Morpholine

OC4H8N-H

 
 
 


Nitrogen and Deuterium


Nuclear Quadrupole Coupling Constants

in Morpholine (chair, eq and ax)


 







 

 


 




Calculation of the nitrogen nqcc's in equatorial and axial morpholine (chair) was made here on molecular structures given by MP2/6-311+G(2d,2p) optimization and, for the equatorial conformer, on the effective structure of Indris, et al. [1].   These are compared with the experimental nqcc's for equatorial morpholine [1] in Tables 1 - 3.  Calculated nqcc's for the axial conformer are given in Tables 4 and 5.  MP2/6-311+G(2d,2p) structure parameters are shown in Table 6, rotational constants in Table 7.
 
In Tables 1 - 4, 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 y-axis is chosen coincident with the inertia b-axis, these are perpendicular to the molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
 
RMS is the root mean square difference between calculated and experimental nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation of the models for calculation of nitrogen and deuterium nqcc's.
 
 
   







Table 1.  Nitrogen nqcc's in Morpholine, equatorial (MHz).  Calculation was made on the MP2/6-311+G(2d,2p) optimized structure.
   










Calc.
Expt. [2]
   






14N Xaa 2.210 2.1491(24)
Xbb 2.788 2.7966(25)
Xcc - 4.998 - 4.9457(24)
|Xac| 0.735
 
RMS 0.046 (1.4 %)  
RSD 0.030 (1.3 %)
 
Xxx 2.284
Xyy 2.788
  Xzz - 5.072
  ETA 0.099
Øz,a 84.24
Øa,NH 15.44
Øz,NH 68.79
Øz,NC 72.33
 
 
 
   







Table 2.  Nitrogen and Deuterium nqcc's in N-Deutero-Morpholine, equatorial.  Calculation was made on the MP2/6-311+G(2d,2p) optimized structure.
   










Calc.
Expt. [2]
   






14N (MHz) Xaa 2.210 2.166(6)
Xbb 2.788 2.787(4)
Xcc - 4.998 - 4.953(6)
|Xac| 0.732
 
RMS 0.037 (1.1 %)  
RSD 0.030 (1.3 %)
 
 2H (kHz) Xaa 221.9 220(10)
Xbb - 102.2 - 108(6)
  Xcc - 119.7 - 112(11)
  |Xac|   96.1
 
RMS 5.7 (3.9 %)
RSD 1.1 (0.86 %)
 
  Xxx - 144.9
Xyy - 102.2
Xzz 247.1
ETA - 0.173
Øz,a 14.68
Øa,ND 15.47
Øz,ND   0.79
 
 
 
   







Table 3.  Nitrogen nqcc's in Morpholine, equatorial (MHz).  Calculation was made on the ro structure [1].
   










Calc.
Expt. [2]
   






14N Xaa 2.279 2.1491(24)
Xbb 2.746 2.7966(25)
Xcc - 5.025 - 4.9457(24)
|Xac| 0.364
 
RMS 0.092 (2.8 %)  
RSD 0.030 (1.3 %)
 
Xxx 2.297
Xyy 2.746
  Xzz - 5.043
  ETA 0.089
Øz,a 92.85
Øa,NH 18.61
Øz,NH 68.55
Øz,NC 70.79
 
 
 
   







Table 4.  Nitrogen nqcc's in Morpholine, axial (MHz).  Calculation was made on the MP2/6-311+G(2d,2p) optimized structure.
   










Calc.
Expt.
   






14N Xaa - 3.550
Xbb 2.776
Xcc 0.774
|Xac| 0.656
 
RSD 0.030 (1.3 %)
 
Xxx 2.303
Xyy 2.776
  Xzz - 5.080
  ETA 0.093
Øz,a 152.93
Øa,NH   83.70
Øz,NH   69.22
Øz,NC   70.94
 
 
 
   







Table 5.  Nitrogen and Deuterium nqcc's in N-Deutero-Morpholine, axial.  Calculation was made on the MP2/6-311+G(2d,2p) optimized structure.
   










Calc.
Expt.
   






14N (MHz) Xaa - 3.419
Xbb 2.776
Xcc 0.642
|Xac| 3.083
 
RSD 0.030 (1.3 %)
 
 2H (kHz) Xaa - 134.2
Xbb - 100.1
  Xcc 234.2
  |Xac|   57.0
 
RSD 1.1 (0.86 %)
 
  Xxx - 142.8
Xyy - 100.1
Xzz 234.2
ETA - 0.176
Øz,a 81.40
Øa,ND 82.46
Øz,ND   1.06
 
 
 
Energy:  For the MP2/6-311+G(2d,2p) optimized structures, Eeq < Eax by 1.04, 0.82, and 0.76 kcal/mol respectively at the MP2/6-311+G(2d,2p), B3PW91/6-311+G(df,pd), and B3LYP/6-31G(df,3p) levels of theory.
 
 
 
Table 6. Molecular structure parameters, MP2/6-311+G(2d,2p) ropt (Å and degrees).
 
Equatorial Axial
Equatorial

C(1)N 1.4639 1.4661
NH 1.0102 1.0134
C(1)C(2) 1.5162 1.5202
C(2)O(3) 1.4266 1.4264
C(1)H(8) 1.0883 1.0888
C(1)H(9) 1.0970 1.0899
Axial C(2)H(10) 1.0937 1.0968

C(2)H(11) 1.0858 1.0869
C(5)NC(1) 109.89 109.97
NC(1)C(2) 108.14 112.67
C(1)C(2)O(3) 110.86 110.88
C(2)O(3)C(4) 110.08 110.26
NC(1)H(8) 109.26 109.12
NC(1)H(9) 112.50 107.64
Dihedral angles? C(1)C(2)H(10) 109.34 109.83
See Z-Matrix. C(1)C(2)H(11) 111.18 111.60


 
 
Table 7.  Morpholine.  Rotational Constants (MHz).  Normal Species.
 
  eq ropt eq Expt. [1] ax ropt  ax Expt.
A 4952.4 4924.9875(53) 4912.4
B 4651.0 4625.1166(53) 4608.0
C 2702.0 2684.2359(54) 2692.4
 
 
[1] O.Indris, W.Stahl, and U.Kretschmer, J.Mol.Spectrosc. 190,372(1998).

[2] J.-U.Grabow, H.Ehrlichmann, H.Dreizler, Z.Naturforsch. 44a,833(1989).

 







 

Piperidine Pyridine Pyrrolidine Pyrrole

Dimethylamine
 

 








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Molecules/Deuterium

 













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Last Modified 21 Feb 2006