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CH2Br-C(=O)OH
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Bromine |
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Nuclear
Quadrupole Coupling Constants |
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in Bromoacetic Acid |
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Calculation of the bromine nqcc
tensors was made here on structures given by MP2/aug-cc-pVTZ(G03)
optimization (ropt), and on this optimized structure but with corrected
CBr, C-C, and C=O bond lengths (~ re, see here). These nqcc's are compared with the experimental values [1] in Table 1. Structure parameters are
given in Table 2, rotational constants in Table 3. |
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In Table 1, subscripts a,b,c refer to the principal axes of the inertia
tensor; 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 molecular symmetry plane. Ø (degrees) is the angle between its subscripted
parameters. ETA = (Xxx - Xyy)/Xzz. |
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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 for the B1LYP/TZV(3df,3p) model
for calculation of the nqcc's, which may be taken as an estimate ofthe uncertainty in the calculated nqcc's. |
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Table 1. Bromine nqcc's in CH2Br-C(=O)OH (MHz). Calculation was made on the (1) ropt and (2) ~ re structures. |
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Calc (1)
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Calc (2) |
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Expt. [1] |
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Xaa(79Br) |
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421.06 |
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424.26 |
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421(4) |
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Xbb |
- |
120.22 |
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122.27 |
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121(2) |
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Xcc |
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300.84 |
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301.99 |
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300(2) |
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|Xab| |
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370.47 |
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370.70 |
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365(2) |
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RMS |
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0.7 (0.24 %) |
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2.3 (0.83 %) |
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RSD |
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1.58 (0.39 %) |
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1.58 (0.39 %) |
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Xxx |
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308.38 |
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309.54 |
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304(2) |
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Xyy |
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300.84 |
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301.99 |
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300(2) |
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Xzz |
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609.22 |
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611.53 |
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604(3) |
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ETA |
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0.0124 |
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0.0124 |
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Øz,a |
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26.92 |
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26.80 |
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26.7(2) |
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Øa,CCl |
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27.56 |
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27.42 |
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Øz,CCl |
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0.63 |
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0.62 |
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Xaa(81Br) |
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351.86 |
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354.53 |
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354(4) |
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Xbb |
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100.52 |
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102.23 |
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102(2) |
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Xcc |
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251.34 |
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252.30 |
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251(2) |
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|Xab| |
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309.46 |
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309.65 |
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306(4) |
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RMS |
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1.5 (0.64 %) |
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0.8 (0.35 %) |
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RSD |
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1.38 (0.40 %) |
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1.38 (0.40 %) |
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| Table 2. Bromoacetic Acid. Molecular structure parameters, ropt and ~ re (Å and degrees). |
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| Point Group Cs |
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ropt |
~ re |
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BrC |
1.9085 |
1.9168 |
| CH |
1.0864 |
1.0864 |
| C-C |
1.5094 |
1.5079 |
| C=O |
1.2037 |
1.1964 |
| CO |
1.3561 |
1.3561 |
| OH |
0.9703 |
0.9703 |
| BrCC |
112.48 |
112.48 |
| CCH |
109.22 |
109.22 |
| HCC=O |
±120.59 |
±120.59 |
| CC=O |
127.62 |
127.62 |
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OC=O |
123.96 |
123.96 |
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COH |
112.48 |
112.48 |
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| Table 3. Bromoacetic Acid. Rotational constants (MHz). 79Br species. |
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ropt |
~ re |
Expt. [1] |
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A |
10436.1 |
10505.5 |
10460.377(19) |
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B |
1530.3 |
1524.5 |
1514.793(5) |
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C |
1345.8 |
1342.4 |
1335.161(4) |
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[1] B.P. van Eijck, H.A.Dijkerman, and J.Smits, J.Mol.Spectrosc. 73,305(1978). |
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CH2Br-C(=O)F |
CH2Br-CH3 |
CH2Br-C(=O)Cl |
CH2Cl-C(=O)OH |
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Table of Contents |
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Molecules/Bromine |
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CH2BrCOOH.html |
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Last
Modified 21 April 2008 |
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