C9H11NO3











 


























 









Nitrogen


Nuclear Quadrupole Coupling Constants

in Tyrosine

 








 








 

 





Calculation of the 14N nuclear quadrupole coupling constant tensors in tyrosine was made here on ropt molecular structures given by MP2/6-311++G(d,p) [1] and B3P86/6-31G(3d,3p) optimization.

 








Calculated and experimental [1] nitrogen nqcc's are compared in Table 1.  Structure parameters are given here in Z-Matrix format.  Rotational constants are given in Table 2.

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.  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. 


 








 








   







Table 1.  14N nqcc's in Tyrosine (MHz).  Calculation was made on (1) MP2/6-311++G(d,p) and (2) B3P86/6-31G(3d,3p) ropt structures.
   









Calc (1)
Calc (2)
Expt [1]
   







Xaa


0.390
0.709(14)

Xbb


0.558
0.236(88)

Xcc

-
 0.947
 -
 0.945(88)

Xab

-
 1.258



Xac


2.190



Xbc


2.585


 







RMS


0.262 (42. %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 







Xxx


1.658



Xyy


2.588



Xzz

-
 4.247



ETA


0.219



 








 








 







 





Table 2.  Tyrosine. Rotational Constants (MHz).  ropt(1) = MP2/6-311++G(d,p), ropt(2) = B3P86/6-31G(3d,3p).

 




ropt(1) ropt(2)      Expt [1]

 



A
1549.1
 1529.6791(40)

B
  461.4
   463.94021(32)

C
  424.6
   425.76168(40)



 








 








[1] C.Pérez, S.Mata, C.Cabezas, J.C.López, and J.L.Alonso, J.Phys.Chem. A 119(16),3731(2015).

 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 2 Apr 2015