C3N2H3I


















 





 





Iodine and Nitrogen

Nuclear Quadrupole Coupling Constants


in 4-Iodoimidazole


 








 








Iodine and nitrogen nuclear quadrupole coiupling constants in 4-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.  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 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 4-Iodoimidazole (MHz).  Calculation was made on B3LYP/cc-pVTZ optimized molecular structure.
   









 Calc
   Expt [1]
   






127I Xaa -
 1979.5
 -
 1980.759(10)


Xbb - cc
    49.6
    37.339(14)


Xbb
1014.5
1009.049(9) *


Xcc
  965.0
  971.710(9) *


|Xab|
    35.2
    37.79(14)










RMS
  5.1 (0.38 %)




RSD
15.2 (1.23 %)



 







Xxx
1014.9
1009.5263(95)


Xyy
  965.0
  971.7099(88)


Xzz -
 1979.9
 -
 1981.236(11)


ETA
 -
 0.0252




Øz,a
0.67




Øa,CI
0.47




Øz,CI
0.20












 








* Calculated here from experimental Xaa and Xbb - cc

 








 








   






Table 2.  Nitrogen (pyrrolic) nqcc's in 4-Iodoimidazole (MHz).  Calculation was made on B3LYP/cc-pVTZ optimized molecular structure.
   









Calc
Expt [1]
   






14N(1) Xaa
1.378
1.371(13)


Xbb - cc
3.608
3.674(11)


Xbb
1.115
1.151(8) *


Xcc -
 2.493
 -
 2.522(8) *


|Xab|
0.063
    -----










RMS
0.027 (1.6 %)




RSD
0.030 (1.3 %)



 







Xxx
1.101




Xyy
1.392




Xzz -
 2.493 -
 2.5223(86)


ETA
0.117




Øz,c
  0
  0










 








* Calculated here from experimental Xaa and Xbb - cc





















   






Table 3.  Nitrogen (pyridinic) nqcc's in 4-Iodoimidazole (MHz).  Calculation was made on B3LYP/cc-pVTZ optimized molecular structure.
   









Calc
Expt [1]
   






14N(3) Xaa
1.209
1.159(13)


Xbb - cc
 -
 5.296
 -
 5.169(11)


Xbb -
 3.253
 -
 3.164(8) *


Xcc
2.044
2.005(8) *


|Xab|
2.111
1.71(37)










RMS
0.063 (3.0 %)




RSD
0.030 (1.3 %)



 







Xxx
2.044
1.75(23)


Xyy
2.050
2.0051(86)


Xzz -
 4.093
 -
 3.76(23)


ETA
0.00148




Øz,a
68.29




Øa,bi**
69.99




Øz,bi
  1.70












 








* Calculated here from experimental Xaa and Xbb - cc

** "bi" is bisector of CNC angle.

 








 


Table 4.  4-Iodoimidazole: B3LYP/cc-pVTZ optimized structure parameters (Å 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
 I,4,R6,3,A5,2,D4,0
 H,5,R7,4,A6,3,D5,0
 H,2,R8,1,A7,5,D6,0






 R1=1.36026216
 R2=1.31260285
 R3=1.36320614
 R4=1.36845676
 R5=1.00537868
 R6=2.09385731
 R7=1.07357624
 R8=1.07699988
 A1=111.58535672
 A2=105.1442642
 A3=111.39304161
 A4=126.50125901
 A5=122.09921122
 A6=132.43584095
 A7=122.72942889
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=180.
 D6=180.



 








 








 


Table 5.  4-Iodoimidazole: Rotational Constants (MHz), ropt = B3LYP/cc-pVTZ
 




 ropt     Expt [1]





A
 9529.
 9431.8375(10)

B
   975.
   988.45251(12)

C
   885.
   894.54595(11)


 








 








[1]  G.A.Cooper, C.J.Anderson, C.Medcraft, N.Walker, J.Mol.Spectrosc. xxx,xxx(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

2-Iodoimidazole







 








 








Table of Contents




Molecules/Iodine







Molecules/Nitrogen




 








 













4Iimidazole.html






Last Modified 15 Sept 2018