2-CN-C4H3S






 














 






 








Nitrogen


Nuclear Quadrupole Coupling Constants


in 2-Cyanothiophene


 








 








Calculation of the nitrogen nqcc tensor in 2-cyanothiophene was made here on molecular structures given by B3PW91/6-31G(2d,2pd) and B3P86/6-31G(3d,3p) optimization.  Calculated and (limited)  experimental nqcc's are compared in Table 1.  Structure parameters are given in Table 2, rotational constants in Table 3.

 








In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor, subscripts 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 plane of the molecule.  (degrees) is the angle between its subscripted parameters. ETA = (Xxx - Xyy)/Xzz.  RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the efg's/nqcc's.

 








 








   








Table 1.  14N nqcc's in 2-Cyanothiophene (MHz).

 







Calculation was made on


the [a] B3PW91/6-31G(2d,2pd) opt structure, and


the [b] B3P86/6-31G(3d,3p) opt structure.
   










Calc. [a]

Calc. [b]
Expt. [1]

   








Xaa -
4.139
-
4.150
-
4.04(16)


Xbb
2.548

2.560




Xcc
1.591

1.591




|Xab|
0.548

0.537




 







RSD
0.030 (1.3 %)
0.030 (1.3 %)


 







Xxx
2.593

2.602




Xyy
1.591
1.591



Xzz -
4.184
-
4.193




ETA -
0.239
-
0.241




z,a
4.65

4.55




a,CN
4.82

4.79




z,CN
0.17

0.24




 








 








 



Table 2.  2-Cyanothiophene and Thiophene.  Structure parameters ( and degrees).
 





B3P86 B3PW91 B3PW91


X = CN X = CN X = H






S(1)C(2) 1.7254 1.7334 1.7197

C(2)C(3) 1.3772 1.3760 1.3660

C(3)C(4) 1.4118 1.4142 1.4229

C(4)C(5) 1.3699 1.3693 1.3660

C(5)S(1) 1.7039 1.7122 1.7197

C(2)X(2) 1.4112 1.4134 1.0787

X(2)N
1.1594
1.1607


C(3)H(3) 1.0821 1.0806 1.0816

C(4)H(4) 1.0822 1.0808 1.0816

C(5)H(5) 1.0805 1.0792 1.0787

C(5)S(1)C(2)   91.56   91.43   91.95

S(1)C(2)C(3) 111.35 111.26
111.42

C(2)C(3)C(4) 112.34 112.54
112.60

C(3)C(4)C(5) 112.42 112.55
112.60

C(4)C(5)S(1) 112.32 112.23
111.42

S(1)C(2)X(2) 121.20 120.97
119.93

C(2)X(2)N 179.98
179.87


S(1)C(5)H(5) 119.59 119.46
119.93

C(3)C(4)H(4) 124.13 123.92
124.04

C(4)C(3)H(3) 125.03 124.80
124.04


 























Table 3.  2-Cyanothiophene.  Rotational Constants (MHz).
   



[a] B3PW91/6-31G(2d,2pd) opt structure.

[b] B3P86/6-31G(3d,3p) opt structure.
 





Calc [a] Calc [b] Expt. [1]






A
5400.6
5421.5
5402.469(14)

B
1815.6
1822.8
1816.231(3)

C
1358.8
1364.2
1358.588(3)



  








[1] J.Wiese, L.Engelbrecht, and H.Dreizler, Z.Naturforsch. 32a,152(1977).


 









T.K.Avirah, T.B.Malloy Jr., and R.L.Cook, J.Mol.Struct. 29,47(1975).


 








 








Thiophene 2-Cyanofuran 2-Bromothiophene

3-Chlorothiophene 3-Bromothiophene 2-Chlorothiophene

3-Cyanothiophene







 








Table of Contents




Molecules/Nitrogen




 








 













2CNThiophene.html






Last Modified 11 June 2014