C9H9N




 





 






























Nitrogen


Nuclear Quadrupole Coupling Constants


in 1-Methylindole


 








 








 








The microwave spectrum of 1-methylindole was assigned by Gurusinghe and Tubergen [1,2].

 








Calculation of the 14N nqcc tensor was made here on ropt molecular structures given by  B3LYP/cc-pVTZ and B3P86/6-31G(3d,3p) optimization.  Calculated and experimental nqcc's are compared in Table 1.  Structure parameters are given in Z-matrix format in Table 2, rotational constants 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.

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 1-Methylindole (MHz).  Calculation was made on molecular structures given by (1) B3LYP/cc-pVTZ and (2) B3P86/6-31G(3d,3p) optimization.
   









Calc. (1)
Calc. (2)
Expt. [1]
   







Xaa
1.724
1.693
1.730(9)

Xbb
1.835
1.820
1.862(7) *

Xcc -
 3.559
 -
 3.513
 -
 3.592(7) *

|Xab|
0.282
0.278












RMS
0.025 (1.0 %)
0.056 (2.3 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.492
1.471



Xyy
2.067
2.041



Xzz -
 3.559
 -
 3.513



ETA
0.161
0.162



 








 








* Derived here from experimental Xaa and Xbb - Xcc = 5.455(10) MHz.

 







 
 

Table 2.  1-Methylindole.  Optimized molecular structure parameters, ropt (Å and degrees).
 

B3LYP/cc-pVTZ  and  B3P86/6-31G(3d,3p)
 



 C
 C,1,B1
 C,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 C,4,B4,3,A3,2,D2,0
 C,5,B5,4,A4,3,D3,0
 C,1,B6,6,A5,5,D4,0
 C,7,B7,1,A6,6,D5,0
 N,2,B8,1,A7,6,D6,0
 H,3,B9,2,A8,1,D7,0
 H,4,B10,3,A9,2,D8,0
 H,5,B11,4,A10,3,D9,0
 H,6,B12,5,A11,4,D10,0
 H,7,B13,1,A12,6,D11,0
 H,8,B14,7,A13,1,D12,0
 C,9,B15,2,A14,1,D13,0
 H,16,B16,9,A15,2,D14,0
 H,16,B17,9,A16,2,D15,0
 H,16,B18,9,A17,2,D16,0


      B3LYP
         B3P86


 B1=1.41966702
 B2=1.39484673
 B3=1.38484316
 B4=1.40465132
 B5=1.38330361
 B6=1.43126707
 B7=1.36520708
 B8=1.37763106
 B9=1.08165133
 B10=1.08170256
 B11=1.08177068
 B12=1.08232983
 B13=1.07638068
 B14=1.07716044
 B15=1.44446122
 B16=1.08733428
 B17=1.09196722
 B18=1.09196722
 A1=122.13526131
 A2=117.56568204
 A3=121.21161876
 A4=121.12722443
 A5=134.46416519
 A6=106.8658327
 A7=107.79102933
 A8=121.58722152
 A9=119.40815174
 A10=119.18156485
 A11=120.48374951
 A12=127.23287441
 A13=129.82780313
 A14=125.55882545
 A15=109.09321807
 A16=111.13820156
 A17=111.13820156
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=180.
 D9=180.
 D10=180.
 D11=0.
 D12=180.
 D13=180.
 D14=180.
 D15=-60.47120422
 D16=60.47120422
  B1=1.41878682
 B2=1.39418467
 B3=1.38480815
 B4=1.40446945
 B5=1.38361733
 B6=1.42993286
 B7=1.36628458
 B8=1.3745541
 B9=1.08503824
 B10=1.08481875
 B11=1.08485342
 B12=1.08528621
 B13=1.07945761
 B14=1.08059936
 B15=1.43926755
 B16=1.08992777
 B17=1.09435133
 B18=1.09435133
 A1=122.37476282
 A2=117.3927095
 A3=121.24316847
 A4=121.19537888
 A5=134.54730317
 A6=106.76383883
 A7=107.80745418
 A8=121.58812178
 A9=119.38213887
 A10=119.15533876
 A11=120.52454146
 A12=127.31270399
 A13=130.07331513
 A14=125.36366889
 A15=109.03097701
 A16=111.10002617
 A17=111.10002617
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=180.
 D9=180.
 D10=180.
 D11=0.
 D12=180.
 D13=180.
 D14=180.
 D15=-60.49876387
 D16=60.49876387





 














Table 3.  1-Methylindole.  Rotational Constants (MHz).







ropt(1) = B3LYP/cc-pVTZ optimization.

ropt(2) = B3P86/6-31G(3d,3p) optimization.








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







A
 2670.2
 2670.1
 2651.1270(15)

B
 1306.7
 1311.6
 1305.2571(7)

C
   882.2
   884.4
   879.7833(4)



















[1] R.Gurusinghe and M.Tubergen, J.Chem.Phys. A 120(20),3491(2016).

[2] R.Gurusinghe and M.Tubergen, Abstract RJ03, 69th International Symposium on Molecular Spectroscopy, Champaign-Urbana, Ill. 2014.

 








 








Indole
Pyrrole N-Methylpyrrole
 Carbazole

3-Methylindole
 2-Methylindole 5-Methylindole



4-Methylindole
 6-Methylindole 7-Methylindole



 








 








Table of Contents




Molecules/Nitrogen




 








 













1MeIndole.html






Last Modified 4 May 2016