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C5F5N
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in Pentafluoropyridine |
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Nitrogen nqcc's in pentafluoropyridine were first determined
by Doraiswamy and Sharma [1], and redetermined with improved resolution by Heineking and Dreizler [2]. |
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Calculation was made here of the
nitrogen nqcc's on a 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, and rotational constants in
Table 4. |
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In Table 1, RMS is the root mean square difference
between calculated and experimental nqcc's (percentage of the average
of the magnitudes of the experimental nqcc's). 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 Pentafluoropyridine (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 |
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2.017 |
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1.97(1) |
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Xbb |
- |
3.878 |
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3.94(1) |
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Xcc |
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1.861 |
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1.97(1) |
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ETA * |
- |
0.040 |
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RMS |
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0.08 (2.9 %) |
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RSD |
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0.030 (1.3 %) |
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* ETA = (Xaa - Xcc)/Xbb
= (Xxx - Xyy)/Xzz. |
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| Table 2. Pentachloropyridine, Pentafluoropyridine, and Pyridine. Molecular structure parameters, ropt (Å
and degrees). |
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C5X5N |
C5Cl5N |
C5F5N |
C5H5N |
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N(1)C(2) |
1.3158 |
1.3104 |
1.3336 |
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C(2)C(3) |
1.3994 |
1.3878 |
1.3904 |
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C(3)C(4) |
1.4005 |
1.3898 |
1.3885 |
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C(2)X(2) |
1.7200 |
1.3226 |
1.0880 |
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C(3)X(3) |
1.7073 |
1.3244 |
1.0845 |
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C(4)X(4) |
1.7052 |
1.3178 |
1.0851 |
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C(6)N(1)C(2) |
119.64 |
118.46 |
117.03 |
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N(1)C(2)C(3) |
123.15 |
123.80 |
123.80 |
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C(2)C(3)C(4) |
117.25 |
117.31 |
118.44 |
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C(3)C(4)C(5) |
119.55 |
119.31 |
118.50 |
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N(1)C(2)X(2) |
116.53 |
117.59 |
115.94 |
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C(4)C(3)X(3) |
121.10 |
120.60 |
121.35 |
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| Table 3. Pentafluoropyridine. 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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0.0 |
- |
1.6430 |
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C(2,6) |
± |
1.1260 |
- |
0.9726 |
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C(3,5) |
± |
1.1994 |
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0.4132 |
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C(4) |
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0.0 |
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1.1153 |
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F(2,6) |
± |
2.2520 |
- |
1.6663 |
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F(3,5) |
± |
2.3572 |
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1.0563 |
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F(4) |
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0.0 |
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2.4332 |
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| Table 4. Pentafluoropyridine. Rotational Constants
(MHz). |
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Calc ropt |
Expt. [2] |
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A |
1486.8 |
1481.5813(3) |
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B |
1078.0 |
1075.3725(2) |
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C |
624.9 |
623.1115(4) |
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[1] S.Doraiswamy and S.D.Sharma, Chem.Phys. 6,76(1974). |
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[2] N.Heineking and H.Dreizler, Z.Naturforsch.
42a,207(1987). |
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Pyridine |
Pentachloropyridine
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2,6-Difluoropyridine |
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2-Fluoropyridine |
2,3-Difluoropyridine |
3,4-Difluoropyridine |
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3-Fluoropyridine |
2,4-Difluoropyridine |
3,5-Difluoropyridine |
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4-Fluoropyridine |
2,5-Difluoropyridine |
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Table of Contents
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Molecules/Nitrogen |
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C5F5N.html |
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Last
Modified 15 Nov 2003 |
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