CF3-C(=O)-CF2Br
























 






Bromine


Nuclear Quadrupole Coupling Constants

in Bromoperfluoroacetone

 








 








The microwave spectrum of bromoperfluoroacetone was assigned by Grubbs, et al. [1,2].

 








Calculation of the nqcc's was made here on a molecular structure (ropt) derived by MP2/6-311+G(3df,3pd) optimization, and on this same structure but with empirically corrected bond lengths (~ re) as described here.  Calculated nqcc's are compared with the experimental values in Tables 1 and 2.  Structure parameters are given in Z-matrix format in Table 3, rotational constants in Table 4.

 








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.  Øz,CBr (degrees) is the angle between the z-principal axis and the CBr bond axis.

 








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(3df,3p) model for calculation of the bromine efg's/nqcc's.

 







 
   







Table 1.  79Br nqcc's in CF3-C(=O)-CF2Br (MHz).  Calculation was made on the (1) ropt and (2) ~ re structures.
   









Calc. (1)
Calc. (2)
Expt. [2]
   







Xaa
121.14
123.13
105.98(2)

Xbb
156.50
155.61
164.28(2)

Xcc - 277.64 - 278.74 -
 270.26(2)

Xab
433.27
434.12
427.5(4)

Xac
  96.27
  94.88
 -
 109.(1)

Xbc
123.34
121.37 -
 125.2(1)

 







RMS
10.7 (5.9 %)
 12.1 (6.7 %)


RSD
1.58 (0.39 %)
1.58 (0.39 %)



 







Xxx - 283.47 - 283.78 -
 290.5(7)

Xyy - 316.60 - 316.73 -
 304.9(4)

Xzz
600.07
600.51
595.4(5)

ETA
0.0552
0.0549
0.0241(1)

Øz,CBr
2.11
2.11



 








 








 








   







Table 2.   81Br nqcc's in CF3-C(=O)-CF2Br (MHz).  Calculation was made on the (1) ropt and (2) ~ re structures.
   









Calc. (1)
Calc. (2)
Expt. [2]
   







Xaa
104.96
106.63
  92.33(3)

Xbb
127.71
126.93
134.17(2)

Xcc - 232.67 - 233.56 -
 226.51(2)

Xab
362.43
363.11
359.5(3)

Xac
  79.63
  78.49
  82.(1)

Xbc
101.32
  99.71
102.8(1)

 







RMS
8.93 (5.9 %)
 10.1 (6.7 %)


RSD
1.38 (0.40 %)
1.38 (0.40 %)



 








 








 













Table 3.  CF3-C(=O)-CF2Br   MP2/6-311+G(3df,3pd) Structure Parameters (Å and degrees).  Approximate equilibrium (~ re) bond lengths are given in parentheses.
 








 C
 O,1,B1
 C,1,B2,2,A1
 C,1,B3,2,A2,3,D1,0
 Br,4,B4,1,A3,2,D2,0
 F,3,B5,1,A4,2,D3,0
 F,3,B6,1,A5,2,D4,0
 F,3,B7,1,A6,2,D5,0
 F,4,B8,1,A7,2,D6,0
 F,4,B9,1,A8,2,D7,0



 B1=1.19914455      (1.1948)
 B2=1.54791749      (1.5445)
 B3=1.54016334      (1.5371)
 B4=1.92956664      (1.9331)
 B5=1.33387814      (1.3327)
 B6=1.32049164      (1.3196)
 B7=1.33094901      (1.3298)
 B8=1.33788365      (1.3366)
 B9=1.32876433      (1.3277)
 A1=121.67858761
 A2=121.63951406
 A3=108.07732788
 A4=108.81765096
 A5=110.17810187
 A6=111.37161327
 A7=110.77281976
 A8=109.60079007
 D1=178.75021533
 D2=90.55781372
 D3=101.02064043
 D4=-18.25474581
 D5=-139.28218808
 D6=-148.84959903
 D7=-29.08185185






 













Table 4.  CF3-C(=O)-CF2Br  Rotational Constants (MHz).  79Br Species.







  ropt   ~ re   Expt. [2]






A 1522.0
 1524.5
 1516.9240(6)

B   658.3
   659.6
   655.5786(2)

C   613.8
   614.7
   609.3570(2)


 








 








[1] N.Force, D.J.Gillcrist, C.C.Hurley, F.E.Marshall, N.A.Payton, T.D.Persinger, N.E.Shreve, and G.S.Grubbs II, Abstract WJ08, 69th International Symposium on Molecular Spectroscopy, Champaign-Urbana, 2014.

[2] F.E.Marshall, D.J.Gillcrist, T.D.Persinger, S.Jaeger, C.Hurley, N.E.Shreve, N.Moon, G.S.Grubbs II, Abstract WE05, 71st International Symposium on Molecular Spectroscopy, Champaign-Urbana, 2016; J.Mol.Spectrosc. 328,59(2016).

 








 








CF3-C(=O)-CF2Cl




 








 








Table of Contents




Molecules/Bromine




 








 













CF3COCF2Br.html






Last Modified 26 Sept 2016