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CH3-NH-CH2CH2OH
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Nitrogen |
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Nuclear
Quadrupole Coupling Constants |
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in 2-Methylaminoethanol
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14N nqcc's in 2-methylaminoethanol were determined by Calabrese et al. [1], electric dipole moments by
Penn and Buxton [2].
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Calculation of the 14N
nuclear quadrupole coupling constant tensors, as well as the dipole miments, in each of the following conformers of the title molecule was made here on ropt molecular
structures given by MP2/6-311++G(d,p) and MP2/6-311+G(df,pd) optimization.
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Conformer gG'T
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Conformer g'GG
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EgG'T < Eg'GG by 0.15 kJ/mole at MP2/6-311+G(df,pd) level of theory.
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Calculated and experimental nitrogen
nqcc's are compared in Tables 1 and 2, rotational constants and electric dipole moments in
Table 3. Optimized structure parameters are given here in Z-Matrix format.
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In Tables 1 and 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. ETA = (Xxx - Xyy)/Xzz. Øz,NH
is angle between the z-principal axes of the nqcc tensor and the NH
bond axis. RMS is the root mean square difference between
calculated and
experiment diagonal nqcc's (percent of average magnitude of
experimental nqcc's). RSD is the calibration residual standard
deviation of the B3PW91/6-311+G(df,pd) model for calculation of the efg's/nqcc's.
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Table 1. 14N nqcc's in 2-Methylaminoethanol, conformer gG'T (MHz). Calculation was made
on (1) MP2/6-311++G(d,p) and (2) MP2/6-311+G(df,pd) ropt structures.
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Calc (1)
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Calc (2)
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Expt [1]
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Xaa |
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1.455
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1.425
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1.578(2)
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Xbb
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-
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3.488
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3.468
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-
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3.420(4) *
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Xcc
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2.033
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2.043
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1.842(4) *
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Xab
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-
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2.859
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2.871
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Xac |
-
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0.509
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-
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0.524
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Xbc |
-
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1.069
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1.087
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RMS
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0.137 (6.0 %)
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0.149 (6.5 %)
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RSD
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0.030 (1.3 %) |
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0.030 (1.3 %) |
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Xxx
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2.764 |
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2.751
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Xyy
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2.231
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2.249
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Xzz
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-
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4.995
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5.000
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ETA
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-
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0.107
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0.100
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Øz,NH
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110.9
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110.6
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* Calculated here from Xaa and Xbb - Xcc = -5.262(3) MHz
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Table 2. 14N nqcc's in 2-Methylaminoethanol, conformer g'GG (MHz). Calculation was made
on (1) MP2/6-311++G(d,p) and (2) MP2/6-311+G(df,pd) ropt structures.
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Calc (1)
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Calc (2)
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Expt [1]
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Xaa |
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0.510
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0.476
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0.510(7)
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Xbb
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-
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2.276
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2.178
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2.16(1) *
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Xcc
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1.766
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1.702
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1.65(1) *
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Xab
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3.373
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3.349
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Xac |
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0.802
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0.896
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Xbc |
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1.575
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1.674
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RMS
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0.09 (6.6 %)
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0.04 (2.6 %)
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RSD
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0.030 (1.3 %) |
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0.030 (1.3 %) |
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Xxx
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2.833 |
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2.816
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Xyy
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2.155
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2.171
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Xzz
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4.988
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4.987
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ETA
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0.136
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0.129
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Øz,NH
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109.6
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109.2
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* Calculated here from Xaa and Xbb - Xcc = -3.81(1) MHz
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| Table 3. 2-Methylaminoethanol. Rotational Constants [1] (MHz) and Dipole Moments [2] * (D). ropt(1) = MP2/6-311+G(d,p), ropt(2) = MP2/6-311+G(df,pd). |
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Conf gG'T
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ropt(1) |
ropt(2) |
Expt [1,2]
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A
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11951
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11973
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12123.7430(6)
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B
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2691
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2722
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2653.8058(2)
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C
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2431
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2454
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2400.7362(2)
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|µa|
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2.49
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2.50
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2.272(8)
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|µb| |
1.53
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1.52
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1.336(20)
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|µc| |
0.87
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0.86
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0.808(18)
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|µtot| |
3.05
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3.05
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2.756(13)
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Conf g'GG
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A
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9200
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9159
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9155.314(2)
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B
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3091
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3150
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3076.3199(5)
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C
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2891
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2932
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2868.6381(4)
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|µa| |
2.83
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2.82
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2.610(11)
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|µb| |
1.39
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1.43
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1.132(11)
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|µc| |
0.17
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0.16
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0.331(34)
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|µtot| |
3.16
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3.17
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2.864(11)
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* Calculated by B3PW91/6-311+G(df,pd) method on MP2 ropt structures.
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[1] C.Calabrese,
A.Maris, L.Evangelisti, A.Piras, V.Parravicin, and S.Melandri,
Frontiers in Chemistry|www.frontiersin.org, Volume 6, Article 25 (2018).
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[2] R.E.Penn and L.W.Buxton, J.Mol.Spectrosc. 56,229(1975).
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S.Melandri, A.Maris, and C.Calabrese, Abstract WF15, 68th International Symposium on Molecular Spectroscopy, 2013.
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Dimethylamine |
Diethylamine
| Methylaminoethane
|
2-Dimethylaminoethanol
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Table of Contents |
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Molecules/Nitrogen |
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MAE.html |
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Last
Modified 18 April 2018 |
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