CH3CH2-O-C(=O)Cl





 


















 










Chlorine


Nuclear Quadrupole Coupling Constants

in Ethyl Chloroformate


 








 








For each conformer of ethyl chloroformate shown below, calculation of the chlorine nqcc tensors was made on a molecular structure given by MP2/6-311+G(3df,3pd) optimization with empirically corrected approximate equilibrium C-C, C=O, and CCl bond lengths.  These calculated nqcc's are given in Tables 1 and 2.  Structure parameters are given in Z-Matrix format in Table 3, rotational constants and dipole moments in Table 4.


 








syn-anti


syn-gauche



At the



MP2/6-311+G(3df,3pd)

level of theory,


Esyn-anti < Esyn-gauche


by 0.006 kJ/mol






O=COC Dihedral = 0o


O=COC Dihedral = 1.9o

COCC Dihedral = 180o

COCC Dihedral = 80.5o











In Tables 1 and 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.  ETA = (Xxx - Xyy)/Xzz.  (degrees) is the angle between its subscripted parameters.


RSD is the calibration residual standard deviation of the B1LYP/TZV(3df,2p) model for calculation of the chlorine efg's/nqcc's.

 









 








 
 
 






Table 1.  Chlorine nqcc tensor in syn-anti ethyl chloroformate (MHz).  Calculation was made on a molecular structure given by MP2/6-311+G(3df,3pd) optimization with approximate re C-C, C=O, and C-Cl bond lengths.

 
 









Calc.

Expt.

 
 






35Cl Xaa -
34.05





Xbb
  7.15





Xcc
26.90





Xab

52.44





 






RSD
0.49 (1.1 %)





 






Xxx
42.89





Xyy
26.90




Xzz -
69.79





ETA -
0.229





z,a
34.27





a,CCl
34.98





z,CCl
  0.71




 







37Cl Xaa -
27.53





Xbb
  6.33





Xcc
21.20





Xab
41.05













RSD

0.44 (1.1 %)













 








 








 
 






Table 2.  Chlorine nqcc tensor in syn-gauche ethyl chloroformate (MHz).  Calculation was made on a molecular structure given by MP2/6-311+G(3df,3pd) optimization with approximate re C-C, C=O, and C-Cl bond lengths.

 
 









Calc.

Expt.

 
 






35Cl Xaa -
54.22





Xbb
30.42





Xcc
23.80





Xab
-
34.70





Xac
15.62





Xbc
  7.15





 






RSD
0.49 (1.1 %)





 






Xxx
42.96





Xyy
26.80





Xzz -
69.76





ETA -
0.232





z,CCl
0.71




 







37Cl Xaa -
43.04





Xbb
24.18





Xcc
18.86





Xab -
27.09





Xac
12.10





Xbc
  5.53













RSD

0.44 (1.1 %)












 








 


















Table 3.  Ethyl chloroformate.  MP2/6-311+G(3df,3pd) optimized structure parameters ( and degrees).  Approximate re bond lenths are given in parentheses.










syn-anti

syn-gauche

        C
        O,1,B1
        O,1,B2,2,A1
        C,3,B3,1,A2,2,D1,0
        C,4,B4,3,A3,1,D2,0
        H,4,B5,3,A4,1,D3,0
        H,4,B6,3,A5,1,D4,0
        H,5,B7,4,A6,3,D5,0
        H,5,B8,4,A7,3,D6,0
        H,5,B9,4,A8,3,D7,0
        Cl,1,B10,2,A9,3,D8,0












 B1=1.19490166    (1.1903)
 B2=1.32493349
 B3=1.45006305
 B4=1.50593089    (1.5046)
 B5=1.08810906
 B6=1.08810906
 B7=1.08825073
 B8=1.08708979
 B9=1.08708979
 B10=1.74382794   (1.7480)
 A1=127.65260577
 A2=113.8498172
 A3=106.57593516
 A4=108.23208944
 A5=108.23208944
 A6=109.38362694
 A7=110.67632437
 A8=110.67632437
 A9=123.44566966
 D1=0.
 D2=180.
 D3=58.76567359
 D4=-58.76567359
 D5=180.
 D6=-60.36313122
 D7=60.36313122
 D8=180.

 B1=1.1952851     (1.1907)
 B2=1.3249287
 B3=1.45102263
 B4=1.50993788    (1.5084)
 B5=1.0872434
 B6=1.0854498
 B7=1.08889359
 B8=1.08682389
 B9=1.08747059
 B10=1.7436971     (1.7479)
 A1=127.94428865
 A2=114.34414129
 A3=110.66659355
 A4=108.52112544
 A5=103.53770942
 A6=109.35518473
 A7=110.69327065
 A8=110.47087971
 A9=123.27576637
 D1=1.92080453
 D2=80.51834448
 D3=-42.60686186
 D4=-159.33932308
 D5=176.2883134
 D6=-64.38303769
 D7=56.88682779
 D8=-179.74391251





























Table 4. Ethyl chloroformate, 35Cl species, rotational constants (MHz) and dipole moments (D).








________syn-anti_________ _______syn-gauche________


Calc
 Expt
Calc
 Expt







A 6917.6

7002.5


B 1544.8

1626.7


C 1283.0

1477.0








|a|
 2.77

 2.42


|b|  0.89

 1.28


|c|  0 (symm)

 0.22



 








 








Y.A.Tobn, H.E.Di Loreta, C.O.Della Vdova, and R.M.Romano, J.Mol.Struct. 881,139(2008): IR


N.S.True and R.K.Bohn, OSU International Symposium on Molecular Spectroscopy, 1975: For 35Cl species of syn-anti, B + C = 2819(3) MHz; and for syn-gauche, B + C = 3061(3) MHz.  Esyn-anti < Esyn-gauche  by 0.0(1) kcal/mol.

 








 








Vinyl Chloroformate
S-Methylchlorothioformate
Methyl Chloroformate


Ethyl Cyanoformate





 








 








Table of Contents




Molecules/Chlorine




 








 













CH3CH2OCOCl.html






Last Modified 18 Jan 2014