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2-F-C5H4N
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in 2-Fluoropyridine |
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Calculation of the nitrogen nqcc's
in 2-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 B3PW91/6-311+G(df,pd) model for
calculation of the nqcc's. |
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Table 1. Nitrogen nqcc's in 2-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 |
- |
0.094 |
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0.02(5) |
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Xbb |
- |
2.696 |
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2.80(5) |
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Xcc |
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2.790 |
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2.82(5) |
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|Xab| |
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2.782 |
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RMS |
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0.08 (4.0 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.676 |
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1.70 * |
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Xyy |
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2.790 |
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2.82 |
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Xzz |
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4.466 |
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4.52 |
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ETA |
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0.249 |
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0.248 |
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Øz,a |
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57.53 |
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58.3 |
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Øa,bi |
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57.08 |
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57.08 |
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Øz,bi ** |
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0.44 |
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1.2 |
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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 0.44o
with the external bisector ( 'bi' ) of the C(6)N(1)C(2) angle, and tilts
toward C(6). |
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| Table 2. 2-Fluoropyridine and Pyridine. Molecular structure parameters, ropt (Å
and degrees). |
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2-F-Pyridine |
Pyridine |
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N(1)C(2) |
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1.3087 |
1.3336 |
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C(2)C(3) |
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1.3894 |
1.3904 |
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C(3)C(4) |
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1.3851 |
1.3885 |
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C(4)C(5) |
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1.3922 |
1.3885 |
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C(5)C(6) |
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1.3864 |
1.3904 |
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C(6)N(1) |
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1.3375 |
1.3336 |
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C(2)F(2) |
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1.3363 |
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C(3)H(3) |
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1.0828 |
1.0845 |
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C(4)H(4) |
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1.0847 |
1.0851 |
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C(5)H(5) |
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1.0833 |
1.0845 |
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C(6)H(6) |
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1.0867 |
1.0880 |
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C(6)N(1)C(2) |
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116.49 |
117.03 |
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N(1)C(2)C(3) |
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126.04 |
123.80 |
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C(2)C(3)C(4) |
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116.57 |
118.44 |
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C(3)C(4)C(5) |
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119.18 |
118.50 |
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C(4)C(5)C(6) |
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118.25 |
118.44 |
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C(5)C(6)N(1) |
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123.46 |
123.80 |
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N(1)C(2)F(2) |
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115.92 |
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C(2)C(3)H(3) |
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120.45 |
120.21 |
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C(3)C(4)H(4) |
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120.10 |
120.75 |
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C(4)C(5)H(5) |
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121.35 |
121.35 |
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C(5)C(6)H(6) |
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120.77 |
120.26 |
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| Table 3. 2-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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0.2536 |
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1.1718 |
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C(2) |
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0.8136 |
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0.0110 |
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C(3) |
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0.1479 |
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1.2306 |
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C(4) |
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1.2363 |
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1.1811 |
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C(5) |
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1.8712 |
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0.0579 |
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C(6) |
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1.0836 |
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1.1989 |
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F(2) |
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2.1498 |
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0.0247 |
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H(3) |
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0.7044 |
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2.1595 |
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H(4) |
- |
1.8135 |
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2.0994 |
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H(5) |
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2.9516 |
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0.1377 |
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H(6) |
- |
1.5361 |
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2.1869 |
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| Table 4. 2-Fluoropyridine. Rotational Constants
(MHz). |
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Calc ropt |
Expt. [1] |
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A |
5915.9 |
5870.921(7) |
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B |
2712.2 |
2699.940(6) |
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C |
1859.7 |
1849.271(4) |
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[1] S.D.Sharma, S.Doraiswamy, H.Legell, H.Mäder, and D.Sutter,
Z.Naturforsch. 26a,1342(1971). |
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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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3-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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2MFP.html |
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Last
Modified 15 Nov 2003 |
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