1,6-Naphthyridine

























 





 








Nitrogen

Nuclear Quadrupole Coupling Constants

in 1,6-Naphthyridine

 








 








 








MW and IR spectra for 1,6-Naphthyridine were recorded by Gruet et al. [1].  Accurate ground state rotational parameters - including 14N nqcc's - were determined from analysis of the microwave spectrum.

 








Calculation of the nitrogen nqcc tensors was made here on molecular structures given by B3P86/6-31G(d,p) and B3P86/6-31G(3d,3p) optimization.  These calculated nqcc's are compared with experimental nqcc's in Tables 1 and 2.  Structure parameters are given in Z-matrix format 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.  ETA = (Xxx - Xyy)/Xzz.   Ø (degrees) is the angle between its subscripted parameters.

RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental 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(1) nqcc's in 1,6-Naphthyridine (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
1.543
1.534
1.5191(18)

Xbb - 4.686 - 4.691 -
 4.6809(12)

Xcc
3.143
3.157
3.1618

|Xab|
0.246
0.253



 







RMS
0.018 (0.58 %)
0.011 (0.35 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.553
1.544



Xyy
3.143
3.157



Xzz - 4.695 - 4.701



ETA
0.338
0.343



Øz,a
87.74
87.68



Øa,bi
90.82
90.86



Øz,bi*
  3.08
  3.18



 








 








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

 








 








   







Table 2.  14N(6) nqcc's in 1,6-Naphthyridine (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 - 3.625 - 3.636 -
 3.6392(15)

Xbb
0.211
0.208
0.2234(17)

Xcc
3.414
3.428
3.4158

|Xab|
2.566
2.558



 







RMS
0.011 (0.44 %)
0.012 (0.48 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx
1.497
1.485



Xyy
3.414
3.428



Xzz - 4.911 - 4.913



ETA
0.390
0.395



Øz,a
26.61
26.54



Øa,bi
28.66
28.66



Øz,bi*
  2.05
  2.12



 








 








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

 








 



Table 3. 1,6-Naphthyridine.  Structure Parameters (Å and degrees).
 




 N
 C,1,R1
 C,2,R2,1,A1
 C,3,R3,2,A2,1,D1,0
 C,4,R4,3,A3,2,D2,0
 C,5,R5,4,A4,3,D3,0
 N,6,R6,5,A5,4,D4,0
 C,7,R7,6,A6,5,D5,0
 C,8,R8,7,A7,6,D6,0
 C,5,R9,4,A8,3,D7,0
 H,2,R10,1,A9,10,D8,0
 H,3,R11,2,A10,1,D9,0
 H,4,R12,3,A11,2,D10,0
 H,6,R13,5,A12,4,D11,0
 H,9,R14,8,A13,7,D12,0
 H,8,R15,7,A14,6,D13,0





  B3P86/6-31G(d,p) opt
 B3P86/6-31G(3d,3p) opt






 R1=1.31492812
 R2=1.41633434
 R3=1.37137072
 R4=1.41250047
 R5=1.41753563
 R6=1.31289916
 R7=1.35874384
 R8=1.37342199
 R9=1.42205395
 R10=1.08932497
 R11=1.08464477
 R12=1.08676389
 R13=1.09081788
 R14=1.08424777
 R15=1.08705415
 A1=124.79924427
 A2=118.66531659
 A3=118.59818696
 A4=123.87936229
 A5=124.13037719
 A6=117.34889212
 A7=124.26579247
 A8=118.20372663
 A9=116.07062909
 A10=119.74894887
 A11=121.58695174
 A12=118.97168539
 A13=121.99553192
 A14=115.29338711
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=0.
 D6=0.
 D7=0.
 D8=180.
 D9=180.
 D10=180.
 D11=0.
 D12=180.
 D13=180.
  R1=1.31260842
 R2=1.41435513
 R3=1.36889083
 R4=1.41055187
 R5=1.41594546
 R6=1.31076411
 R7=1.35743362
 R8=1.37094537
 R9=1.4188397
 R10=1.08893784
 R11=1.08399806
 R12=1.08598547
 R13=1.09017221
 R14=1.08363495
 R15=1.08649156
 A1=124.78831373
 A2=118.7010846
 A3=118.56131879
 A4=123.79500007
 A5=124.11850196
 A6=117.29962815
 A7=124.3096893
 A8=118.25314352
 A9=116.0162935
 A10=119.69172932
 A11=121.58122421
 A12=118.98986424
 A13=121.83827904
 A14=115.20463797
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=0.
 D6=0.
 D7=0.
 D8=180.
 D9=180.
 D10=180.
 D11=0.
 D12=180.
 D13=180.







 








 



Table 4.  1,6-Naphthyridine.  Rotational Constants (MHz).
 




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

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






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






A      3242
      3251
 3227.104274(70)

B      1281
      1284
 1276.297178(30)

C        918
        921   914.802113(21)

 




 








 








[1] S.Gruet, M.Goubet, and O.Pirali, J.Chem.Phys. 140,234308(2014); Abstract TA11, 69th International Symposium on Molecular Spectroscopy, Champaign-Urbana, Ill., 2014.

 








 








Pyridine Quinoline and Isoquinoline

 








 








Table of Contents




Molecules/Nitrogen




 








 













16naphthyridine.html






Last Modified 15 July 2014