C2H2N2S




 

 





 


Nitrogen


Nuclear Quadrupole Coupling Constants


in 1,2,3-Thiadiazole


 







 

 


 




Calculation of the nitrogen nqcc's in 1,2,3-Thiadiazole was made on the substitution molecular structure of Stiefvater [1,2].  These are given in Tables 1 and 2.  Structure paameters are given in Table 3.
 
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.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the molecular plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of nitrogen nqcc's.
 
 
   







Table 1.  N(2) nqcc's in 1,2,3-Thiadiazole (MHz).  Calculation was made on the rs structure of Stiefvater [1,2].
   










Calc.
Expt.
   






14N(2) Xaa 2.432
Xbb - 3.512
Xcc 1.080
|Xab| 2.229
 
RSD 0.030 (1.3 %)
 
Xxx 3.175
Xyy 1.080
  Xzz - 4.255
  ETA - 0.492
Øz,a 71.56
Øa,bi 80.36
Øz,bi *   8.80
 
 
* The z-axis makes an angle of 8.80o with the external bisector ('bi') of the SNN angle and tilts toward S(1).
 
 
   







Table 2.  N(3) nqcc's in 1,2,3-Thiadiazole (MHz).  Calculation was made on the rs structure of Stiefvater [1,2].
   










Calc.
Expt.
   






14N(3) Xaa - 1.705
Xbb - 0.986
Xcc 2.690
|Xab| 3.555
 
RSD 0.030 (1.3 %)
 
Xxx 2.228
Xyy 2.690
  Xzz - 4.918
  ETA 0.094
Øz,a 42.11
Øa,bi 32.22
Øz,bi *   9.89
 
 
* The z-axis makes an angle of 9.89o with the external bisector ('bi') of the NNC angle and tilts toward N(2).
 
 
 
Table 3.  1,2,3-Thiadiazole.  Molecular structure parameters, rs [1,2] (Å and degrees).
 
S(1)N(2) 1.6917(6)
N(2)N(3) 1.2897(8)

N(3)C(4) 1.3662(20)
C(4)C(5) 1.3686(20)
C(5)S(1) 1.6888(8)
C(4)H(4) 1.0779(10)
C(5)H(5) 1.0805(18)
C(5)S(1)N(2)   92.91(10)
S(1)N(2)N(3) 111.21(10)
N(2)N(3)C(4) 113.95(10)
N(3)C(4)C(5) 114.15(10)
C(4)C(5)S(1) 107.79(10)
N(3)C(4)H(4) 119.23(10)
C(5)C(4)H(4) 126.62(8)
C(4)C(5)H(5) 129.36(20)
S(1)C(5)H(5) 122.85(30)


 
 

[1] O.L.Stiefvater, Chem.Phys. 13,73(1976).
[2] Landolt-Börnstein, Numerical Data and Functional Relationships in Science and Technology, New Series, ed. O.Madelung, Group II, Volume 15, Structure Data of Free Polyatomic Molecules, eds: K.-H.Hellwege and A.M.Hellwege, Springer-Verlag, Berlin.

 








 







Thiazole 1,3,4-Oxadiazole 1,2,5-Oxadiazole
1,2,4-Thiadiazole 1,2,5-Thiadiazole 1,3,4-Thiadiazole
 

 








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Molecules/Nitrogen



 

 













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Last Modified 30 Jan 2005