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Phthalazine
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in
Phthalazine |
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Nitrogen nqcc tensors in phthalazine
were calculated on a molecular structure optimized at the
B3P86/6-31G(3d,3p) level of theory. These calculated nqcc's are
compared with the experimental values of McNaughton et al. [1] 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. The nqcc y-axis is chosen coincident
with the inertia c-axis, these are perpendicular to the plane of the
molecule. Ø (degrees) is the angle between its subscripted
parameters. ETA = (Xxx - Xyy)/Xzz. |
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RMS is the root mean square
difference between calculated and experimental nqcc's (percentage of
average experimental nqcc). RSD is the residual stand deviation
of calibration 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 Phthalazine (MHz). Calculation was made
on the B3P86/6-31G(3d,3p) ropt structure. |
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Calc. |
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Expt. [1] |
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14N(1,2) |
Xaa |
- |
4.716 |
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4.72845(136) |
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Xbb |
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1.723 |
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1.8501 * |
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Xcc |
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2.993 |
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2.8783 * |
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Xab |
± |
2.470 |
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2.350(94) |
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RMS |
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0.099 (3.1 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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2.561 |
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Xyy |
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2.993 |
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Xzz |
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5.554 |
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ETA |
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0.0776 |
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Øz,a |
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18.75 |
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Øa,bi |
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30.25
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Øz,bi** |
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11.50
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* Calculated here from experimental Xaa and
Xbb - Xcc = -1.0283(30) MHz. |
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** The z-axis makes an angle of
11.50o
with the external bisector ('bi') of the NNC angle and tilts toward the
adjacent nitrogen atom. |
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| Table 2. Phthalazine and
Pyridazine. Selected molecular structure parameters,
B3P86/6-31G(3d,3p) ropt (Å and degrees).
The complete structure of phthalazine is given here in Z-matrix format. |
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Phthalazine |
Pyridazine |
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N(1)N(2) |
1.3569 |
1.3251 |
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N(2)C(3) |
1.3089 |
1.3314 |
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N(1)N(2)C(3) |
119.49 |
119.44 |
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| Table 3.
Phthalazine, ropt.
Rotational constants (MHz) and B3PW91/6-311+G(df,pd) calculated
dipole moments (D). |
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Calc. |
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Expt. [1] |
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A |
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3291.67 |
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3263.94094(123) |
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B |
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1243.76 |
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1236.018430(35) |
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C |
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902.68 |
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896.743486(41) |
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µa |
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5.4 |
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[1] D.McNaughton, P.D.Godfrey,
M.K.Jahn, D.A.Dewald, and J.-U.Grabow, J.Chem.Phys. 134,154305(2011). |
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Pyridazine |
Quinazoline |
Quinoxaline |
1,10-Phenanthroline |
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Acridine |
Quinoline |
Isoquinoline |
Phenanthridine |
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Table of Contents |
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Molecules/Nitrogen |
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Phthalazine.html |
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Last
Modified 20 April 2011 |
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