CH3CH2-O-CN













































Nitrogen


Nuclear Quadrupole Coupling Constants


in Ethyl cyanate


 








 








 

 





The microwave spectrum of trans ethyl cyanate has been observed and assigned by Sakaizumi et al. [1].  Rotational constants and dipole moments were determined.

 








Calculation of the 14N nqcc tensors was made here on ropt molecular structures given by B3LYP/cc-pVTZ and MP2/6-311+G(3df,3pd) optimizations, the latter with approximate equilibrium C-C and CN bond lengths.  These calculated nqcc's are given in Table 1.  Structure parameters in Z-matrix format are compared in Table 2, rotational constants in Table 3.  Dipole moments and quartic centrifugal distortion constants are given in Table 4.

 








In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.

RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of nitrogen efg's/nqcc's.

 








 








 








Table 1.  14N nqcc's in Ethyl cyanate (MHz).  Calculation was made on the B3LYP/cc-pVTZ and MP2/6-311+G(3df,3pd) ropt structures, the latter with approximate equilibrium C-C and CN bond lengths.
 










Calc /B3LYP
Calc /MP2
Expt.
 








Xaa -
 2.457
 -
 2.391



Xbb
1.749
1.682



Xcc
0.708
0.709



|Xab|
1.315
1.371












RSD
0.030 (1.3 %)
0.030 (1.3 %)












Xxx
2.126
2.101



Xyy
0.708
0.709



Xzz -
 2.834
 -
 2.810



ETA -
 0.500
 -
 0.495



Øz,a
16.00
16.98



Øa,CN
15.74
16.69



Øz,CN
  0.26
  0.29













 








 







 
 


Table 2. Ethyl cyanate.  B3LYP/cc-pVTZ and MP2/6-311+G(3df,3pd) ropt structure parameters (Å and degrees).  Approximate equilibrium C-C and CN bond lengths are given in parentheses.





 C
 C,1,B1
 H,1,B2,2,A1
 H,1,B3,2,A2,3,D1,0
 H,1,B4,2,A3,4,D2,0
 H,2,B5,1,A4,5,D3,0
 H,2,B6,1,A5,5,D4,0
 O,2,B7,1,A6,5,D5,0
 C,8,B8,2,A7,1,D6,0
 N,9,B9,2,A8,1,D7,0





B3LYP/cc-pVTZ
 MP2/6-311+G(3df,3pd)





 B1=1.50639545
 B2=1.0891654
 B3=1.09046893
 B4=1.0891654
 B5=1.089509
 B6=1.089509
 B7=1.47371443
 B8=1.28561314
 B9=1.15611135
 A1=110.94526318
 A2=109.26412229
 A3=110.94526318
 A4=112.46956362
 A5=112.46956362
 A6=107.2869241
 A7=115.65505678
 A8=147.26436858
 D1=119.46887731
 D2=119.46887731
 D3=57.49513751
 D4=-178.55738289
 D5=-60.53112269
 D6=180.
 D7=180.
  B1=1.50345662     (1.5022)
 B2=1.0868693
 B3=1.08821546
 B4=1.0868693
 B5=1.08853127
 B6=1.08853127
 B7=1.46113772
 B8=1.28855964
 B9=1.17421475     (1.1594)
 A1=110.56613033
 A2=109.27180901
 A3=110.56613033
 A4=112.40272026
 A5=112.40272026
 A6=106.75479557
 A7=113.66600898
 A8=146.00874243
 D1=119.57357922
 D2=119.57357922
 D3=57.47647898
 D4=-178.32932053
 D5=-60.42642078
 D6=180.
 D7=180.







 








 



Table 3. Ethyl cyanate.  Rotational Constants (MHz).  B3LYP/cc-pVTZ and MP2/6-311+G(3df,3pd) ropt, the latter with approximate equilibrium C-C and CN bond lengths.







B3LYP
  MP2
Expt [1]






A
  31204
 30728

B
    2516
   2559

C
    2398
   2434


 


















 




Table 4. Ethyl cyanate.  B3LYP/cc-pVTZ calculated Quartic Centrifugal Distortion Constants (kHz) and Dipole Moments (D).









B3LYP
Expt [1]







Delta_J
0.375


Delta_JK -
 5.79


Delta_K
347.


delta_J
0.0372


delta_K -
 2.64








D_J
0.377


D_JK -
 5.81


D_K
347.


d_1
 -
 0.0372


d_2
0.00135








|µa|
4.97
4.70(18)

|µb|
0.64
0.38(15)






















[1] T.Sakaizumi, H.Mure, O.Ohashi, I.Yamaguchi, J.Mol.Spectrosc. 138,375(1989).

 








 








Methyl cyanate CH3CH2-X-CN where X=S,Se



 








 








Table of Contents




Molecules/Nitrogen




 








 













CH3CH2OCN.html






Last Modified 17 Feb 2014