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3,4-F2-C5H3N
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in 3,4-Difluoropyridine |
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Calculation of the nitrogen nqcc's
in 3,4-difluoropyridine was made here on a molecular structure given by
B3P86/6-31G(3d,3p) optimization. These are given 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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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 3,4-Difluoropyridine (MHz). Calculation
was made on the B3P86/6-31G(3d,3p) ropt structure. |
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Calc. |
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Expt. |
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14N |
Xaa |
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3.235 |
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Xbb |
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0.043 |
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Xcc |
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3.192 |
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|Xab| |
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2.789 |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.639 |
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Xyy |
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3.192 |
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Xzz |
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4.831 |
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ETA |
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0.321 |
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Øz,a |
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29.78 |
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Øa,bi |
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28.47 |
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Øz,bi * |
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1.31 |
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* The z-axis makes an angle of 1.31o
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. 3,4-Difluoropyridine. Molecular structure parameters, ropt (Å
and degrees). |
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N(1)C(2) |
1.3318 |
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C(2)C(3) |
1.3853 |
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C(3)C(4) |
1.3879 |
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C(4)C(5) |
1.3823 |
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C(5)C(6) |
1.3904 |
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C(6)N(1) |
1.3324 |
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C(2)H(2) |
1.0871 |
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C(3)F(3) |
1.3328 |
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C(4)F(4) |
1.3286 |
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C(5)H(5) |
1.0835 |
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C(6)H(6) |
1.0865 |
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C(6)N(1)C(2) |
117.58 |
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N(1)C(2)C(3) |
122.87 |
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C(2)C(3)C(4) |
118.87 |
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C(3)C(4)C(5) |
119.02 |
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C(4)C(5)C(6) |
117.64 |
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C(5)C(6)N(1) |
124.02 |
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N(1)C(2)H(2) |
118.09 |
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C(2)C(3)F(3) |
121.04 |
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C(3)C(4)F(4) |
119.76 |
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C(4)C(5)H(5) |
120.07 |
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C(5)C(6)H(6) |
119.78 |
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| Table 3. 3,4-Difluoropyridine. 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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1.9504 |
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0.6441 |
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C(2) |
- |
0.8008 |
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1.3166 |
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C(3) |
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0.4356 |
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0.6918 |
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C(4) |
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0.4855 |
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0.6952 |
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C(5) |
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0.6984 |
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1.4088 |
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C(6) |
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1.8867 |
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0.6868 |
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F(2) |
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0.8432 |
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2.4028 |
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H(3) |
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1.5640 |
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1.4012 |
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F(4) |
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1.6618 |
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1.3127 |
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H(5) |
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0.6794 |
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2.4921 |
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H(6) |
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2.8375 |
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1.2126 |
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| Table 4. 3,4-Difluoropyridine. Rotational Constants
(MHz). |
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Calc ropt |
Expt. |
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A |
3341.9 |
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B |
2267.6 |
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C |
1350.9 |
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Pyridine |
2-Fluoropyridine |
2,3-Difluoropyridine
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3-Fluoropyridine |
4-Fluoropyridine |
2,5-Difluoropyridine |
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2,4-Difluoropyridine |
2,6-Difluoropyridine |
3,5-Difluoropyridine |
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Table of Contents
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Molecules/Nitrogen |
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34DFP.html |
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Last
Modified 26 Jan 2004 |
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