CH2OH-CH(NH2)-C(=O)OH




 








 









 










Nitrogen


Nuclear Quadrupole Coupling Constants

in Serine


 








 








 








Seven conformers of serine were identified and their microwave spectra assigned by Blanco et al. [1].


Calculations of the 14N nqcc tensors in these conformers (shown below) were made on ropt  molecular structures given by B3LYP/cc-pVTZ optimization.  Calculated and experimental [1] nqcc's are compared in Tables 1 - 3.

 









Conformer Ia

Conformer IIa












































Conformer I'b

Conformer IIb

Conformer IIIbetab

























 









Conformer IIc

Conformer IIIbetac












































In Tables 1 - 3, subscropts a,b,c refer to the principal axes of the inertia tensor.  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 efg's/nqcc's.

 








 
   




Table 1.  14N nqcc's in Serine, conformers Ia and IIa (MHz).  Expt. is Ref [1].






   
    Conformer Ia     Conformer IIa


    Calc.  /  Expt.
    Calc.  /  Expt.

   




Xaa - 4.503  / - 4.3023(27)
- 0.524  / - 0.6066(55)


Xbb   2.841  /   2.82359(63)
  2.038  /   2.0723(82)


Xcc   1.662  /   1.4788(46)
- 1.513  / - 1.466(30)


Xab   0.222  /
  1.376  /


Xac - 0.492  /
  2.592  /


Xbc - 0.016  /
- 1.461  /


 




RMS
  0.157 (5.5 %)
0.058 (4.2 %)


RSD   0.030 (1.3 %)
0.030 (1.3 %)

 




 








 








   




Table 2.  14N nqcc's in Serine, conformer I'b, IIb, and IIIbetab (MHz).   Expt. is Ref [1].
   





Conformer I'b Conformer IIb Conformer IIIbetab


Calc. / Expt. Calc. / Expt.
Calc. / Expt.
   




Xaa - 1.420 / - 1.1343(35)
- 3.628 / - 3.4616(19)
- 0.566 / - 0.6733(67)

Xbb   2.606 /   2.5043(50)
  2.159 /   2.07974(93)
- 0.828 / - 0.456(16)

Xcc - 1.187 / - 1.3701(50)
  1.469 /   1.3819(47)
  1.394 /   1.129(16)

Xab   1.268 /
  1.629 /
  2.572 /

Xac - 2.976 /
  1.342 /
  1.607 /

Xbc   1.053 /
  0.007 /
- 2.534 /

 




RMS
0.145 (8.7 %)
0.118 (5.1 %)
0.271 (36.0 %)

RSD 0.030 (1.3 %) 0.030 (1.3 %) 0.030 (1.3 %)

 




 








 








   




Table 3.  14N nqcc's in Serine, conformers IIc and IIIbetac (MHz).  Expt. is Ref [1].





   
    Conformer IIc     Conformer IIIbetac


    Calc.  /  Expt.
    Calc.  /  Expt.

   




Xaa - 3.788  / - 3.6527(57)
- 1.085  / - 1.0486(55)


Xbb   2.041  /   2.06213(26)
- 0.647  /  - 0.5637(53)


Xcc   1.747  /   1.5906(50)
  1.731  /    1.612(21)


Xab - 1.863  /
- 3.522  /


Xac - 0.739  /
  0.794  /


Xbc   0.050  /
  1.499  /


 




RMS
  0.120 (4.9 %)
0.086 (8.0 %)


RSD   0.030 (1.3 %)
0.030 (1.3 %)

 




 









 








[1] S.Blanco, M.E.Sanz, J.C.López, and J.L.Alonso, PNAS 104,20183(2007).


 








 








Sarcosine
Paracetamol
Phenylglycinol
Tyrosine


Alanine








 









 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 7 April 2015