Thiazole



PDF

 






Nitrogen and Sulfur


Nuclear Quadrupole Coupling Constants


in Thiazole


 








 


















Calculation of nitrogen and sulfur nqcc's in thiazole was made on the substitution structure of Nygaard et al. [1], and on a molecular structure obtained by B3PW91/6-31G(2d,2pd) optimization [2].  These are compared in Tables 1 - 8 with the experimental nqcc's of Kretschmer and Dreizler [3].  Structure parameters are compared in Table 9.

 








In Tables 1 and 8, 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.

 








RMS is the root mean square difference between calculated and experimental nqcc's (percentage of average experimental nqcc).  RSD is the residual standard deviation of calibration of the model for calculation of the nqcc's.

 








 








   







Table 1. Nitrogen nqcc's in Thiazole (MHz).  Calculation was made on the rs structure of Nygaard et al. [1].
   










Calc.
Expt. [3]
   







14N Xaa - 2.706 - 2.7481(15)


Xbb
0.056
0.08505


Xcc
2.650
2.6630


|Xab|
2.581



 







RMS
0.030 (1.7 %)




RSD
0.030 (1.3 %)



 







Xxx
1.602
1.613 *


Xyy
2.650
2.6630


Xzz - 4.252 - 4.276


ETA
0.246
0.246


z,a
30.92
30.62


a,bi
31.53
31.53


z,bi**
  0.61
  0.91

 






   








* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.

** Angle between the z-axis and the bisector ( 'bi' ) of the CNC angle.

 








 








   







Table 2. Nitrogen nqcc's in Thiazole (MHz).  Calculation was made on the B3PW91/6-31G(2d,2pd) structure.
   










Calc.
Expt. [3]
   







14N Xaa - 2.745 - 2.7481(15)


Xbb
0.078
0.08505


Xcc
2.666
2.6630


|Xab|
2.558



 







RMS
0.005 (0.26 %)




RSD
0.030 (1.3 %)



 







Xxx
1.589
1.592 *


Xyy
2.666
2.6630


Xzz - 4.255 - 4.256


ETA
0.253
0.252


z,a
30.55
30.51


a,bi
31.36
31.36


z,bi**
  0.81
  0.85

 







 








* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.

** Angle between the z-axis and the bisector ( 'bi' ) of the CNC angle.

 








 








   







Table 3. Nitrogen nqcc's in Thiazole-33S (MHz).  Calculation was made on the rs structure of Nygaard et al. [1].
   










Calc.
Expt. [3]
   







14N Xaa - 2.699 - 2.7411(49)


Xbb
0.049
0.0767(69)


Xcc
2.650
2.6644


|Xab|
2.585



 







RMS
0.030 (1.6 %)




RSD
0.030 (1.3 %)



 







 








   







Table 4. Nitrogen nqcc's in Thiazole-33S (MHz).  Calculation was made on the B3PW91/6-31G(2d,2pd) structure.
   










Calc.
Expt. [3]
   







14N Xaa - 2.738 - 2.7411(49)


Xbb
0.071
0.0767(69)


Xcc
2.666
2.6644


|Xab|
2.562



 







RMS
0.004 (0.22 %)




RSD
0.030 (1.3 %)



 







 








 








   







Table 5. Nitrogen nqcc's in Thiazole-34S (MHz).  Calculation was made on the rs structure of Nygaard et al. [1].
   










Calc.
Expt. [3]
   







14N Xaa - 2.693 - 2.7359(23)


Xbb
0.043
0.0716


Xcc
2.650
2.6664


|Xab|
2.588



 







RMS
0.031 (1.7 %)




RSD
0.030 (1.3 %)



 







 








   







Table 6. Nitrogen nqcc's in Thiazole-34S (MHz).  Calculation was made on the B3PW91/6-31G(2d,2pd) structure.
   










Calc.
Expt. [3]
   







14N Xaa - 2.731 - 2.7359(23)


Xbb
0.065
0.0716


Xcc
2.666
2.6664


|Xab|
2.566



 







RMS
0.005 (0.27 %)




RSD
0.030 (1.3 %)



 







 








 








   








Table 7.  33S nqcc's in Thiazole (MHz).  Calculation was made on the rs structure of Nygaard et al. [1].











Calc. [a] B3LYP/6-311G(3df,3p) Model.


Calc. [b] B3LYP/TZV+(3df,3p) Model.
   










Calc. [a]

Calc. [b]
Expt. [3]
   








Xaa
  7.54
  7.62
  7.1708(61)

Xbb - 25.85 - 25.95 - 26.1749(69)

Xcc
18.30
18.32
19.0041(130)

|Xab|
  0.81
  0.88



 







RMS
0.49 (2.8 %) 0.49 (2.8 %)


RSD
0.39 (1.7 %) 0.35 (1.5 %)


 







Xxx
  7.56
  7.65
  7.19 *

Xyy
18.30
18.32
19.0041

Xzz - 25.86 - 25.97 - 26.20

ETA
0.415
0.411
0.451

x,a
1.38
1.49
1.46

a,bi
3.28
3.28
3.28

x,bi**
1.90
1.79
1.82

 


















* Calculated here from the experimental diagonal nqcc's and 0.85 MHz for |Xab|.

** Angle between the x-axis and the bisector ( 'bi' ) of the CSC angle.

 








 








   








Table 8.  33S nqcc's in Thiazole (MHz).  Calculation was made on the B3PW91/6-31G(2d,2pd) structure.











Calc. [a] B3LYP/6-311G(3df,3p) Model.


Calc. [b] B3LYP/TZV+(3df,3p) Model.
   










Calc. [a]

Calc. [b]
Expt. [3]
   








Xaa
  7.17
  7.25
  7.1708(61)

Xbb - 25.96 - 26.06 - 26.1749(69)

Xcc
18.79
18.81
19.0041(130)

|Xab|
  0.73
  0.80



 







RMS
0.17 (0.98 %) 0.14 (0.78 %)


RSD
0.39 (1.7 %) 0.35 (1.5 %)


 







Xxx
  7.19
  7.27
  7.19 *

Xyy
18.79
18.81
19.0041

Xzz - 25.98 - 26.08 - 26.19

ETA
0.447
0.442
0.451

x,a
1.27
1.38
1.32

a,bi
3.35
3.35
3.35

x,bi**
2.08
1.97
2.03

 








 








* Calculated here from the experimental diagonal nqcc's and 0.77 MHz for |Xab|.

** Angle between the x-axis and the bisector ( 'bi' ) of the CSC angle.

 








 



Table 9. Molecular structure parameters, B3PW91/6-31G(2d,2pd) ropt and rs [1] ( and degrees).
 






  rs [1]   ropt 







S(1)C(2) 1.7239(9) 1.7313


C(2)N(3) 1.3042(11) 1.2988


N(3)C(4) 1.3721(2) 1.3690


C(4)C(5) 1.3670(4) 1.3635


C(5)S(1) 1.7130(3) 1.7187


C(2)H(2) 1.0767(18) 1.0818


C(4)H(4) 1.0798(1) 1.0818


C(5)H(5) 1.0765(2) 1.0781


C(5)S(1)C(2)   89.33(3)   89.03


S(1)C(2)N(3) 115.18(1) 115.14


C(2)N(3)C(4) 110.12(2) 110.28


N(3)C(4)C(5) 115.81(2) 116.09


C(4)C(5)S(1) 109.57(1) 109.46


S(1)C(2)H(2) 121.26(5) 120.56


N(3)C(4)H(4) 119.35(1) 119.18


C(4)C(5)H(5) 129.03(3) 129.10


 








 








[1] L.Nygaard, E.Asmussen, J.H.Hg, R.C.Maheshwari, C.H.Nielsen, I.B.Petersen, J.Rastrup-Andersen, and G.O.Srensen, J.Mol.Struct. 8, 225(1971).

[2] W.C.Bailey, J.Mol.Spectrosc. 209,57(2001).

[3] U.Kretschmer and H.Dreizler, Z.Naturforsch. 48a,1219(1993).











J.Wiese and D.H.Sutter, Z.Naturforsch. 35a,712(1980): Xaa = -2.708(22), Xbb = 0.113(34), Xcc = 2.595(34) MHz.


 








 








2-Methylthiazole 1,2,4-Thiadiazole Pyrazole

4-Methylthiazole 1,2,5-Thiadiazole Oxazole

5-Methylthiazole 1,3,4-Thiadiazole Imidazole

 








 








Table of Contents




Molecules/Nitrogen




Molecules/Sulfur




 








 













Thiazole.html






Last Modified 27 Sept 2004