2-Bromopyrimidine





 









Nitrogen and Bromine


Nuclear Quadrupole Coupling Constants


in 2-Bromopyrimidine


 











 




Chen, Paulse, and Davis [1] measured the bromine nqcc's in 2-bromopyrimidine and determined an effective molecular structure.
 
Calculation of both nitrogen and bromine nqcc's were made here on the B3P86/6-31G(3d,3p) optimized molecular structure.  The nitrogen results are shown in Table 1.  In Table 2, calculated bromine nqcc's are compared with the experimental values.  Structure parameters, effective and optimized, are compared in Table 3; rotational constants, in Table 4.  In Table 5, atomic coordinates are given for the optimized structure.

 







 








 









 







Table 1. Nitrogen nqcc's in 2-Bromopyrimidine (MHz).
 










Calc.
Expt. 
 







14N(1,3) Xaa - 0.049


Xbb -
2.911



Xcc 2.961


Xab ± 2.877


 








RSD 0.030 (1.3 %)
 








Xxx 1.733


Xyy 2.961


Xzz -
4.694



ETA
0.262



Øz,a
58.22



Øa,bi
58.22



Øz,bi*
  0.00

   







 








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

 








 








 







Table 2. Bromine nqcc's in 2-Bromopyrimidine (MHz).
 










Calc.
Expt. [1]
 







79Br Xaa 566.99 567.8(7)


Xbb -
334.93 -
329(5)


Xcc - 232.07 - 239(5)


ETA * - 0.181


 
 
RMS

5.3 (1.4 %)





RSD 1.58 (0.39 %)
 







81Br Xaa 473.71 475.6(6)


Xbb - 279.82 - 274(2)


Xcc -
193.88 -
201(2)







RMS
5.4 (1.7 %)



RSD
1.38 (0.40 %)

   






* ETA = (Xbb - Xcc)/Xaa = (Xxx - Xyy)/Xzz.
Table 3. Structure parameters ropt and ro (Å and degrees).
ropt  ro [1]
C(2)Br(2) 1.8778 1.889
C(2)N(3) 1.3227 1.3305
N(3)C(4) 1.3333 1.340
C(4)C(5) 1.3868 1.391
C(4)H(4) 1.0871 1.081
C(5)H(5) 1.0826 1.081
N(1)C(2)N(3) 128.28 128.51
C(2)N(3)C(4) 115.28
N(3)C(4)C(5) 122.52
C(4)C(5)C(6) 116.11 116.6
C(5)C(4)H(4) 121.37 121.5
 
Table 4.  Rotational Constants (MHz).  79Br species.
Calc. ropt Expt. [1]
A 6147.4 6078.760(66)
B 1072.3 1062.99006(61)
C   913.0   904.71668(45)
 
Table 5. Atomic coordinates, ropt   79Br species.  
(More figures are shown than are significant.)
  a (Å)   b (Å)
N(1,3) - 0.867367 ± 1.190200
C(2) - 0.290424 0.0
C(4,6) - 2.200591 ± 1.176793
C(5) - 2.934377 0.0
Br(2) 1.587355 0.0
H(4,6) - 2.688798 ± 2.148151
H(5) - 4.016938 0.0

 








[1] J.Chen, C.D.Paulse, and R.W.Davis, J.Mol.Spectrosc. 145,18 (1991).

 








 







Pyrimidine 2-Chloropyrimidine
2-Fluoropyrimidine 2-Cyanopyrimidine

 








 








Table of Contents




Molecules/Nitrogen




Molecules/Bromine




 








 













2BrPRM.html






Last Modified 27 Feb 2004