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(CH3)2NH |
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in Dimethylamine |
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Calculation of the nitrogen
nqcc's in dimethylamine was made on the substitution structure of
Wollrab and Laurie [1]. These are compared in Table 1 with the
experimental
nqcc's [1]. In Tables 2 and 3, nqcc's calculated on structures
given by mPW1PW91 and MP2 optimizations each in conjunction with
6-311++G(3df,3pd) and aug-cc-pVTZ bases are compared with the
experimental nqcc's. Structure parameters are given in Table 4. |
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In Tables 1 - 3, RMS is the root mean square difference
between calculated and experimental diagonal 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 nitrogen nqcc's. |
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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 x-axis is chosen coincident with the
inertia a-axis, these are perpendicular to the molecular symmetry plane.
Ø (degrees) is the angle between its subscripted
parameters. ETA = (Xxx - Xyy)/Xzz. |
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Table 1. Nitrogen
nqcc's in (CH3)2NH (MHz). Calculation was made on the substitution structure [1]. |
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Calc. |
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Expt. [1] |
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14N |
Xaa |
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2.948 |
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3.04(12) |
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Xbb |
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0.793 |
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0.93(12) |
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Xcc |
- |
3.742 |
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3.97(24) |
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|Xbc| |
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2.981 |
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2.48(40) |
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RMS |
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0.16 (6.1 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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2.948 |
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3.04(12) |
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Xyy |
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2.271 |
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2.01(50) |
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Xzz |
- |
5.220 |
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5.05(40) |
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ETA |
- |
0.130 |
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0.2 |
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Øz,c |
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26.4 |
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Øc,NH |
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42.8 |
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Øz,NH |
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69.2 |
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Table 2. 14N nqcc's in (CH3)2NH
(MHz). Calculation was made on the MP2/ and mPW1PW91/6-311+G(3d,3p) optimized structures. |
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MP2
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mPW1PW91 |
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Expt. [1] |
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Xaa |
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2.935 |
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2.983 |
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3.04(12) |
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Xbb |
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0.809 |
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0.955 |
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0.93(12) |
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Xcc |
- |
3.744 |
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3.938 |
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3.97(24) |
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|Xbc| |
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2.985 |
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2.956 |
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2.48(40) |
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RMS |
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0.16 (6.0 %) |
0.040 (1.5 %) |
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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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2.935 |
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2.983 |
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3.04(12) |
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Xyy |
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2.289 |
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2.345 |
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2.01(50) |
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Xzz |
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5.222 |
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5.328 |
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5.05(40) |
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ETA |
- |
0.124 |
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0.120 |
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0.2 |
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Øz,c |
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26.34 |
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25.19 |
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Øc,NH |
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42.88 |
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45.29 |
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Øz,NH |
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69.22
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70.48 |
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Table 3. 14N nqcc's in (CH3)2NH
(MHz). Calculation was made on the MP2/ and mPW1PW91/aug-cc-pVTZ optimized structures. |
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MP2
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mPW1PW91 |
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Expt. [1] |
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Xaa |
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2.934 |
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2.988 |
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3.04(12) |
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Xbb |
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0.798 |
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0.967 |
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0.93(12) |
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Xcc |
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3.732 |
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3.956 |
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3.97(24) |
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|Xbc| |
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2.987 |
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2.949 |
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2.48(40) |
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RMS |
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0.22 (8.2 %) |
0.038 (1.4 %) |
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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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2.934 |
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2.988 |
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3.04(12) |
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Xyy |
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2.281 |
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2.347 |
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2.01(50) |
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Xzz |
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5.215 |
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5.336 |
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5.05(40) |
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ETA |
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0.125 |
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0.120 |
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0.2 |
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Øz,c |
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26.42 |
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25.08 |
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Øc,NH |
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42.67 |
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45.45 |
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Øz,NH |
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69.08
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70.52 |
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| Table 4. Dimethylamine. Molecular structure parameters. Substitution and ab initio. (Å
and degrees). For dihedral angles, see Z-Matrix. |
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rs [1] |
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HN |
1.019(7) |
| NC |
1.462(5) |
| CH(5) |
1.084(5) |
| CH(7) |
1.098(4) |
| CH(9) |
1.098(4) |
| CNC |
112.2(2) |
| HNC |
108.9(3) |
| NCH(5) |
109.7(3) |
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NCH(7) |
108.2(3) |
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NCH(9) |
113.8(3) |
| Ab initio Structures. Z-Matrix. |
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6-311++G(3df,3pd) |
aug-cc-pVTZ |
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MP2 |
mPW1PW91 |
MP2 |
mPW1PW91 |
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| HN |
1.0114 |
1.0093 |
1.0123 |
1.0091 |
| NC |
1.4540 |
1.4458 |
1.4562 |
1.4463 |
| CH(5) |
1.0877 |
1.0894 |
1.0884 |
1.0896 |
| CH(7) |
1.0894 |
1.0914 |
1.0898 |
1.0916 |
| CH(9) |
1.0982 |
1.1009 |
1.0988 |
1.1010 |
| CNC |
111.57 |
113.03 |
111.38 |
113.06 |
| HNC |
109.18 |
109.90 |
109.14 |
109.97 |
| NCH(5) |
109.84 |
109.95 |
109.90 |
109.92 |
| NCH(7) |
108.99 |
109.45 |
108.93 |
109.42 |
| NCH(9) |
113.45 |
113.91 |
113.39 |
113.93 |
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[1] J.E.Wollrab and V.W.Laurie, J.Chem.Phys.
48,5058(1968). |
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CH2NH |
CF2NH |
Ethylenimine |
Pyrrolidine |
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trans-Ethanimine |
cis-Ethanimine |
Piperidine |
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trans-syn-Propenimine |
trans-anti-Propenimine |
Morpholine |
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Table of Contents |
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Molecules/Nitrogen |
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CH32NH.html |
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Last
Modified 3 Jan 2006 |
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