C3H5-CH2Br













 








Bromine

Nuclear Quadrupole Coupling Constants

in (Bromomethyl)cyclopropane

 








 








Calculation of the bromine nqcc tensors in (bromomethyl)cyclopropane was made on MP2/6-311+G(d,p) and MP2/6-311+G(2d,2p) optimized structures of gauche and cis conformers shown below:

 








gauche, C1

cis, Cs































 








At MP2/6-311+G(d,p) and MP2/6-311+G(2d,2p) levels of theory respectively, Egauche < Ecis by 7.2/6.4 kJ/mol.











Calculated nqcc tensors are shown in Tables 1 and 2, structure parameters in Table 3, rotational constants and dipole moments in Table 4, quartic centrifugal distortion constants in Table 5.

 








In Tables 1 and 2, 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.

RSD is the calibration residual standard deviation of the B1LYP/TZV(3df,3p) model for calculation of the efg's/nqcc's.

 








 








 








Table 1.  Bromine nqcc's in gauche (bromomethyl)cyclopropane (MHz).  Calculation was made on (1) MP2/6-311+G(d,p) and (2) MP2/6-311+G(2d,2p) optimized structures.
 










Calc (1)
Calc (2)
Expt
 








Xaa (79Br)
335.63
340.77



Xbb
- 76.02
- 81.51



Xcc -
 259.61
 -
 259.27



Xab
 -
 349.14
 -
 344.26



Xac
- 85.05
- 82.96



Xbc
  50.58
  48.67



 







RSD
1.58 (0.39 %)
1.58 (0.39 %)












Xxx -
 276.15
 -
 275.08



Xyy -
 271.08
 -
 269.90



Xzz
547.23
544.98



ETA -
 0.00926
 -
 0.00952



Øz,CBr
0.49
0.36












Xaa (81Br)
280.76
289.21



Xbb
- 63.85
- 64.45



Xcc -
 216.91
 -
 224.76



Xab
 -
 291.50
307.01



Xac
- 71.05
- 70.84



Xbc
  42.20
- 47.13












RSD
1.38 (0.40 %)
1.38 (0.40 %)













 








 








 








Table 2.  Bromine nqcc's in cis (bromomethyl)cyclopropane (MHz).  Calculation was made on (1) MP2/6-311+G(d,p) and (2) MP2/6-311+G(2d,2p) optimized structures.
 










Calc (1)
Calc (2)
Expt
 








Xaa (79Br)
158.28
162.20



Xbb
124.37
119.99



Xcc -
 282.65
 -
 282.19



Xab
 -
 410.55
 -
 409.67



 







RSD
1.58 (0.39 %)
1.58 (0.39 %)












Xxx -
 269.57 -
 269.12



Xyy -
 282.65 -
 282.19



Xzz
552.23
551.31



ETA
0.0236
0.0237



Øz,a
43.82
43.53



Øa,CBr
44.62
44.45



Øz,CBr
  0.81
  0.92












Xaa (81Br)
133.18
136.45



Xbb
102.96
  99.30



Xcc -
 236.15
 -
 235.76



Xab
 -
 342.96
 -
 342.22












RSD
1.38 (0.40 %)
1.38 (0.40 %)













 








 


Table 3.  (Bromomethyl)cyclopropane heavy atom structure parameters (Å and degrees), ropt(1) = MP2/6-311+G(d,p) and ropt(2) = MP2/6-311+G(2d,2p) .  Complete molecular structure parameters are given here in Z-matrix format.
 


gauche, C1
ropt(1) ropt(2)
 



C(1)C(2) 1.50571.5026
C(1)C(3) 1.51491.5127
C(2)C(3) 1.51231.5102
C(1)C(9) 1.49631.4890
C(9)Br 1.95821.9615
C(1)C(2)C(3)   60.26
  60.27
C(1)C(3)C(2)   59.66
  59.61
C(2)C(1)C(3)   60.09
  60.11
C(2)C(1)C(9) 119.27118.77
C(1)C(9)Br 111.38111.72
C(2)C(1)C(9)Br - 82.29
- 82.56
 


 


cis, Cs
ropt(1) ropt(2)
 


C(1)C(2) 1.50621.5033
C(1)C(3) 1.50621.5033
C(2)C(3) 1.51601.5137
C(1)C(9) 1.50911.5027
C(9)Br 1.94921.9524
C(1)C(2)C(3)   59.78  59.77
C(1)C(3)C(2)   59.78  59.77
C(2)C(1)C(3)   60.43
  60.46
C(2)C(1)C(9) 123.47123.06
C(1)C(9)Br 114.08114.16
C(2)C(1)C(9)Br   37.11
  36.92


 








 














Table 4. (Bromomethyl)cyclopropane, 79Br species.  Rotational constants (MHz) and Dipole Moments * (D).  ropt(1) = MP2/6-311+G(d,p) and ropt(2) = MP2/6-311+G(2d,2p)









 ropt(1)  ropt(2)   Expt [1]







gauche
 A 11362.2
 11456.4
 11469.285


B   1369.3
   1370.7
   1374.777


C   1290.7
   1293.0
   1295.394

  |µa|
   2.12
   2.16


|µb|   0.74
   0.74


|µc|   0.09
   0.09







    cis
 A
   7595.7
   7620.7
   8759.918


B
   1759.8
   1771.3
   1597.413


C
   1629.3
   1639.1
   1522.141


|µa|   1.55
   1.57


|µb|   1.21
   1.22


|µc|   0 (symm)
   0 (symm)







* B1LYP/TZV(3df,3p) calculation of dipole moments on ropt strcutures.


 








 

















Table 5.  (Bromomethyl)cyclopropane, 79Br species.  Quartic Centrifugal Distortion Constants (kHz).  Calc = B3LYP/cc-pVTZ











gauche
  Expt
  cis
  Expt









Delta_J
0.300


0.512

Delta_JK -
 2.90

-
 0.432

Delta_K
34.6


5.14

delta_J
0.0310


0.0585

delta_K
1.28

-
 1.66

D_J
0.297


0.520

D_JK -
 2.88

-
 0.483

D_K
34.6


5.18

d_1
 -
 0.0310

-
 0.0585

d_2
 -
 0.00118


0.00419




 








 








[1] M.A.Mohammdi and W.V.F.Brooks, J.Mol.Spectrosc. 77,42(1979).

 








 








(Bromomethyl)oxirane
(Chloromethyl)cyclopropane


(Chloromethyl)oxirane




 








 








Table of Contents




Molecules/Bromine




 








 













BrMeCP.html






Last Modified 6 Jan 2014