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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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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 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. [2] |
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14N |
Xaa |
- |
0.035 |
-
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0.0347(10) *
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Xbb |
- |
3.471 |
- |
3.4659(9)
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Xcc |
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3.506 |
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3.5005(9)
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|Xab| |
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2.751 |
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2.751(7)
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RMS |
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0.005 (0.20 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.491 |
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1.492(6) *
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Xyy |
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3.506 |
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3.5005(9)
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Xzz |
- |
4.997 |
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4.992(6)
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ETA |
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0.403 |
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0.402(1)
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Øz,a |
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60.99
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60.97(3)
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Øa,bi |
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59.72
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Øz,bi ** |
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1.27
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* Calculated
here from the experimental 1.5(Xaa) = -0.0520(15) and
0.25(Xbb - Xcc) = -1.7416(4) MHz using Kisiel's
QDIAG.f program.
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** The z-axis makes an angle of
1.27o with the external bisector ( 'bi' ) of the
C(6)N(1)C(2) angle. |
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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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1.3308 |
1.3336 |
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C(2)C(3) |
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1.3871 |
1.3904 |
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C(3)C(4) |
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1.3819 |
1.3885 |
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C(4)C(5) |
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1.3887 |
1.3885 |
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C(5)C(6) |
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1.3906 |
1.3904 |
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C(6)N(1) |
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1.3331 |
1.3336 |
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C(2)H(2) |
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1.0870 |
1.0880 |
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C(3)F(3) |
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1.3403 |
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C(4)H(4) |
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1.0840 |
1.0851 |
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C(5)H(5) |
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1.0843 |
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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117.78 |
117.03 |
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N(1)C(2)C(3) |
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121.99 |
123.80 |
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C(2)C(3)C(4) |
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120.81 |
118.44 |
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C(3)C(4)C(5) |
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116.96 |
118.50 |
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C(4)C(5)C(6) |
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118.89 |
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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118.08 |
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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120.36 |
120.75 |
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C(4)C(5)H(5) |
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120.71 |
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) |
- |
1.1927 |
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1.1920 |
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C(2) |
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0.1380 |
- |
1.1728 |
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C(3) |
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0.8558 |
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0.0140 |
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C(4) |
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0.2066 |
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1.2339 |
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C(5) |
- |
1.1819 |
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1.2081 |
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C(6) |
- |
1.8310 |
- |
0.0217 |
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H(2) |
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0.6633 |
- |
2.1244 |
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F(3) |
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2.1955 |
- |
0.0292 |
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H(4) |
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0.7748 |
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2.1571 |
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H(5) |
- |
1.7529 |
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2.1300 |
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H(6) |
- |
2.9168 |
- |
0.0702 |
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| Table 4.
3-Fluoropyridine. Rotational Constants (MHz)
and Centrifugal Distortion Constants * (kHz). |
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Calc ropt |
Expt. [2] |
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A |
5874.4 |
5829.70195(13) |
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B |
2649.6 |
2637.49103(7) |
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C |
1826.0 |
1815.65619(6) |
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Delta_J
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0.135
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0.1411(17)
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Delta_JK
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0.302
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0.296(6)
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Delta_K
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0.839
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0.869(17)
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delta_J
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0.0433
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0.0450(5)
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delta_K
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0.411
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0.416(7)
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*
B3LYP/cc-pVTZ opt freq(vibrot)
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[1] S.D.Sharma and S.Doraiswamy,
J.Mol.Spectrosc. 59,216(1976). |
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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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D.Hübner, M.Stolze, and D.H.Sutter, Z.Naturforsch. 36a,332(1981).
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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 2 April 2012
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