C9H9N




 





 






























Nitrogen


Nuclear Quadrupole Coupling Constants


in 3-Methylindole


 








 








 








The microwave spectrum of 3-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 3-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
1.713
1.682
1.783(5)

Xbb
1.812
1.818
1.713(4) *

Xcc -
 3.525
 -
 3.500
 -
 3.496(4) *

|Xab|
0.020
0.020












RMS
0.072 (3.1 %)
0.084 (3.6 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.709
1.679



Xyy
1.816
1.821



Xzz -
 3.525
 -
 3.500



ETA
0.030
0.041



 








 








* Derived here from experimental Xaa and Xbb - Xcc = 5.209(5) MHz.

 







 
 

Table 2.  3-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,8,B13,7,A12,1,D11,0
 H,9,B14,2,A13,1,D12,0
 C,7,B15,1,A14,6,D13,0
 H,16,B16,7,A15,1,D14,0
 H,16,B17,7,A16,1,D15,0
 H,16,B18,7,A17,1,D16,0


      B3LYP
         B3P86


 B1=1.41797381
 B2=1.39347
 B3=1.38461831
 B4=1.40466455
 B5=1.38360577
 B6=1.43858546
 B7=1.36635269
 B8=1.37434695
 B9=1.08245761
 B10=1.08178196
 B11=1.08178353
 B12=1.08239568
 B13=1.07736021
 B14=1.00275712
 B15=1.49403168
 B16=1.09307719
 B17=1.09307719
 B18=1.09020921
 A1=122.19748779
 A2=117.59668951
 A3=121.19837608
 A4=121.05960069
 A5=133.77512412
 A6=106.22979334
 A7=107.08824279
 A8=121.39377675
 A9=119.41555133
 A10=119.20154155
 A11=120.34437003
 A12=129.34964762
 A13=125.60886727
 A14=126.74809078
 A15=111.62264588
 A16=111.62264588
 A17=111.1827846
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=180.
 D9=180.
 D10=180.
 D11=180.
 D12=180.
 D13=0.
 D14=-59.80899315
 D15=59.80899315
 D16=180.
  B1=1.4170632
 B2=1.3933325
 B3=1.38470127
 B4=1.40442432
 B5=1.38368698
 B6=1.43664941
 B7=1.36779974
 B8=1.37263626
 B9=1.08532397
 B10=1.08486163
 B11=1.08485379
 B12=1.08556994
 B13=1.08046592
 B14=1.00464856
 B15=1.49052117
 B16=1.09529338
 B17=1.09529338
 B18=1.09240981
 A1=122.3090373
 A2=117.44599139
 A3=121.26863265
 A4=121.09040539
 A5=133.73087321
 A6=106.16239879
 A7=107.0820375
 A8=121.4712814
 A9=119.36327504
 A10=119.18815854
 A11=120.46019636
 A12=129.45250103
 A13=125.48979947
 A14=126.80655045
 A15=111.63132069
 A16=111.63132069
 A17=111.16862946
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=180.
 D9=180.
 D10=180.
 D11=180.
 D12=180.
 D13=0.
 D14=-59.82319631
 D15=59.82319631
 D16=180.





 














Table 3.  3-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
 2626.4
 2628.0
 2603.724(4)

B
 1269.8
 1271.9
 1268.785(2)

C
   860.5
   861.7
   857.8098(2)



















[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

1-Methylindole 2-Methylindole 5-Methylindole



4-Methylindole 6-Methylindole 7-Methylindole



 








 








Table of Contents




Molecules/Nitrogen




 








 













3MeIndole.html






Last Modified 4 May 2016