CH3-NH-CH2CH3





 





 






























Nitrogen


Nuclear Quadrupole Coupling Constants


in  Methylaminoethane


 








 








 








Diagonal 14N nqcc's in methylaminoethane were determined by Penn and Boggs [1].


 









Calculation of the 14N nqcc tensor was made here on ropt molecular structures given by  mPW1PW91/6-311+G(3df,3pd) and MP2/6-311+G(df,pd) optimization.  Calculated and experimental nqcc's are compared in Table 1.  Structure parameters are given in Table 2, rotational constants and electric dipole moments in Table 3.


 








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


RMS is the root mean square difference between calculated and experimental diagonal nqcc's.  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 Methylaminoethane (MHz).  Calculation was made on molecular structures given by (1) mPW1PW91/6-311+G(3df,3pd) and (2) MP2/6-311+G(df,pd) optimization.
   










Calc. (1)

Calc. (2)
Expt. [1]

   








Xaa
2.811

2.767

2.82(9)


Xbb
0.976

0.883

0.88(13)


Xcc -
3.787
-
3.650
-
3.70(9)


|Xab|
0.292

0.289




|Xac|
0.528

0.523




|Xbc| -
2.945
-
2.960













RMS

0.075 (3.0 %)

0.042 (1.7 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
2.859

2.814




Xyy
2.379

2.343




Xzz -
5.238
-
5.157




ETA -
0.0916
-
0.0912




z,NH

70.50

69.61




 








 








 







 
 

Table 2.  Methylaminoethane.  Optimized molecular structure parameters, ropt ( and degrees).
 

mPW1PW91/6-311+G(3df,3pd)  and  MP2/6-311+G(df,pd)
 




 C
 C,1,B1
 H,1,B2,2,A1
 H,1,B3,2,A2,3,D1,0
 H,1,B4,2,A3,3,D2,0
 H,2,B5,1,A4,3,D3,0
 H,2,B6,1,A5,3,D4,0
 N,2,B7,1,A6,3,D5,0
 H,8,B8,2,A7,1,D6,0
 C,8,B9,2,A8,1,D7,0
 H,10,B10,8,A9,2,D8,0
 H,10,B11,8,A10,2,D9,0
 H,10,B12,8,A11,2,D10,0


    mPW1PW91
        MP2


 B1=1.51450186
 B2=1.08963825
 B3=1.09193857
 B4=1.08938299
 B5=1.10289538
 B6=1.09355372
 B7=1.44855941
 B8=1.01076874
 B9=1.44593343
 B10=1.08924432
 B11=1.10068426
 B12=1.09126386
 A1=110.88913303
 A2=111.04384317
 A3=110.6660078
 A4=109.65473287
 A5=109.68746023
 A6=111.29175838
 A7=109.47999394
 A8=113.40148349
 A9=109.90708534
 A10=113.93543347
 A11=109.51708296
 D1=119.52398587
 D2=-120.58127068
 D3=-56.60369382
 D4=59.63793782
 D5=178.70837056
 D6=54.08043423
 D7=177.28257608
 D8=-176.50998474
 D9=-54.80807661
 D10=65.59049757
 B1=1.5179435
 B2=1.09124414
 B3=1.09281349
 B4=1.09040066
 B5=1.10386586
 B6=1.09463489
 B7=1.45375464
 B8=1.01480248
 B9=1.45328974
 B10=1.09057735
 B11=1.10107669
 B12=1.09202778
 A1=110.81503664
 A2=110.62610507
 A3=110.14632526
 A4=109.75533233
 A5=109.8943412
 A6=110.82304862
 A7=108.75057609
 A8=112.4446784
 A9=109.71028175
 A10=113.52371688
 A11=108.93808908
 D1=119.62199035
 D2=-120.59623927
 D3=-57.74674472
 D4=59.40021566
 D5=178.00973523
 D6=55.51212015
 D7=176.94298242
 D8=-176.63527088
 D9=-54.8761526
 D10=65.35359957





 














Table 3.  Methylaminoethane.  Rotational Constants (MHz) and Dipole Moments * (D).







ropt(1) = mPW1PW91/6-311+G(3df,3pd) optimization.

ropt(2) = MP2/6-311+G(df,pd) optimization.








ropt(1) ropt(2) Expt [1]








A
26505.6
26222.9



B
  3948.9
  3953.4



C
  3698.9
  3701.0









|a| 0.014
0.027
0.00(3)


|b| 0.30
0.35
0.25(3)


|c| 0.93
0.96
0.84(1)


 





* B3PW91/6-311+G(df,pd) dipole moment calculation on ropt structures.













 








[1] R.E.Penn and J.E.Boggs, J.Mol.Spectrosc. 47,340(1973).


 








 








Dimethylamine
Diethylamine




 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 27 Nov 2013