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3-F-C5H4N
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in 3-Fluoropyridine |
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Calculation of the nitrogen nqcc's
in 3-fluoropyridine was made here on a molecular structure given by
B3P86/6-31G(3d,3p) optimization. These are compared with the
experimental nqcc's [1] in Table 1. Structure parameters are
given in Table 2, atomic coordinates in Table 3, and rotational
constants in Table 4. |
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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 plane. Ø (degrees) is the angle between its
subscripted parameters. ETA = (Xxx - Xyy)/Xzz.
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RMS is the root mean square differene between calculated and
experimental nqcc's (percent of average experimental nqcc). RSD
is the calibration residual standard deviation of the model for
calculation of the nqcc's. |
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Table 1. Nitrogen nqcc's in 3-Fluoropyridine (MHz). Calculation
was made on the B3P86/6-31G(3d,3p) ropt structure. |
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Calc. |
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Expt. [1] |
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14N |
Xaa |
- |
0.038 |
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0.06(3) |
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Xbb |
- |
3.469 |
- |
3.52(8) |
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Xcc |
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3.507 |
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3.46(11) |
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|Xab| |
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2.753 |
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RMS |
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0.07 (3.0 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.490 |
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1.55 * |
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Xyy |
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3.507 |
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3.46 |
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Xzz |
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4.997 |
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5.01 |
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ETA |
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0.404 |
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0.381 |
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Øz,a |
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60.96 |
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61.5 |
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Øa,bi |
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59.72 |
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59.72 |
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Øz,bi ** |
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1.24 |
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1.8 |
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* Calculated
here from the experimental diagonal nqcc's and the calculated off-diagonal
nqcc. |
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** The z-axis makes an angle of 1.24o
with the external bisector ( 'bi' ) of the C(6)N(1)C(2) angle, and tilts
toward C(2). |
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| Table 2. 3-Fluoropyridine and Pyridine. Molecular structure parameters, ropt (Å
and degrees). |
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3-F-Pyridine |
Pyridine |
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N(1)C(2) |
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1.3303 |
1.3336 |
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C(2)C(3) |
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1.3874 |
1.3904 |
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C(3)C(4) |
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1.3818 |
1.3885 |
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C(4)C(5) |
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1.3888 |
1.3885 |
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C(5)C(6) |
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1.3904 |
1.3904 |
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C(6)N(1) |
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1.3333 |
1.3336 |
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C(2)H(2) |
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1.0869 |
1.0880 |
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C(3)F(3) |
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1.3401 |
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C(4)H(4) |
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1.0839 |
1.0851 |
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C(5)H(5) |
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1.0842 |
1.0845 |
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C(6)H(6) |
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1.0868 |
1.0880 |
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C(6)N(1)C(2) |
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117.77 |
117.03 |
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N(1)C(2)C(3) |
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122.02 |
123.80 |
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C(2)C(3)C(4) |
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120.79 |
118.44 |
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C(3)C(4)C(5) |
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116.95 |
118.50 |
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C(4)C(5)C(6) |
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118.91 |
118.44 |
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C(5)C(6)N(1) |
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123.56 |
123.80 |
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N(1)C(2)H(2) |
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118.12 |
115.94 |
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C(2)C(3)F(3) |
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119.32 |
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C(3)C(4)H(4) |
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120.37 |
120.75 |
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C(4)C(5)H(5) |
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120.68 |
121.35 |
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C(5)C(6)H(6) |
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120.38 |
120.26 |
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| Table 3. 3-Fluoropyridine. Atomic coordinates, ropt. |
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a (Å) |
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b (Å) |
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N(1) |
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1.1926 |
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1.1921 |
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C(2) |
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0.1376 |
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1.1727 |
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C(3) |
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0.8560 |
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0.0142 |
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C(4) |
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0.2067 |
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1.2340 |
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C(5) |
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1.1819 |
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1.2080 |
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C(6) |
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1.8310 |
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0.0216 |
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H(2) |
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0.6637 |
- |
2.1238 |
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F(3) |
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2.1954 |
- |
0.0295 |
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H(4) |
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0.7747 |
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2.1572 |
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H(5) |
- |
1.7525 |
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2.1299 |
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H(6) |
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2.9168 |
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0.0699 |
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| Table 4. 3-Fluoropyridine. Rotational Constants
(MHz). |
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Calc ropt |
Expt. [1] |
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A |
5874.8 |
5829.66(2) |
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B |
2649.7 |
2637.465(7) |
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C |
1826.1 |
1815.648(8) |
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[1] S.D.Sharma and S.Doraiswamy, J.Mol.Spectrosc. 59,216(1976). |
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Related ... |
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M.J.S.Dewar, Y.Yamaguchi, S.Doraiswamy, S.D.Sharma, and S.H.Suck,
Chem.Phys. 41,21(1979). |
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S.D.Sharma and S.Doraiswamy, Chem.Phys.Lett. 41,192(1976). |
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Pyridine |
2-Chloropyridine |
3-Chloropyridine |
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2-Fluoropyridine |
4-Fluoropyridine |
4-Chloropyridine |
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2-Bromopyridine |
3-Bromopyridine |
4-Bromopyridine |
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Table of Contents
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Molecules/Nitrogen |
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3MFP.html |
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Last
Modified 6 Dec 2003 |
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