ClH2C-CH2OH




 






























 








 









Chlorine


Nuclear Quadrupole Coupling Constants

in 2-Chloroethanol

 








 








 








Calculation of the chlorine nqcc tensors in 2-chloroethanol was made on molecular structures given by MP2/6-311+G(3df,3pd) optimization with empirically corrected approximate equilibrium C-Cl and C-C bond lengths, and by MP2/aug-cc-pVTZ optimization also with empirically corrected approximate equilibrium C-Cl and C-C bond lengths.  Calculated nqcc's are compared with experimental values [1] in Tables 1 and 2.  Structure parameters are given in Z-Matrix format in Table 3, rotational constants and dipole moments in Table 4.

 








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.  Øz,CCl (degrees) is the angle the z-principal axis makes with the CCl bond axis.

 








RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  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.  35Cl nqcc's in 2-Chloroethanol (MHz).  Calculation was made on structures given by (1) MP2/6-311+G(3df,3pd) and (2) MP2/aug-cc-pVTZ optimization, each with approximate re C-Cl and C-C bond lengths.
   









Calc. (1)
Calc. (2)
Expt. [1]
   







Xaa - 19.27 - 18.77
 - 19.16(10)

Xbb - 12.77 - 13.32
 - 12.65(10)

Xcc
32.05
32.09
31.82(10)

Xab * - 49.25 - 49.29
50(2)

Xac *
14.88
14.77
14.7(3)

Xbc *
15.41
15.44
 - 14.0(10)

 







RMS
0.16 (0.78 %) 0.47 (2.2 %)


RSD
0.49 (1.1 %)
0.49 (1.1 %)



 







Xxx
33.01
32.93



Xyy
36.86
36.86



Xzz - 69.87
 - 69.79
 - 70.0(20)

ETA
0.0550
0.0562
0.02(3)

Øz,CCl
0.85
0.86



 








 








* The algebraic signs of the off-diagonal components depend on the orientation of the molecule with respect to a,b,c axes.  In this regard, calculated and experimental off-diagonal nqcc's can be brought into agreement by transformation: b --> -b or a --> -a and c --> -c.

 








 








   







Table 2.  37Cl nqcc's in 2-Chloroethanol (MHz).  Calculation was made on structures given by (1) MP2/6-311+G(3df,3pd) and (2) MP2/aug-cc-pVTZ optimization, each with approximate re C-Cl and C-C bond lengths.
   









Calc. (1)
Calc. (2)
Expt.
   







Xaa - 15.70 - 15.30
 - 15.84(10)

Xbb
- 9.61 -
 10.03
- 9.42(10)

Xcc
25.31
25.33
25.27(10)

Xab
 - 38.80 - 38.77



Xac
11.72
11.64



Xbc
12.00
12.02



 







RMS
0.14 (0.83 %) 0.47 (2.8 %)


RSD
0.44 (1.1 %)
0.44 (1.1 %)



 








 








 












Table 3.  2-Chloroethanol.  Structure parameters (Å and degrees).  Approximate re bond lenths are given in parentheses.





 Cl
 C,1,R1
 C,2,R2,1,A1
 O,3,R3,2,A2,1,D1,0
 H,4,R4,3,A3,2,D2,0
 H,3,R5,2,A4,1,D3,0
 H,3,R6,2,A5,1,D4,0
 H,2,R7,1,A6,3,D5,0
 H,2,R8,1,A7,3,D6,0











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






 R1=1.78219738   (1.7867)
 R2=1.51210362   (1.5104)
 R3=1.41022216
 R4=0.96215182
 R5=1.09291457
 R6=1.08929165
 R7=1.08598167
 R8=1.0867186
 A1=110.09482652
 A2=112.43595836
 A3=107.26954771
 A4=109.48916893
 A5=108.4236985
 A6=107.06276072
 A7=107.31747122
 D1=63.95663716
 D2=-59.63409202
 D3=-60.58830708
 D4=-178.78939566
 D5=120.56993904
 D6=-121.08036576
  R1=1.7921435     (1.7889)
 R2=1.51141363   (1.5098)
 R3=1.41458903
 R4=0.96539367
 R5=1.09353056
 R6=1.0902478
 R7=1.08638571
 R8=1.08716099
 A1=109.76377351
 A2=112.36352182
 A3=106.99111482
 A4=109.59066802
 A5=108.53672498
 A6=106.72701824
 A7=107.09039208
 D1=63.40574466
 D2=-58.64933989
 D3=-61.05150382
 D4=-179.37280851
 D5=120.55644685
 D6=-121.16051388



 








 













Table 4. 2-Chloroethanol-35Cl.  Rotational constants (MHz).  Calc(1) = MP2/6-311+G(3df,3pd) and Calc(2) = MP2/aug-cc-pVTZ optimization, each with approximate re C-Cl and C-C bond lengths.







Calc (1) Calc (2)     Expt. [1]






A 12 866.4
 12 759.8
 12 747.976(30)

B   3 538.9   3 560.4
   3 505.777(20)

C   3 011.2
   3 021.1
   2 981.276(20)






|µa|
   0.07
   0.10

|µb|   1.48
   1.53

|µc|   0.34
   0.32


 








 








[1] R.G.Azrak and E.B.Wilson, J.Chem.Phys. 52,5299(1970).

 








 








CH3Cl CH3CH2Cl CH2ClCHF2 CH3CCl3

CF2ClCH3 CF2ClCHF2 CF2ClCH2F CF2ClCF3

CF3Cl CH2ClCF3 CH2ClCH2F CH3CHFCl

 








 








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Molecules/Chlorine




 








 













ClH2CCH2OH.html






Last Modified 7 Jan 2014