C9H9N




 





 






























Nitrogen


Nuclear Quadrupole Coupling Constants


in 7-Methylindole


 








 








 








The microwave spectrum of 7-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 7-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
1.640
1.603
1.698(5)

Xbb
1.710
1.717
1.618(4)

Xcc -
 3.350
 -
 3.320
3.316(4)

|Xab|
0.004
0.003












RMS
0.067 (3.0 %)
0.079 (3.6 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.640
1.603



Xyy
1.710
1.717



Xzz -
 3.350
 -
 3.320



ETA
0.0210
0.0345



 








 








* Derived here from experimental Xaa and Xbb - Xcc = 4.935(5) MHz.

 







 
 

Table 2.  7-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,7,B9,1,A8,6,D7,0
 H,8,B10,7,A9,1,D8,0
 H,9,B11,2,A10,1,D9,0
 H,5,B12,4,A11,3,D10,0
 H,6,B13,5,A12,4,D11,0
 H,4,B14,3,A13,2,D12,0
 C,3,B15,2,A14,1,D13,0
 H,16,B16,3,A15,2,D14,0
 H,16,B17,3,A16,2,D15,0
 H,16,B18,3,A17,2,D16,0


      B3LYP
         B3P86


 B1=1.41670127
 B2=1.39953528
 B3=1.38667548
 B4=1.40571512
 B5=1.38100875
 B6=1.43304838
 B7=1.36473838
 B8=1.37821327
 B9=1.07653747
 B10=1.07655071
 B11=1.00274363
 B12=1.08186744
 B13=1.08211169
 B14=1.08305963
 B15=1.50330862
 B16=1.0940714
 B17=1.0940714
 B18=1.08895359
 A1=123.22748768
 A2=115.87907917
 A3=122.18041788
 A4=121.23399686
 A5=134.27439992
 A6=107.17176942
 A7=107.17644694
 A8=127.02057639
 A9=129.98241136
 A10=125.61897187
 A11=118.9849785
 A12=120.75146842
 A13=118.77984126
 A14=121.39066959
 A15=111.63133037
 A16=111.63133037
 A17=111.01908452
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=0.
 D8=180.
 D9=180.
 D10=180.
 D11=180.
 D12=180.
 D13=180.
 D14=-59.97200271
 D15=59.97200271
 D16=180.
  B1=1.41618084
 B2=1.39882124
 B3=1.38674475
 B4=1.40525137
 B5=1.3814704
 B6=1.43150593
 B7=1.36605018
 B8=1.37524861
 B9=1.07958664
 B10=1.07975386
 B11=1.0048377
 B12=1.08495219
 B13=1.08505073
 B14=1.08619517
 B15=1.49892725
 B16=1.09638098
 B17=1.09638098
 B18=1.09141664
 A1=123.37757826
 A2=115.81088934
 A3=122.17112727
 A4=121.27277282
 A5=134.38668151
 A6=107.07199383
 A7=107.2344235
 A8=127.14203481
 A9=130.13014216
 A10=125.44529582
 A11=118.99032034
 A12=120.75822619
 A13=118.65695391
 A14=121.40690621
 A15=111.69580839
 A16=111.69580839
 A17=110.93753463
 D1=0.
 D2=0.
 D3=0.
 D4=180.
 D5=180.
 D6=180.
 D7=0.
 D8=180.
 D9=180.
 D10=180.
 D11=180.
 D12=180.
 D13=180.
 D14=-60.03188165
 D15=60.03188165
 D16=180.





 














Table 3.  7-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
 2154.
 2155.
 2141.0265(13)

B
 1518.
 1521
 1515.2908(11)

C
   895.
   897.
   892.44164(7)









 








[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 6-Methylindole




 








 








Table of Contents




Molecules/Nitrogen




 








 













7MeIndole.html






Last Modified 4 May 2016