CH3CH2CN





 






 






 






 








Nitrogen

Nuclear Quadrupole Coupling Constants


in Ethyl Cyanide


 








 








 








Calculation of the nitrogen nqcc's in ethyl cyanide was made here on the substitution  structure of Heise et al. [1], and on an approximate equilibrium ~re structure given by MP2/aug-cc-pVTZ optimization with empirically corrected bond lengths.  These are compared with the experimental nqcc's [1-4] in Tables 1-8.  Molecular structure parameters are given in Table 9.

 








Calculation was made also on each of several molecular structures reported by Demaison et al. [5].  See PDF.

 








In Tables 1 - 8, 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 calculated and experimental nqcc's (percentage of average experimental nqcc).  RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's.

 








 








   







Table 1.  14N nqcc's in CH3CH2CN (MHz).  Calculation was made on the ~re and rs [1] structures.
   









Calc / ~re
Calc / rs
Expt. [2]
   







Xaa - 3.349 - 3.322 - 3.3572(18)

Xbb
1.278
1.278
1.2982(39)

Xcc
2.070
2.044
2.0590(39)

|Xab|
2.180
2.165



 







RMS
0.014 (0.63 %) 0.025 (1.1 %)


RSD
0.030 (1.3 %) 0.030 (1.3 %)



 







Xxx
2.144
2.136



Xyy
2.070
2.044



Xzz - 4.214 - 4.181



ETA - 0.017 - 0.022



Øz,a
21.65
21.63



Øa,CN
21.92
21.99



Øz,CN
  0.27
  0.36



 








 








 








   







Table 2.  14N nqcc's in CH3CH2CN (MHz).  Calculation was made on the ~re and rs [1] structures.
   









Calc / ~re
Calc / rs
Expt. [3]
   







Xaa - 3.349 - 3.322 - 3.309(33)

Xbb
1.278
1.278
1.265(13)

Xcc
2.070
2.044
2.044(20)

|Xab|
2.180
2.165



 







RMS
0.028 (1.3 %) 0.011 (0.48 %)


RSD
0.030 (1.3 %) 0.030 (1.3 %)



 







Xxx
2.144
2.136



Xyy
2.070
2.044



Xzz - 4.214 - 4.181



ETA - 0.017 - 0.022



Øz,a
21.65
21.63



Øa,CN
21.92
21.99



Øz,CN
  0.27
  0.36



 







   








 








   







Table 3.  14N nqcc's in CH3CD2CN (MHz).  Calculation was made on the ~re and rs [1] structures.
   









Calc / ~re
Calc / rs
Expt. [1]
   







Xaa - 3.441 - 3.412 - 3.449(16)

Xbb
1.370
1.368
1.399(15)

Xcc
2.070
2.044
2.050(17)

|Xab|
2.078
2.064
2.01(18)

 







RMS
0.021 (0.90 %) 0.028 (1.2 %)



RSD
0.030 (1.3 %) 0.030 (1.3 %)



 








 








 








   







Table 4.  14N nqcc's in CD3CH2CN (MHz).  Calculation was made on the ~re and rs [1] structures.
   









Calc / ~re
Calc / rs
Expt. [1]
   







Xaa - 3.193 - 3.166 - 3.209(17)

Xbb
1.123
1.122
1.150(16)

Xcc
2.070
2.044
2.059(18)

|Xab|
2.334
2.319
2.27(12)

 







RMS
0.019 (0.89 %) 0.031 (1.4 %)


RSD
0.030 (1.3 %) 0.030 (1.3 %)


 








 








 








   







Table 5.  14N nqcc's in 13CH3CH2CN (MHz).  Calculation was made on the ~re and rs [1] structures.
   









Calc / ~re
Calc / rs
Expt. [1]
   







Xaa - 3.311 - 3.285 - 3.290(11)

Xbb
1.241
1.241
1.242(10)

Xcc
2.070
2.044
2.048(12)

|Xab|
2.220
2.204



 







RMS
0.018 (0.81 %) 0.004 (0.17 %)


RSD
0.030 (1.3 %) 0.030 (1.3 %)


 








 








 








   







Table 6.  14N nqcc's in CH313CH2CN (MHz).  Calculation was made on the ~re and rs [1] structures.
   









Calc / ~re
Calc / rs
Expt. [1]
   







Xaa - 3.368 - 3.341 - 3.377(21)

Xbb
1.298
1.297
1.334(17)

Xcc
2.070
2.044
2.043(19)

|Xab|
2.159
2.144



 







RMS
0.026 (1.2 %) 0.030 (1.3 %)


RSD
0.030 (1.3 %) 0.030 (1.3 %)


 








 








 








   







Table 7. 14N nqcc's in CH3CH213CN (MHz).  Calculation was made on the ~re and rs [1] structures.
   









Calc / ~re
Calc / rs
Expt. [1]
   







Xaa - 3.344 - 3.317 - 3.349(11)

Xbb
1.273
1.273
1.297(10)

Xcc
2.070
2.044
2.052(12)

|Xab|
2.186
2.170



 







RMS
0.018 (0.83 %) 0.024 (1.0 %)


RSD
0.030 (1.3 %) 0.030 (1.3 %)


 








 








 








   







Table 8.  14N nqcc's in CD3CD2CN (MHz).  Calculation was made on the ~re and rs [1] structures.
   









Calc / ~re
Calc / rs
Expt. [4]
   







Xaa - 3.270 - 3.241 - 3.213(20)

Xbb
1.200
1.197
1.168(20)

Xcc
2.070
2.044
2.045(20)

|Xab|
2.261
2.248



 







RMS
0.040 (1.9 %) 0.023 (1.1 %)


RSD
0.030 (1.3 %) 0.030 (1.3 %)


 








 








 








 


Table 8.  Molecular structure parameters, ~re and rs [1] (Å and degrees).  Hs lies in symmetry plane.  Complete structures are given here in Z-matrix format (Gaussian input file).
 




   ~re rs [1]





NC(3) 1.1560 1.159(1)

C(3)C(2) 1.4611 1.459(1)

C(2)C(1) 1.5272 1.537(1)

C(2)H 1.0899 1.094(1)

C(1)Hs 1.0881 1.079(18)

C(1)Ha 1.0878 1.091(1)

NC(3)C(2) 178.68 178.73(22)

C(3)C(2)C(1) 111.64 111.98(10)

C(1)C(2)H 110.73 110.62(3)

C(2)C(1)Hs 109.88 111.08(237)

C(2)C(1)Ha 110.67 110.47(2)


 








 








[1] H.M.Heise, H.Lutz, and H.Dreizler, Z.Naturforsch. 29a,1345 (1974); H.Mäder, H.M.Heise, and H.Dreizler, Z.Naturforsch. 29a,164 (1973).

[2] A.Kraśnicki and Z.Kisiel, J.Mol.Spectrosc. 270,83(2011).

[3] Y.S.Li and M.D.Harmony, J.Chem.Phys. 50,3674(1969).

[4] Y.S.Li and J.R.Durig, J.Mol.Spectrosc. 54,296(1975).

[5] J.Demaison, L.Margulès, H.Mäder, M.Sheng, and H.D.Rudolph, J.Mol.Spectrosc. 252,169(2008).

 








 








CH3CH2NC CH3CH2Cl CH3CH2Br CH3CN

 








 








Table of Contents




Molecules/Nitrogen




 








 













CH3CH2CN.html






Last Modified 12 Sept 2011