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4-CHO-C5H4N
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in 4-Pyridine Carbaldehyde |
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The molecular structure of 4-pyridine
carbaldehyde was optimized at the B3P86/6-31G(3d,3p) level of theory.
Cs
symmetry was assumed. On this structure calculation was made of
the nitrogen nqcc's. These are compared with the experimental
nqcc's of Stryjewski et al. [1] in Table 1. Structure parameters
are given in Table 2, atomic coordinates in Table 3, 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, subscripts 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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RMS is the root mean square
differene between calculated and experimental nqcc's (percent of
average experimental nqcc). 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 4-Pyridine Carbaldehyde (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 |
Xaa |
- |
4.915 |
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4.900(8) |
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Xbb |
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1.163 |
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1.179(9) |
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Xcc |
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3.752 |
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3.721(9) |
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|Xab| |
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1.131 |
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RMS |
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0.022 (0.7 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.367 |
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1.383 * |
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Xyy |
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3.752 |
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3.721 |
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Xzz |
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5.119 |
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5.104 |
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ETA |
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0.466 |
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0.458 |
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Øz,a |
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10.21 |
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10.20 |
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Øa,bi |
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10.12 |
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10.12 |
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Øz,bi ** |
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0.08 |
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0.08 |
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* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc. |
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** The z-axis makes an angle of 0.08o
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. 4-Pyridine Carbaldehyde and Pyridine. Molecular structure parameters, ropt (Å
and degrees). |
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4-CHO-Pyridine |
Pyridine |
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N(1)C(2) |
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1.3366 |
1.3336 |
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C(2)C(3) |
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1.3869 |
1.3904 |
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C(3)C(4) |
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1.3936 |
1.3885 |
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C(4)C(5) |
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1.3910 |
1.3885 |
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C(5)C(6) |
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1.3908 |
1.3904 |
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C(6)N(1) |
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1.3319 |
1.3336 |
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C(2)H(2) |
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1.0871 |
1.0880 |
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C(3)H(3) |
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1.0841 |
1.0845 |
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C(5)H(5) |
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1.0859 |
1.0845 |
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C(6)H(6) |
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1.0872 |
1.0880 |
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C(6)N(1)C(2) |
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117.54 |
117.03 |
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N(1)C(2)C(3) |
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123.72 |
123.80 |
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C(2)C(3)C(4) |
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118.19 |
118.44 |
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C(3)C(4)C(5) |
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118.66 |
118.50 |
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C(4)C(5)C(6) |
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118.48 |
118.44 |
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C(5)C(6)N(1) |
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123.41 |
123.80 |
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N(1)C(2)H(2) |
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115.85 |
115.94 |
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C(2)C(3)H(3) |
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121.85 |
120.21 |
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C(6)C(5)H(5) |
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120.69 |
120.21 |
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N(1)C(6)H(6) |
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116.10 |
115.94 |
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C(4)C |
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1.4813 |
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CO |
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1.2069 |
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CH |
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1.1111 |
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C(3)C(4)C |
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121.10 |
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C(4)C=O |
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124.14 |
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C(4)CH |
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114.79 |
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| Table 3. 4-Pyridine Carbaldehyde. 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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2.2384 |
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0.2577 |
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C(2) |
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1.3554 |
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1.2611 |
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C(3) |
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0.0191 |
- |
1.0770 |
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C(4) |
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0.5085 |
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0.2278 |
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C(5) |
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0.4000 |
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1.2812 |
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C(6) |
- |
1.7588 |
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0.9848 |
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H(2) |
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1.7767 |
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2.2632 |
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H(3) |
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0.7084 |
- |
1.9138 |
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H(5) |
- |
0.0574 |
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2.3116 |
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H(6) |
- |
2.4974 |
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1.7826 |
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C |
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1.9648 |
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0.4987 |
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O |
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2.8134 |
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0.3594 |
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H |
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2.2384 |
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1.5756 |
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| Table 4. 4-Pyridine Carbaldehyde. Rotational Constants
(MHz). |
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Calc ropt |
Expt. [1] |
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A |
5560.6 |
5519.114(3) |
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B |
1568.0 |
1559.205(2) |
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C |
1223.1 |
1216.129(2) |
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[1] D.Stryjewski, N.Heineking, and H.Dreizler, Z.Naturforsch.
44a,67(1989). |
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See also ... |
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K.Georgiou and G.Roussy, J.Mol.Spectrosc. 82,176(1980). |
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Pyridine |
2-Pyridine Carbaldehyde |
3-Pyridine Carbaldehyde |
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4-Fluoropyridine |
4-Chloropyridine |
4-Bromopyridine |
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4-Cyanopyridine |
4-Methylpyridine |
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Table of Contents
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Molecules/Nitrogen |
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4pyrCHO.html |
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Last
Modified 17 Nov 2003 |
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