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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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Nitrogen
nqcc's in 3-fluoropyridine were first determined in 1976 by Sharma and
Doraiswamy [1] and revisited in 2012 by van Eijk et al. [2]. |
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Calculation of the nitrogen nqcc's
was made here on a molecular structure given by
B3P86/6-31G(3d,3p) optimization. These are compared with the
experimental nqcc's [2] in Table 1. Structure parameters are
given in Table 2, atomic coordinates in Table 3, rotational
constants and centrifugal distortion 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. [2] |
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14N |
Xaa |
- |
0.089 |
- |
0.1003(10) *
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Xbb |
- |
2.700 |
- |
2.7363(9)
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Xcc |
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2.789 |
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2.8365(9)
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|Xab| |
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2.779 |
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2.76(5)
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RMS |
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0.035 (1.8 %) |
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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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1.640(45) * |
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Xyy |
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2.789 |
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2.8365(9) |
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Xzz |
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4.465 |
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4.477(45) |
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ETA |
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0.249 |
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0.267(10) |
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Øz,a |
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57.58 |
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57.76(20) |
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Øa,bi |
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57.09 |
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Øz,bi ** |
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0.49 |
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* Calculated
here from the experimental 1.5(Xaa) = -0.1504(15) and
0.25(Xbb - Xcc) = -1.3932(4) MHz using Kisiel's
QDIAG.f program. |
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** The z-axis makes an angle of
0.49o with the external bisector ( 'bi' ) of the
C(6)N(1)C(2) angle. |
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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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1.3082 |
1.3336 |
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C(2)C(3) |
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1.3896 |
1.3904 |
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C(3)C(4) |
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1.3850 |
1.3885 |
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C(4)C(5) |
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1.3925 |
1.3885 |
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C(5)C(6) |
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1.3861 |
1.3904 |
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C(6)N(1) |
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1.3378 |
1.3336 |
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C(2)F(2) |
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1.3368 |
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C(3)H(3) |
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1.0829 |
1.0845 |
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C(4)H(4) |
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1.0849 |
1.0851 |
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C(5)H(5) |
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1.0835 |
1.0845 |
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C(6)H(6) |
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1.0869 |
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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126.08 |
123.80 |
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C(2)C(3)C(4) |
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116.54 |
118.44 |
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C(3)C(4)C(5) |
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119.20 |
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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123.45 |
123.80 |
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N(1)C(2)F(2) |
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115.94 |
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C(2)C(3)H(3) |
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120.48 |
120.21 |
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C(3)C(4)H(4) |
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120.12 |
120.75 |
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C(4)C(5)H(5) |
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121.33 |
121.35 |
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C(5)C(6)H(6) |
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120.80 |
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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0.2534 |
- |
1.1718 |
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C(2) |
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0.8132 |
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0.0105 |
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C(3) |
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0.1484 |
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1.2307 |
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C(4) |
- |
1.2357 |
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1.1813 |
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C(5) |
- |
1.8713 |
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0.0577 |
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C(6) |
- |
1.0842 |
- |
1.1987 |
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F(2) |
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2.1500 |
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0.0245 |
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H(3) |
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0.7050 |
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2.1596 |
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H(4) |
- |
1.8133 |
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2.0997 |
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H(5) |
- |
2.9519 |
- |
0.1367 |
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H(6) |
- |
1.5366 |
- |
2.1869 |
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| Table 4.
2-Fluoropyridine. Rotational Constants (MHz) and
Centrifugal Distortion Constants * (kHz). |
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Calc ropt |
Expt. [2] |
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A |
5915.7 |
5870.88105(19) |
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B |
2712.1 |
2699.98571(10) |
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C |
1859.6 |
1849.24259(7) |
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Delta_J
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0.137
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0.149(2)
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Delta_JK |
0.229
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0.232(8)
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Delta_K |
0.909
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0.922(19)
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delta_J |
0.0449
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0.0488(11)
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delta_K |
0.384
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0.371(11)
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*
B3LYP/cc-pVTZ opt freq(vibrot) |
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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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[2] C.W.
van Dijk, M. Sun, and J. van Wijngaarden, J.Phys.Chem. A 116,4082(2012). |
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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 3 April 2012
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