COOH-CH(NH2)-CH2-CONH2




















 





 





Nitrogen

Nuclear Quadrupole Coupling Constants

in Asparagine

 








 








 








Nitrogen nqcc's in asparagine were determined by Cabezas et al. [1].  

 








Calculation of the nqcc tensors was made here on molecular structures given by mPW1PW91/6-31G(3d,3p) and mPW1PW91/cc-pVDZ optimization.  Calculated and experimental nqcc's are compared in Tables 1 and 2.  Structure parameters are given in Z-matrix format in Table 3, rotational constants in Table 4.

 








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 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 nitrogen efg's/nqcc's.

 








 








   







Table 1.  14N(6) - amide - nqcc's in Asparagine (MHz).  Calculation was made on (1) mPW1PW91/6-31G(3d,3p) and (2) mPW1PW91/cc-pVDZ optimized structures.
   









Calc (1)
Calc (2)
Expt. [1]
   







Xaa -
 1.459
 -
 1.575
 -
 1.4649(63)

Xbb
1.503
1.610
1.5518(76)

Xcc -
 0.044
 -
 0.035
 -
 0.0870(76)

Xab -
 1.856
 -
 0.885



Xac
2.373
2.400



Xbc
1.007
0.873



 







RMS
0.038 (3.7 %)
0.078 (7.5 %)


RSD
0.030 (1.3 %)
0.030 (1.3 %)


 







Xxx
1.625
1.606



Xyy
2.012
2.009



Xzz -
 3.637
 -
 3.615



ETA
0.106
0.112



 








 








 







   







Table 2.  14N(9) - amine - nqcc's in Asparagine (MHz).  Calculation was made on (1) mPW1PW91/6-31G(3d,3p) and (2) mPW1PW91/cc-pVDZ optimized structures.
   









Calc (1)
Calc (2)
Expt. [1]
   







Xaa -
 2.084
 -
 2.341
 -
 2.0313(50)

Xbb
2.591
2.570
2.5720(57)

Xcc -
 0.507
 -
 0.229
 -
 0.5408(57)

Xab
0.094
0.074



Xac
2.765
2.586



Xbc -
 0.598
 -
 0.534



 







RMS
0.038 (2.2 %)
0.254 (15. %)


RSD
0.030 (1.3 %)
0.030 (1.3 %)


 







Xxx
1.431
1.375



Xyy
2.767
2.722



Xzz -
 4.191
 -
 4.097



ETA
0.318
0.326



 








 








 














Table 3.  Asparagine.  Optimized structure parameters, mPW1PW91/6-31G(3d,3p) and mPW1PW91/cc-pVDZ (Å and degrees).
 








 C
 C,1,B1
 C,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 O,1,B4,2,A3,3,D2,0
 N,1,B5,5,A4,2,D3,0
 H,6,B6,1,A5,5,D4,0
 H,6,B7,1,A6,5,D5,0
 N,3,B8,2,A7,1,D6,0
 H,9,B9,3,A8,2,D7,0
 H,9,B10,3,A9,2,D8,0
 O,4,B11,3,A10,2,D9,0
 O,4,B12,3,A11,2,D10,0
 H,13,B13,4,A12,3,D11,0
 H,3,B14,2,A13,1,D12,0
 H,2,B15,1,A14,5,D13,0
 H,2,B16,1,A15,5,D14,0







   6-31G(3d,3p)
    cc-pVDT


 B1=1.51475314
 B2=1.53500721
 B3=1.53717068
 B4=1.2223499
 B5=1.35302474
 B6=1.00787196
 B7=1.00737634
 B8=1.45999395
 B9=1.01860543
 B10=1.01085982
 B11=1.20564967
 B12=1.32185771
 B13=0.98804346
 B14=1.0947437
 B15=1.09037988
 B16=1.09088692
 A1=109.77175124
 A2=110.20550098
 A3=120.97942646
 A4=123.07480179
 A5=119.13893368
 A6=116.89592093
 A7=115.48791673
 A8=109.55850052
 A9=111.43634111
 A10=122.88406843
 A11=113.40970674
 A12=103.68951685
 A13=108.12347368
 A14=111.94654371
 A15=107.70105107
 D1=-66.8218858
 D2=-76.70650846
 D3=-178.63267546
 D4=161.44505129
 D5=9.36839735
 D6=57.27251815
 D7=-25.51052999
 D8=93.22267672
 D9=-37.42046057
 D10=143.49889332
 D11=-5.43176203
 D12=179.20061005
 D13=162.23080348
 D14=42.20738525
 B1=1.5161851
 B2=1.53467115
 B3=1.53895678
 B4=1.22532909
 B5=1.3560274
 B6=1.01333004
 B7=1.01303828
 B8=1.46074444
 B9=1.02561514
 B10=1.01711859
 B11=1.208893
 B12=1.32339334
 B13=0.99483808
 B14=1.10239598
 B15=1.09661474
 B16=1.0979569
 A1=109.5837353
 A2=110.21329436
 A3=121.12227224
 A4=123.22028336
 A5=118.18474617
 A6=116.26832121
 A7=115.79762268
 A8=108.53984533
 A9=111.00579933
 A10=123.07787633
 A11=112.90537783
 A12=102.72480126
 A13=108.30781239
 A14=111.9935966
 A15=107.8092016
 D1=-65.79917172
 D2=-73.71006166
 D3=-178.50406986
 D4=158.02425372
 D5=10.44525698
 D6=57.82011142
 D7=-28.05647717
 D8=88.66570601
 D9=-34.33765225
 D10=146.42054528
 D11=-6.62020622
 D12=179.90871991
 D13=165.32099128
 D14=45.35725641








 








 













Table 4. Asparagine:  mPW1PW91/6-31G(3d,3p), mPW1PW91/cc-pVDZ, and Experimental Rotational Constants (MHz).







6-31G(3d,3p) cc-pVDZ   Expt [1]






A
    2295.
    2293.
 2270.85145(85)

B
    1390.
    1399.
 1387.80238(41)

C
    1102.
    1102.
 1102.63540(41)







 








 








[1] C.Cabezas, M.Varela, I.Peña, S.Mata, J.C.López and J.L.Alonso, Chem.Commun. 48, 5934(2012).

 








 








N-Acetyl-Alaninamide






 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 6 April 2016