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4-F-C4N2H3
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in 4-Fluoropyrimidine |
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Nitrogen nqcc's in 4-fluoropyrimidine
were calculated on the structure given by B3P86/6-31G(3d,3p) optimization.
These are given in Tables 1 - 2. Structure parameters are given in
Table 3, atomic coordinates in Table 4, and rotational constants in Table 5. |
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In Tables 1 - 2, 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. N(1) nqcc's in 4-Fluoropyrimidine (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(1) |
Xaa |
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4.587 |
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Xbb |
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1.525 |
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Xcc |
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3.062 |
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|Xab| |
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0.322 |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.542 |
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Xyy |
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3.062 |
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Xzz |
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4.604 |
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ETA |
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0.330 |
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Øz,a |
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3.01 |
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Øa,bi |
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3.74 |
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Øz,bi * |
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0.72 |
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* The z-axis makes an angle of 0.72o
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. N(3) nqcc's in 4-Fluoropyrimidine (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(3) |
Xaa |
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0.041 |
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Xbb |
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2.730 |
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Xcc |
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2.689 |
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|Xab| |
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2.618 |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.617 |
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Xyy |
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2.689 |
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Xzz |
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4.306 |
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ETA |
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0.249 |
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Øz,a |
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58.95 |
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Øa,bi |
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58.71 |
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Øz,bi * |
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0.24 |
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* The z-axis makes an angle of 0.24o
with the external bisector ( 'bi' ) of the C(2)N(3)C(4) angle, and
tilts toward C(2). |
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| Table 3. 4-Fluoropyrimidine. Molecular structure parameters,
ropt (Å and degrees). |
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N(1)C(2) |
1.3269 |
N(1)C(2)N(3) |
127.12 |
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C(2)N(3) |
1.3366 |
C(2)N(3)C(4) |
115.03 |
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N(3)C(4) |
1.3094 |
N(3)C(4)C(5) |
124.60 |
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C(4)C(5) |
1.3876 |
C(4)C(5)C(6) |
114.69 |
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C(5)C(6) |
1.3842 |
C(5)C(6)N(1) |
122.94 |
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C(6)N(1) |
1.3370 |
C(6)N(1)C(2) |
115.62 |
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C(2)H(2) |
1.0867 |
N(1)C(2)H(2) |
116.86 |
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C(4)F(4) |
1.3285 |
N(1)C(6)H(6) |
116.42 |
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C(5)H(5) |
1.0821 |
C(6)C(5)H(5) |
121.91 |
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C(6)H(6) |
1.0870 |
C(5)C(4)F(4) |
118.96 |
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| Table 4. 4-Fluoropyrimidine. 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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1.8606 |
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0.0590 |
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C(2) |
- |
1.0821 |
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1.3357 |
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N(3) |
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0.2542 |
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1.1614 |
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C(4) |
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0.8329 |
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0.0132 |
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C(5) |
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0.1564 |
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1.2247 |
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C(6) |
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1.2236 |
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1.1164 |
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H(2) |
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1.5791 |
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2.1000 |
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F(4) |
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2.1613 |
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0.0182 |
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H(5) |
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0.6794 |
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2.1719 |
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H(6) |
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1.8491 |
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2.0055 |
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| Table 5. 4-Fluoropyrimidine. Rotational Constants
(MHz). |
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Calc. ropt |
Expt. |
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A |
6272.3 |
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B |
2729.0 |
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C |
1901.6 |
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Pyrimidine |
4-Chloropyrimidine |
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2-Fluoropyrimidine |
5-Fluoropyrimidine |
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Table of Contents
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Molecules/Nitrogen |
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4FPRM.html |
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Last
Modified 23 Feb 2004 |
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