CH3-NH-CH2CCH
























 






Nitrogen


Nuclear Quadrupole Coupling Constants


in N-Methyl Propargyl Amine


 








 








Calculation of the 14N nqcc's in N-methyl propargyl amine (CH3-NH-CH2CCH) was made here on ropt molecular structures given by MP2/^-311+G(3df,3pd) and B3LYP/6-311+G(3df,3pd) optimizations.











Calculated and experimental nqcc's [1] are compared in Table 1.  Structure parameters are given in Table 2, rotational constants and 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.  RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the efg's/nqcc's.











 








 








Table 1.  14N nqcc's in CH3-NH-CH2CCH (MHz).  Calculation was made on the (1) MP2/6-311+G(3df,3pd) and (2) B3LYP/6-311+G(3df,3pd) ropt structures.
 










Calc (1)
Calc (2)
Expt. [1]
 








Xaa -
 1.478
 -
 1.113
 -
 1.0(7)

Xbb -
 0.387
 -
 0.798
 -
 0.7(4)

Xcc
1.865
1.911
1.7

Xab -
 3.932 -
 4.106



Xac -
 1.328 -
 1.315



Xbc -
 0.851
 -
 0.995












RSD
0.030 (1.3 %)
0.030 (1.3 %)












Xxx
2.151
2.213



Xyy
3.094
3.205



Xzz -
 5.245
 -
 5.419



ETA
0.180
0.183













 








 







 



Table 2. CH3-NH-CH2CCH: MP2/6-311+G(3df,3pd) and B3LYP/6-311+G(3df,3pd) ropt structure parameters (Å and degrees).






 N
 C,1,B1
 C,1,B2,2,A1
 H,1,B3,2,A2,3,D1,0
 H,2,B4,1,A3,3,D2,0
 H,3,B5,1,A4,2,D3,0
 H,2,B6,1,A5,3,D4,0
 H,3,B7,1,A6,2,D5,0
 H,3,B8,1,A7,2,D6,0
 C,2,B9,1,A8,3,D7,0
 C,10,B10,1,A9,2,D8,0
 H,11,B11,1,A10,2,D9,0


         MP2       B3LYP

 B1=1.45809151
 B2=1.45741676
 B3=1.0128266
 B4=1.08984453
 B5=1.08734895
 B6=1.09139932
 B7=1.08953006
 B8=1.09526693
 B9=1.47091724
 B10=1.21559483
 B11=1.06181907
 A1=112.46728273
 A2=108.50662048
 A3=108.58933575
 A4=109.12055782
 A5=107.98424259
 A6=108.77401992
 A7=113.67305371
 A8=114.53877836
 A9=144.6264303
 A10=156.97540737
 D1=120.98192371
 D2=177.76691313
 D3=178.32279829
 D4=62.00511357
 D5=-64.08399213
 D6=56.57765057
 D7=-59.82161589
 D8=179.07203122
 D9=179.46523629
  B1=1.46078441
 B2=1.45892205
 B3=1.01224552
 B4=1.09177171
 B5=1.08912983
 B6=1.09295721
 B7=1.0913237
 B8=1.09727059
 B9=1.47094313
 B10=1.20039867
 B11=1.0613914
 A1=114.41402651
 A2=109.33591033
 A3=108.32715154
 A4=109.04235764
 A5=108.16026215
 A6=109.19939462
 A7=114.13626453
 A8=115.62992974
 A9=146.05091036
 A10=157.45461736
 D1=123.91165662
 D2=174.84370349
 D3=178.90221653
 D4=59.91331572
 D5=-63.67469382
 D6=57.34137136
 D7=-62.66110001
 D8=178.72291003
 D9=179.27993647



 













Table 3. CH3-NH-CH2CCH:  MP2/6-311+G(3df,3pd), B3LYP/6-311+G(3df,3pd), and Experimental Rotational Constants (MHz) and Dipole Moments * (D).







MP2 B3LYP   Expt [1]






A
 10656.
 11019.
 10763.1583(29)

B
   3327.
   3195.
   3266.38516(91)

C
   2772.
   2703.
   2735.02663(78)






|µa|
 0.24
 0.16
 0.209(5)

|µb| 0.51
 0.50
 0.480(10)

|µc| 0.29
 0.29
 0.267(4)

|µtot| 0.64
 0.60
 0.588(10)






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



 








 








[1]  K.-M.Marstokk and H.Møllendal, Acta Chem. Scand. A 39,483(1985).

 








 








CH3-NH-CH3 CH3CH2-NH-CH2CH3













 








 








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Last Modified 20 Jan 2016