p-CH3-C6H4-Br




 






















 








Bromine

Nuclear Quadrupole Coupling Constants


in p-Bromotoluene


 








 








 

 





Bromine nqcc's were calculated here on a molecular structure determined by B3P86/6-31G(3d,3p) and by PBE1PBE/6-31G(3d,3p) optimization, each assuming a plane of symmetry perpendicular to the plane of the ring.  These are compared with the experimental nqcc's [1] 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.  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.  RSD is the calibration residual standard deviation for the B1LYP/TZV(3df,3p) model for calculation of the efg's/nqcc's.

 








 








   







Table 1.  Bromine nqcc's in p-Bromotoluene (MHz).  Calculation was made on the (1)  B3P86/6-31G(3d,3p) and (2) PBE1PBE/6-31G(3d,3p) ropt structures.
   










Calc (1)
Calc (2)
Expt. [1]
   







79Br Xaa
558.27
557.03
555.618(8)


Xbb -
 292.32 -
 291.95
 -
 290.964(17) *


Xcc -
 265.95 -
 265.08
 -
 264.654(17) *


|Xac|
    0.98
    0.95


 








RMS
1.88 (0.51 %)
1.02 (0.28 %)



RSD
1.58 (0.39 %)
1.58 (0.39 %)


 







  Xxx -
 292.32 -
 291.95 -
 290.964(17)


Xyy -
 265.95 -
 265.08 -
 264.654(17)


Xzz
558.27
557.03
555.618(8)


ETA -
 0.0472 -
 0.0482



Øz,a
0.068
0.066



Øa,CBr
0.058
0.056



Øz,CBr
0.010
0.010


 







81Br Xaa
466.42
465.38
464.186(10)


Xbb -
 244.23 -
 243.92
 -
 243.120(5) **


Xcc -
 222.19 -
 221.46
 -
 221.066(5) **


|Xac|
    0.81
    0.79



 







RMS
1.58 (0.51 %)
0.86 (0.28 %)



RSD
1.38 (0.40 %)
1.38 (0.40 %)


 








 








* Calculated here from experimental Xaa and Xbb - Xcc = -26.311(34) MHz.

** Calculated here from experimental Xaa and Xbb - Xcc = -22.055(36) MHz.

 








 








 

Table 2.  p-Bromotoluene.  Molecular structure parameters, ropt(1) = B3P86/6-31G(3d,3p) and ropt(2) = PBE1PBE/6-31G(3d,3p) (Å and degrees).




 C
 C,1,B1
 C,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 C,4,B4,3,A3,2,D2,0
 C,1,B5,2,A4,3,D3,0
 H,1,B6,6,A5,5,D4,0
 H,2,B7,1,A6,6,D5,0
 H,4,B8,3,A7,2,D6,0
 H,5,B9,4,A8,3,D7,0
 C,6,B10,1,A9,2,D8,0
 H,11,B11,6,A10,1,D9,0
 H,11,B12,6,A11,1,D10,0
 H,11,B13,6,A12,1,D11,0
 Br,3,B14,2,A13,1,D12,0
 
ropt(1) ropt(2)
 B1         1.38858522
 B2         1.38744904
 B3         1.38744904
 B4         1.38858522
 B5         1.39470681
 B6         1.0859857
 B7         1.08273891
 B8         1.08273891
 B9         1.0859857
 B10       1.50172016
 B11       1.09249908
 B12       1.09536809
 B13       1.09249908
 B14       1.87945233
 A1         119.3957095
 A2         120.44309384
 A3         119.3957095
 A4         121.4249173
 A5         119.47291659
 A6         120.51424884
 A7         120.08978086
 A8         119.10194949
 A9         121.03754246
 A10       111.40822377
 A11       111.05376929
 A12       111.40822377
 A13       119.77812399
 D1             0.12609091
 D2            -0.12609091
 D3             0.04514582
 D4         179.62015032
 D5         179.859535
 D6         179.68910014
 D7         179.78460873
 D8         178.66842123
 D9         150.99307971
 D10        -89.42113663
 D11         30.16464703
 D12       179.83031685
 B1         1.38840921
B2         1.38752770
B3         1.38752770
B4         1.38840921
B5         1.39458709
B6         1.08682691
B7         1.08356560
B8         1.08356560
B9         1.08682691
B10       1.50145815
B11       1.09316102
B12       1.09601585
B13       1.09316102
B14       1.87579047
A1         119.41874464
A2         120.40382541
A3         119.41874464
A4         121.42007161
A5         119.11940560
A6         120.52625454
A7         120.05474644
A8         119.11940560
A9         121.03613820
A10       111.40545310
A11       111.02404240
A12       111.40545310
A13       119.79775496
D1             0.12643805
D2            -0.12643805
D3            -0.04254778
D4        -179.78491209
D5         179.85917068
D6         179.69106425
D7         179.78491209
D8        -178.67852661
D9          -30.15110952
D10          89.42398802
D11       -151.00091445
D12        179.82926882



 







 
 



Table 3.  p-Bromotoluene.  Rotational constsnts, 79Br species.  ropt(1) = B3P86/6-31G(3d,3p) and ropt(2) = PBE1PBE/6-31G(3d,3p).
   




ropt(1) ropt(2) Expt [1]

 



A
 5572.5
 5572.6
 5706.65(32)

B
   641.1
   642.0
   636.97364(24)

C
   577.0
   577.8
   573.02879(27)

 





 








 








[1] V.A.Shubert, D.Schmitz, and M.Schnell, Mol.Phys. 111,2189(2013).

 








 








p-Chlorotoluene Bromobenzene

p-Iodotoluene

 








 








Table of Contents





Molecules/Bromine




 








 













4BrToluene.html






Last Modified 5 Aug 2013