re [2] (Å and degrees).
 





rs [1]     re [2]
 




Cl-C 1.73 1.7438(44)

C=O 1.19 1.1870(65)

O=C-O 1.36 1.3238(98)

O-CH3 1.43 1.4400(19)

CHs 1.07 1.0797(36)

CHa 1.08 1.0943(32)

ClC=O 126 123.50(99)

O=C-O 125
 127.49(75)

C-O-C 115
 113.42(21)

O-CHs 105
 105.29(31)

O-CHa 110
 109.90(3)

HaCHa 111


HsCHa 110


HaCOHa
120.16(30)







 








 








[1] J.R.Durig and M.G.Griffin, J.Mol.Spectrosc. 64,252(1977).

[2] P.Groner and R.D.Warren, J.Mol.Struct. 590,323(2001).

 








D. G. Lister and N. L. Owen, J.Chem.Soc. Faraday Trans. 2, 69, 1036(1973): Xaa = -58.8(2) and Xbb = 31.1(5) MHz.

 








 








CH3COCl HCOCl FCOCl


 








 








Table of Contents




Molecules/Chlorine




 








 













ClCO2CH3.html






Last Modified 14 Nov 2013