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