




















Phthalazine












































Nitrogen



Nuclear
Quadrupole Coupling Constants 



in
Phthalazine 

































Nitrogen nqcc tensors in phthalazine
were calculated on a molecular structure optimized at the
B3P86/631G(3d,3p) level of theory. These calculated nqcc's are
compared with the experimental values of McNaughton et al. [1] in Table
1. Structure parameters are given in Table 2, rotational
constants and electric dipole moments in Table 3. 












In Table 1, subscripts a,b,c refer to
principal axes of the inertia tensor, subscripts x,y,z to principal
axes of the nqcc tensor. The nqcc yaxis is chosen coincident
with the inertia caxis, these are perpendicular to the plane of the
molecule. Ø (degrees) is the angle between its subscripted
parameters. ETA = (X_{xx}  X_{yy})/X_{zz}. 


RMS is the root mean square
difference between calculated and experimental nqcc's (percentage of
average experimental nqcc). RSD is the residual stand deviation
of calibration of the B3PW91/6311+G(df,pd) model for calculation of
the nqcc's. 































Table 1. Nitrogen
nqcc's in Phthalazine (MHz). Calculation was made
on the B3P86/631G(3d,3p) r_{opt} structure. 













Calc. 

Expt. [1] 










^{14}N(1,2) 
X_{aa} 
 
4.716 
 
4.72845(136) 



X_{bb} 

1.723 

1.8501 * 



X_{cc} 

2.993 

2.8783 * 



X_{ab} 
± 
2.470 
± 
2.350(94) 











RMS 

0.099 (3.1 %) 





RSD 

0.030 (1.3 %) 













X_{xx} 

2.561 





X_{yy} 

2.993 





X_{zz} 
 
5.554 





ETA 

0.0776 





Ø_{z,a} 

18.75 





Ø_{a,bi} 

30.25






Ø_{z,bi}** 

11.50

























* Calculated here from experimental X_{aa} and
X_{bb}  X_{cc} = 1.0283(30) MHz. 


** The zaxis makes an angle of
11.50^{o}
with the external bisector ('bi') of the NNC angle and tilts toward the
adjacent nitrogen atom. 

















Table 2. Phthalazine and
Pyridazine. Selected molecular structure parameters,
B3P86/631G(3d,3p) r_{opt} (Å and degrees).
The complete structure of phthalazine is given here in Zmatrix format. 








Phthalazine 
Pyridazine 







N(1)N(2) 
1.3569 
1.3251 


N(2)C(3) 
1.3089 
1.3314 


N(1)N(2)C(3) 
119.49 
119.44 





























Table 3.
Phthalazine, r_{opt}.
Rotational constants (MHz) and B3PW91/6311+G(df,pd) calculated
dipole moments (D). 









Calc. 

Expt. [1] 







A 

3291.67 

3263.94094(123) 

B 

1243.76 

1236.018430(35) 

C 

902.68 

896.743486(41) 







µ_{a} 

5.4 

























[1] D.McNaughton, P.D.Godfrey,
M.K.Jahn, D.A.Dewald, and J.U.Grabow, J.Chem.Phys. 134,154305(2011). 






















Pyridazine 
Quinazoline 
Quinoxaline 
1,10Phenanthroline 


Acridine 
Quinoline 
Isoquinoline 
Phenanthridine 






















Table of Contents 





Molecules/Nitrogen 






























Phthalazine.html 






Last
Modified 20 April 2011 









