(CH3CH2)3N
 

 








Nitrogen


Nuclear Quadrupole Coupling Constants

in Triethylamine


 







 
 
Nitrogen nqcc's in the minimum energy C3 conformer of triethylamine were determined by Nguyen et al. [1].  
 
Calculation of the 14N nqcc tensors was made here on molecular structures derived by MP2/6-311+G(d,p) and MP2/6-311+G(df,pd) optimizations (Note: Optimizations were undertaken using the NoSymm keyword.  The results were very near C3 symmetry and were, therefore, symmetrized to C3.  B3PW91/6-311+G(df,pd) electric field gradients were calculated on the symmetrized structures.).  Calculated and experimental nqcc's are compared in Table 1.  Structure parameters are given in Table 2, rotational constants in Table 3.
 
 
   







Table 1.  14N nqcc's in Triethylamine (MHz).  Calculation was made on the symmetrized (1) MP2/6-311+G(d,p) and (2) MP2/6-311+G(df,pd) optimized molecular structures.  Atomic numbering is shown below.
   







Species
Parameter

Calc. (1) Calc. (2)
Expt. [1]
   






Normal Xcc - 5.253 - 5.244 - 5.2444(7)
 
13C(3) Xcc - 5.253 - 5.243 - 5.2660(40)
Xbb - Xaa 0.000 0.000
|Xac| 0.029 0.028
 
13C(4) Xcc - 5.253 - 5.243 - 5.947(98)
Xbb - Xaa 0.000 0.000 - 0.257(19)
|Xac| 0.048 0.048
 
 
 
Table 2.  Triethylamine.  Selected structure parameters (Å and degrees).  Complete structures are given here in Z-matrix format.
 
ropt (1) = MP2/6-311+G(d,p) optimization, C3
ropt (2) = MP2/6-311+G(df,pd) optimization, C3
 
ropt (1) ropt (2)
NC(3) 1.4660 1.4598
C(3)NC(10) 110.59 110.71
C(3)C(4) 1.5256 1.5209
NC(3)C(4) 112.48 112.57
XNC(3)C(4) - 39.17 - 39.20
X is dummy atom
 
 
Table 3.  Triethylamine.  Rotational constants (GHz).
 
ropt (1) = MP2/6-311+G(d,p) optimization, C3
ropt (2) = MP2/6-311+G(df,pd) optimization, C3
 
Species Calc. ropt (1) Calc. ropt (2)    Expt. [1]
Normal A 2.3199 2.3351 2.314873978(11)
B 2.3199 2.3351 2.314873978(11)
C 1.3260 1.3349        ---------
 
13C(2) A 2.3179 2.3331 2.31293315(34)
B 2.2976 2.3127 2.29283301(33)
C 1.3193 1.3282 1.32681(96)
 
13C(3) A 2.3181 2.3333 2.31302815(28)
B 2.2560 2.2708 2.25126785(40)
C 1.3054 1.3142 1.32989(18)
 
 
 
[1] H.V.L.Nguyen, R.Kannengiesser, and W.Stahl, PCCP 14,11753(2012)

 








 







NH3 CH3NH2 CH3CH2NH2 Diethylamine
Dimethylamine Trimethylamine Quinuclidine NF3
 

 








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Molecules/Nitrogen
 

 













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Last Modified 16 July 2012