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CF3(CF2)3CF2CN
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Nitrogen |
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Nuclear
Quadrupole Coupling Constants |
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in n-Perfluoropentyl transoid
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Calculation of the nitrogen nqcc's in n-perfluoropentyl cyanide, transoid
was made on structures given by
B3P86/6-31G(2d) optimization (ropt), and on this same
structure but with empirically derived
equilibrium CF, C-C, and CN bond lengths
(~ re).
These calculated nqcc's are given in Table 1. Structure
parameters are
given in
Table 2, rotational constants and electric dipole moments in Table 3. |
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In Table 1,
subscripts a,b,c refer to
principal axes of the inertia tensor; subscripts x,y,z to principal
axes
of the nqcc tensor. Øz,CN (degrees) is the
angle between the principal z-axis of the nqcc tensor and the CN bond
axis. 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 nitrogen nqcc's,
which may be taken as an estimate of the uncertainty in the calculated
nqcc's (unertainties in the structures not-with-standing). |
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Table 1. 14N nqcc's
in n-perfluoropentyl
cyanide, transoid (MHz).
Calculation was made on ropt and ~ re structures
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ropt |
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~ re |
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Expt. |
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Xaa |
- |
2.448 |
- |
2.442 |
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Xbb |
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0.351 |
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0.348 |
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Xcc |
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2.096 |
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2.094 |
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|Xab| |
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3.170 * |
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3.164 * |
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|Xac| |
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1.058 |
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1.053 |
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|Xbc| |
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0.736 |
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0.735 |
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RSD |
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0.030 (1.3 %) |
0.030 (1.3 %) |
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Xxx |
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2.323 |
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2.318 |
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Xyy |
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2.433 |
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2.428 |
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Xzz |
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4.756 |
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4.746 |
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ETA |
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0.0231 |
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0.0231 |
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Øz,CN |
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0.39 |
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0.37 |
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* The algebraic sign of the product XabXacXbc is
negative. |
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| Table 2.
n-Perfluoropentyl Cyanide, transoid.
Selected structure parameters, ropt and ~
re (Å and degrees). Complete
structures are given here in
Z-matrix format. |
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ropt |
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~ re |
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| C(1)C(2) |
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1.5469 |
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1.5456 |
| C(2)C(3) |
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1.5506 |
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1.5491 |
| C(3)C(4) |
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1.5527 |
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1.5511 |
| C(4)C(5) |
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1.5519 |
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1.5504 |
| C(5)C(6) |
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1.4788 |
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1.4805 |
| C(6)N(7) |
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1.1534 |
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1.1544 |
| C(1)C(2)C(3) |
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113.91 |
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113.91 |
| C(2)C(3)C(4) |
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112.79 |
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112.79 |
| C(3)C(4)C(5) |
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113.76 |
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113.76 |
| C(4)C(5)C(6) |
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110.10 |
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110.10 |
| C(5)C(6)N(7) |
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179.48 |
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179.48 |
| C(1)C(2)C(3)C(4) |
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163.56 |
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163.56 |
| C(2)C(3)C(4)C(5) |
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162.42 |
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162.42 |
| C(3)C(4)C(5)C(6) |
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169.07 |
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169.07 |
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C(4)C(5)C(6)N(7) |
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64.86 |
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64.86 |
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| Table 3.
n-Perfluoropentyl Cyanide, transoid.
Rotational
Constants (MHz) and Dipole Moments (D). |
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ropt |
~ re |
Expt. |
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A |
954.0 |
950.0 |
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B |
278.0 |
278.1 |
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C |
268.9 |
269.0 |
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|µa| |
1.28 |
1.26 |
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|µb| |
0.74 |
0.74 |
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|µc| |
0.21 |
0.21 |
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Order of the energies of the several
conformers of n-perfluoropentyl cyanide is Etransoid(0) <
EGA(0.47) < EAA(3.04 kJ/mol). These are
energies calculated at the B3PW91/6-311+G(df) level of theory on the
B3P86/6-31G(2d) optimized structures. |
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The AA (all trans, Cs) conformer,
with one imaginary frequency, is a saddle point connecting two lower
energy minima [1]. It is not, itself, a local minimum. |
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[1] J.B.Foresman and AE.Frisch,
Exploring Chemistry with Electronic Structure Methods, 2nd ed.,
Gaussian, Inc. Pittsburgh, PA 1995-96. |
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n-Perfluoropentyl
Cyanide GA |
n-Perfluorobutyl
Cyanide transoid |
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n-Perfluorohexyl
Cyanide transoid |
n-Perfluoroheptyl
Cyanide transoid |
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Table of Contents |
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Molecules/Nitrogen |
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C5F11CN_transoid.html |
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Last
Modified 4 June 2010 |
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