C3N2H3I


















 





 





Iodine and Nitrogen


Nuclear Quadrupole Coupling Constants


in 2-Iodoimidazole



 








 








Iodine and nitrogen nuclear quadrupole coiupling constants in 2-iodoimidazole were determined by Cooper et al. [1].


 









Calculation of the 127I and 14N nqcc's was made here on a molecular structures given by B3LYP/cc-pVTZ (cc-pVTZ-PP for I) optimization.  Calculated nqcc's are compared with the experimental values in Tables 1 - 3.  Structure parameters are given in Table 4, rotational constants in Table 5.












In Tables 1 - 3, 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.  (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 B1LYP/TZV(df,p) model for calculation of iodine efg's/nqcc's; and in Tables 2 and 3, of the B3PW91/6-311+G(df,pd) model for nitrogen.






















   







Table 1.  Iodine nqcc's in 2-Iodoimidazole (MHz).  Calculation was made on B3LYP/cc-pVTZ optimized molecular structure.

   










 Calc

   Expt [1]
   







127I Xaa -
2031.1
-
2026.5535(80)



Xbb - cc

    46.0

    34.3916(84) *



Xbb
1038.5

1030.4726(58) **



Xcc
  992.5

  996.0809(58) **



|Xab|
    93.0

    93.55(15)











RMS
  5.7 (0.42 %)





RSD
15.2 (1.23 %)




 







Xxx
1041.3

1033.333(11)



Xyy
  992.5
  996.0809(58)


Xzz -
2033.9
-
2029.413(12)



ETA
-
0.0240





z,a
1.73





a,CI
1.81





z,CI
0.08













 








* This is given in Ref [1] as 4.3916(84), which does not reproduce the quadrupole axis system values also given in Ref [1], 34.3916(84) does.


** Calculated here from experimental Xaa and Xbb - cc

 









 









   







Table 2.  Nitrogen (pyrrolic) nqcc's in 2-Iodoimidazole (MHz).  Calculation was made on B3LYP/cc-pVTZ optimized molecular structure.

   










Calc

Expt [1]
   







14N(1) Xaa
1.336

1.3270(73)



Xbb - cc

4.231

4.1848(60)



Xbb
1.448

1.4289(47)



Xcc -
2.784
-
2.7559(47)


|Xab|
0.111

0.39(26)











RMS
0.020 (1.1 %)





RSD
0.030 (1.3 %)




 







Xxx
1.268

0.98(26)



Xyy
1.516

1.77(26)



Xzz -
2.784
-
2.7561(47)



ETA

0.0892





z,c
  0

  0











 









* Calculated here from experimental Xaa and Xbb - cc





















   







Table 3.  Nitrogen (pyridinic) nqcc's in 2-Iodoimidazole (MHz).  Calculation was made on B3LYP/cc-pVTZ optimized molecular structure.

   










Calc

Expt [1]
   







14N(3) Xaa
1.585

1.5506(73)



Xbb - cc
-
5.688
-
5.5700(60)



Xbb -
3.637
-
3.5603(47) *



Xcc
2.051

2.0097(47) *



|Xab|
1.642

1.89(24)











RMS
0.054 (2.3 %)





RSD
0.030 (1.3 %)



 







Xxx
2.059

2.17(14)



Xyy
2.051
2.0097(47)



Xzz -
4.110
-
4.18(14)



ETA
-
0.00183





z,a
73.91





a,bi**
71.58





z,bi
  2.33













 









* Calculated here from experimental Xaa and Xbb - cc

** "bi" is bisector of CNC angle.


 









 


Table 4.  2-Iodoimidazole: B3LYP/cc-pVTZ optimized structure parameters ( and degrees).
 





 

 N
 C,1,R1
 N,2,R2,1,A1
 C,3,R3,2,A2,1,D1,0
 C,4,R4,3,A3,2,D2,0
 H,1,R5,2,A4,3,D3,0
 H,4,R6,3,A5,2,D4,0
 H,5,R7,4,A6,3,D5,0
 I,2,R8,1,A7,5,D6,0







 R1=1.36210834
 R2=1.30166124
 R3=1.37793038
 R4=1.36574553
 R5=1.00478419
 R6=1.07623225
 R7=1.07484595
 R8=2.09167151
 A1=112.29714668
 A2=105.15848295
 A3=110.59659878
 A4=126.14450536
 A5=121.17487458
 A6=132.59784098
 A7=121.72754155
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=180.
 D6=180.




 








 








 


Table 5.  2-Iodoimidazole: Rotational Constants (MHz), ropt = B3LYP/cc-pVTZ
 




 ropt     Expt [1]





A
9453.
9357.00567(56)

B
1003.
1017.73058(21)

C
  907.
  917.75860(22)


 








 








[1]  G.A.Cooper, C.J.Anderson, C.Medcraft, N.Walker, J.Mol.Spectros. 354,15(2018).


 









G.A.Cooper, C.J.Anderson, C.Medcraft, A.Legon, N.Walker, Abstract FB11, 72nd ISMS, Champaign-Urbana, Illinois, 2017.


 








 








4-Iodopyrazole Iodobenzene 3-Iodothiophene
Imidazole


4-Iodoimidazole








 









 









Table of Contents




Molecules/Iodine








Molecules/Nitrogen




 








 













2Iimidazole.html






Last Modified 16 Sept 2018