C9H9N




 





 






























Nitrogen


Nuclear Quadrupole Coupling Constants


in 6-Methylindole


 








 








 








The microwave spectrum of 6-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 6-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
1.682
1.648
1.707(15)

Xbb
1.747
1.755
1.680(9)

Xcc -
 3.429
 -
 3.403
 -
 3.387(9)

|Xab|
0.039
0.042












RMS
0.048 (2.1 %)
0.056 (2.5 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.664
1.633



Xyy
1.765
1.769



Xzz -
 3.429
 -
 3.403



ETA
0.0296
0.0399



 








 








* Derived here from experimental Xaa and Xbb - Xcc = 5.066(9) MHz.

 







 
 

Table 2.  6-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,7,B10,1,A9,6,D8,0
 H,8,B11,7,A10,1,D9,0
 H,9,B12,2,A11,1,D10,0
 H,5,B13,4,A12,3,D11,0
 H,6,B14,5,A13,4,D12,0
 C,4,B15,3,A14,2,D13,0
 H,16,B16,4,A15,3,D14,0
 H,16,B17,4,A16,3,D15,0
 H,16,B18,4,A17,3,D16,0


      B3LYP
         B3P86


 B1=1.41571841
 B2=1.39498879
 B3=1.38639301
 B4=1.41196984
 B5=1.38074216
 B6=1.43354008
 B7=1.36453135
 B8=1.37604284
 B9=1.0833291
 B10=1.07651286
 B11=1.07650807
 B12=1.00298148
 B13=1.08306631
 B14=1.0826113
 B15=1.50732812
 B16=1.09254157
 B17=1.09254157
 B18=1.08978964
 A1=122.37419015
 A2=118.59253541
 A3=119.37808175
 A4=122.12303465
 A5=134.76940622
 A6=107.08714788
 A7=107.15937932
 A8=120.9740245
 A9=127.08754299
 A10=130.01985029
 A11=125.48976112
 A12=118.59247906
 A13=120.28569303
 A14=120.86338139
 A15=111.31736067
 A16=111.31736067
 A17=111.47913102
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=0.
 D9=180.
 D10=180.
 D11=180.
 D12=180.
 D13=180.
 D14=120.35749163
 D15=-120.35749163
 D16=0.
  B1=1.41556702
 B2=1.39445701
 B3=1.38662449
 B4=1.41155044
 B5=1.38090409
 B6=1.43179958
 B7=1.36568699
 B8=1.37376142
 B9=1.08630797
 B10=1.07956216
 B11=1.07973711
 B12=1.00483383
 B13=1.08620952
 B14=1.08546779
 B15=1.5030844
 B16=1.09483502
 B17=1.09483502
 B18=1.0922528
 A1=122.49943097
 A2=118.42257627
 A3=119.491168
 A4=122.140748
 A5=134.74803569
 A6=106.98277309
 A7=107.16255083
 A8=121.13813803
 A9=127.19422427
 A10=130.15777459
 A11=125.37397803
 A12=118.5007841
 A13=120.34251868
 A14=120.76119617
 A15=111.35775223
 A16=111.35775223
 A17=111.43620463
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=0.
 D9=180.
 D10=180.
 D11=180.
 D12=180.
 D13=180.
 D14=120.34082851
 D15=-120.34082851
 D16=0.





 














Table 3.  6-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
 3445.
 3442.
 3416.4461(9)

B
 1045.
 1047
 1042.1315(2)

C
   806.
   807.
   802.7492(9)









 








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

[2] R.Gurusinghe and M.Tubergen, Abstract WF08, 71st International Symposium on Molecular Spectroscopy, Champaign-Urbana, Ill. 2016.

 








 








Indole
Pyrrole N-Methylpyrrole
 Carbazole

3-Methylindole
 2-Methylindole 5-Methylindole 1-Methylindole

4-Methylindole 7-Methylindole




 








 








Table of Contents




Molecules/Nitrogen




 








 













6MeIndole.html






Last Modified 4 May 2016