Nicotinic Acid


















 




 


cis-Nicotinic Acid
trans-Nicotinic Acid

 








 








Nitrogen


Nuclear Quadrupole Coupling Constants

in Nicotinic Acid


(Pyridine-3-Carboxylic Acid)

 








 








 








Calculation of the N nqcc's in nicotinic acid was made here on molecular structures derived by B3P86/6-31G(d,p) and B3P86/6-31G(3d,3p) optimizations.  Calculated and experimental nqcc's [1] are compared in Tables 1 and 2.  Structure parameters are given in Table 3, rotational constants in Table 4.

 








In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.

RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percent of the average of the absolute experimental nqcc's).  RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of nitrogen nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's.

 








 








   








Table 1.   14N nqcc's in cis-Nicotinic Acid (MHz).  Calculation was made on (1) B3P86/6-31G(d,p) and (2) B3P86/6-31G(3d,3p) optimized structures.
   










Calc. (1)

Calc. (2)
Expt. [1]
   








Xaa
0.003
0.002
0.0361(87)

Xbb - 3.429 - 3.446 - 3.4585(96)

Xcc
3.426
3.444
3.4223(96)

|Xab|
2.710
2.700



 







RMS
0.026 (1.1 %)
0.025 (1.1 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.494
1.481



Xyy
3.426
3.444



Xzz - 4.920 - 4.926



ETA
0.392
0.399



Øz,a
61.17
61.28



Øa,bi *
61.00
61.11



Øz,bi 
  0.18
  0.17



 








 








* "bi" is the bisector of the CNC angle.

 








 








   








Table 2.   14N nqcc's in trans-Nicotinic Acid (MHz).  Calculation was made on (1) B3P86/6-31G(d,p) and (2) B3P86/6-31G(3d,3p) optimized structures.
   










Calc. (1)

Calc. (2)
Expt. [1]
   








Xaa - 0.172 - 0.193 - 0.1907(83)

Xbb - 3.279 - 3.274 - 3.2621(91)

Xcc
3.451
3.467
3.4527(91)

|Xab|
2.809
2.814



 







RMS
0.015 (0.63 %)
0.011 (0.48 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.484
1.475



Xyy
3.451
3.467



Xzz - 4.935 - 4.942



ETA
0.398
0.403



Øz,a
59.47
59.35



Øa,bi *
59.53
59.42



Øz,bi 
  0.06
  0.07



 








 








* "bi" is the bisector of the CNC angle.

 








 



Table 3.  Nicotinic Acid.  Selected structure parameters (Å and degrees).  Complete structures are given here in Z-matrix format.
 




ropt (1) = B3P86/6-31G(d,p) optimization.

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



cis-Nicotinic Acid
ropt (1) ropt (2)
 

N(1)C(2) 1.3328 1.3309
C(2)C(3) 1.3982
1.3960
C(3)C(4)
1.3952
1.3931
C(4)C(5) 1.3865
1.3841
C(5)C(6) 1.3942
1.3920
C(6)N(1) 1.3359 1.3339
C(6)NC(2) 117.21 117.19
NC(2)C(3) 123.43 123.43
C(2)C(3)C(4) 118.52 118.56
C(3)C(4)C(5) 118.52 118.46
C(4)C(5)C(6) 118.32 118.37
C(5)C(6)N 123.99 123.98


C(3)C
1.4805
1.4792


C=O
1.2123
1.2077


C--O
1.3476
1.3466
 
O--H
0.9698
0.9679
 




 




trans-Nicotinic Acid
ropt (1) ropt (2)



N(1)C(2) 1.3315 1.3294
C(2)C(3) 1.3983
1.3964
C(3)C(4) 1.3955
1.3933
C(4)C(5) 1.3879
1.3856
C(5)C(6) 1.3935
1.3911
C(6)N(1) 1.3365 1.3348
C(6)NC(2) 117.07 117.09
NC(2)C(3) 123.64 123.60
C(2)C(3)C(4) 118.50 118.53
C(3)C(4)C(5) 118.32 118.32
C(4)C(5)C(6) 118.48 118.48
C(5)C(6)N 123.98 123.97


C(3)C
1.4799
1.4788


C=O
1.2117
1.2071


C--O
1.3496
1.3485


O--H
0.9698
0.9679
 





 








 



Table 4.  Nicotinic Acid.  Rotational Constants (MHz).  Normal Species.
 




ropt (1) = B3P86/6-31G(d,p) optimization.

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




cis-Nicotinic Acid







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






A   3961.1   3974.2 3944.2182(12)

B   1248.7   1252.1 1245.13484(35)

C     949.4     952.1   947.00712(20)
 




trans-Nicotinic Acid







A   3963.8   3977.4 3947.9594(11)

B   1247.5   1250.7 1243.65955(32)

C     948.9     951.5   946.40083(18)


 








 








[1] S.Mata, I.Peña, C.Cabezas, J.C.López, and J.L.Alonso, J.Mol.Spectrosc. 280,91(2012).


 








 








Pyridine Isonicotinic Acid
Picolinic Acid




Pyridine-3-Carbaldehyde







 








 








Table of Contents




Molecules/Nitrogen




 








 













nicotinic_acid.html






Last Modified 21 August 2012