C8H9N


























 









Nitrogen


Nuclear Quadrupole Coupling Constants

in 2,3-Cyclopentenopyridine

 








 








 

 





Large amplitude motions in 2,3-Cyclopentenopyridine have been investigated by Fantoni and Caminati [1].  The microwave rotational spectra of  the ground and of several low energy vibrational excited states have been assigned.  14N nuclear quadrupole coupling constants, however, were not deteermined.

Thus, calculation of the 14N nuclear quadrupole coupling constant tensor was made here on an ropt molecular structure given by B3P86/6-31G(3d,3p) optimization.

This calculated nqcc tensor is given in Table 1; structure parameters in Table 2; rotational constants and electric dipole moments in Table 3; quartic centrifugal distortion constants in Table 4.

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.  Øz,bi (degrees) is the angle between the z-principal axis and the bisector of the CNC angle.   RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the efg's/nqcc's.

 








 








   






Table 1.  Nitrogen nqcc's in 2,3-Cyclopentenopyridine (MHz).  Calculation was made on B3P86/6-31G(3d,3p) ropt structure.
   









Calc
Expt
   






14N Xaa
1.513




Xbb -
 4.732




Xcc
3.219




Xab
0.071




Xac -
 0.084




Xbc
0.005



 







RSD
 0.030 (1.3 %)


 







Xxx
1.509




Xyy
3.224




Xzz -
 4.733




ETA
0.362




Øz,bi *
0.82



 







 








* Angle (degrees) between the z-principal axis of the nqcc tensor and the bisector of the CNC angle.

 








 


















Table 2.  2,3-Cyclopentenopyridine B3P86/6-31G(3d,3p) optimized structure parameters (Å and degrees).











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











 B1=1.54532992
 B2=1.53985444
 B3=1.50544586
 B4=1.3280745
 B5=1.33712998
 B6=1.39044374
 B7=1.39257501
 B8=1.38470916
 B9=1.0932392
 B10=1.0973679
 B11=1.09384774
 B12=1.09147308
 B13=1.09185205
 B14=1.0970143
 B15=1.08765487
 B16=1.08437334
 B17=1.0861259
 A1=105.64776471
 A2=103.06823264
 A3=124.44752851
 A4=115.9807775
 A5=123.98117283
 A6=119.15857962
 A7=117.65259617
 A8=113.25777163
 A9=110.08211531
 A10=109.10264477
 A11=112.56150959
 A12=113.62311124
 A13=111.57999009
 A14=115.93978666
 A15=119.87706617
 A16=120.79040325
 D1=25.09131729
 D2=165.05507882
 D3=179.32795336
 D4=-0.206807
 D5=-0.13189998
 D6=0.35374146
 D7=-42.93771711
 D8=76.35624752
 D9=92.14808742
 D10=-148.96053597
 D11=146.86395621
 D12=-92.37238947
 D13=179.60411283
 D14=179.69883572
 D15=-179.97692179













 













Table 3.  2,3-Cyclopentenopyridine.  Rotational Constants (MHz) and B3PW91/6-311+G(df,pd) Electric Dipole Moments (D) calculated on B3P86/6-31G(3d,3p) optimized structures.







 Calc.
    Expt [1]






A
 3596.8
 3568.454(3)

B
 1557.2
 1550.641(2)

C
 1116.7
 1112.907(2)






|µa|
 0.79
 0.7(1)

|µb| 2.17
 2.1(1)

|µc| 0.045
 0.0 (Fixed)



 








 













Table 4.  2,3-Cyclopentenopyridine.  Quartic Centrifugal Distortion Constants (kHz).  Calc = B3LYP/cc-pVTZ.







 Calc.
 Expt [1]






Delta_J
 0.038
 0.033(6)

Delta_JK 0.032
 0.043(8)

Delta_K 0.256
 0.210(32)

delta_j 0.009
 0.005(1)

delta_k 0.066
 0.021(18)







 








 








[1] A.C.Fantoni and W.Caminati, J.Mol.Spectrosc. 186,105(1997).

 








 








Pyridine
 Nicotine
 Anabasine
 Quinoline

 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 18 Nov 2013