CH3C(=O)N(H)-C(H)CH3-C(=O)NH2




 








 








Nitrogen

Nuclear Quadrupole Coupling Constants


in N-Acetyl-Alaninamide


 


















Nitrogen nqcc's in C7eq and C5 conformers of N-acetyl-alaninamide 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 - 2.  Structure parameters are given in Z-matrix format in Table 3, rotational constants in Table 4.











C7eq

C5





































 








In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia tensor.  RMS is the root measn square difference between calculated and experimental nqcc's.  RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd)  model for calculation of the efg's/nqcc's.

 








 








   







Table 1.  14N nqcc's in C7eq N-Acetyl-Alaninamide (MHz).  Calculation was made on (1)  mPW1PW91/6-31G(3d,3p) and (2) mPW1PW91/cc-pVDZ optimized structures.  Atomic numbering is shown above.
   









Calc (1)
Calc (2)
Expt. [1]
 








Xaa N(7)
1.521
1.511
1.5731(33)

Xbb -
 0.896
 -
 0.917
 -
 0.9751(70)

Xcc -
 0.625
 -
 0.594
 -
 0.5979(70)

Xab
1.056
1.071



Xac -
 1.325
 -
 1.310



Xbc
2.642
2.657



 







RMS
0.057 (5.4 %)
0.049 (4.7 %)



RSD
0.030 (1.3 %)
 0.030 (1.3 %)


 







Xaa N(3)
0.168
0.102
0.1133(88)

Xbb
2.082
2.089
2.0961(76)

Xcc -
 2.250
 -
 2.191
 -
 2.2095(76)

Xab
0.315
0.322



Xac
2.125
2.139



Xbc -
 0.618
 -
 0.616












RMS
0.040 (2.7 %)
0.015 (1.0 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 








 








 








   







Table 2.  14N nqcc's in C5 N-Acetyl-Alaninamide (MHz).  Calculation was made on (1)  mPW1PW91/6-31G(3d,3p) and (2) mPW1PW91/cc-pVDZ optimized structures.  Atomic numbering is shown above.
   









Calc (1)
Calc (2)
Expt. [1]
 








Xaa N(7)
2.095
2.114
2.085(25)

Xbb
1.159
1.109
1.232(48)

Xcc -
 3.254
 -
 3.223
 -
 3.316(48)

Xab
0.598
0.579



Xac
0.415
0.370



Xbc -
 1.755
 -
 1.784



 







RMS
0.055 (2.5 %)
0.091 (4.1 %)



RSD
0.030 (1.3 %)
 0.030 (1.3 %)


 







Xaa N(3)
1.593
1.627
1.754(21)

Xbb
0.965
1.163
0.998(37)

Xcc -
 2.558
 -
 2.790
 -
 2.752(37

Xab -
 0.619
 -
 0.547



Xac -
 1.466
 -
 1.469



Xbc -
 2.206
 -
 2.053












RMS
0.147 (8.0 %)
0.122 (6.7 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)



 








 








 












Table 3. N-Acetyl-Alaninamide, mPW1PW91/6-31G(3d,3p) and mPW1PW91/cc-pVDZ optimized molecular structures (Å and degrees).  Atomic numbering is given in Fig. 1.









 C
 C,1,B1
 N,2,B2,1,A1
 H,3,B3,2,A2,1,D1,0
 H,3,B4,2,A3,1,D2,0
 O,2,B5,1,A4,3,D3,0
 N,1,B6,2,A5,6,D4,0
 C,7,B7,1,A6,2,D5,0
 O,8,B8,7,A7,1,D6,0
 H,7,B9,1,A8,2,D7,0
 C,8,B10,7,A9,1,D8,0
 H,11,B11,8,A10,7,D9,0
 H,11,B12,8,A11,7,D10,0
 H,11,B13,8,A12,7,D11,0
 H,1,B14,7,A13,8,D12,0
 C,1,B15,7,A14,8,D13,0
 H,16,B16,1,A15,7,D14,0
 H,16,B17,1,A16,7,D15,0
 H,16,B18,1,A17,7,D16,0




      _________ C7eq _________     
        ___________ C5  ___________              
   6-31(3d,3p)
    cc-pVDZ
    6-31(3d,3p)    cc-pVDZ




 B1=1.54133991
 B2=1.3504847
 B3=1.01352472
 B4=1.00609265
 B5=1.2158468
 B6=1.45682713
 B7=1.35145349
 B8=1.22586494
 B9=1.00638072
 B10=1.50798754
 B11=1.0908549
 B12=1.09077484
 B13=1.09085972
 B14=1.09423293
 B15=1.51464039
 B16=1.09189443
 B17=1.08960657
 B18=1.09166972
 A1=113.56395768
 A2=119.43127541
 A3=117.85012223
 A4=122.22244052
 A5=110.3291126
 A6=123.1582746
 A7=122.18613026
 A8=117.64013735
 A9=116.33354559
 A10=108.47582069
 A11=113.68576213
 A12=108.77638759
 A13=106.23467508
 A14=110.20620893
 A15=110.73157694
 A16=110.13032798
 A17=110.47371312
 D1=-9.98305474
 D2=-172.69055665
 D3=179.58320319
 D4=-108.94205182
 D5=-82.75038347
 D6=2.11332549
 D7=94.65701064
 D8=-177.47663757
 D9=122.18703553
 D10=0.63442858
 D11=-121.27833965
 D12=33.98119669
 D13=154.08113944
 D14=63.98048361
 D15=-177.97524045
 D16=-57.66720585
  B1=1.54237922
 B2=1.3534554
 B3=1.01912826
 B4=1.01118202
 B5=1.21841506
 B6=1.45850048
 B7=1.35470236
 B8=1.22864561
 B9=1.0108554
 B10=1.50860541
 B11=1.0978958
 B12=1.09737688
 B13=1.09833483
 B14=1.10065205
 B15=1.51462244
 B16=1.09883862
 B17=1.09685547
 B18=1.09846068
 A1=113.21889542
 A2=118.92868902
 A3=117.67463849
 A4=122.29628261
 A5=110.32351133
 A6=122.81554882
 A7=122.19286157
 A8=117.77550451
 A9=116.17039492
 A10=108.36054122
 A11=113.90393121
 A12=108.73684203
 A13=105.90773026
 A14=110.37097149
 A15=110.54106589
 A16=110.1450115
 A17=110.62600084
 D1=-11.30594096
 D2=-171.79352363
 D3=179.59319238
 D4=-107.46192743
 D5=-82.06693251
 D6=1.96323544
 D7=93.5866864
 D8=-177.67566378
 D9=124.42347501
 D10=2.6583047
 D11=-119.46308379
 D12=34.44367697
 D13=154.67307019
 D14=66.19665174
 D15=-176.03491241
 D16=-55.72032775
  B1=1.52587222
 B2=1.35250642
 B3=1.00385139
 B4=1.0054964
 B5=1.21759447
 B6=1.43953491
 B7=1.35359736
 B8=1.22084772
 B9=1.01009652
 B10=1.51023163
 B11=1.09077594
 B12=1.09090586
 B13=1.09089513
 B14=1.09633283
 B15=1.53138596
 B16=1.08999782
 B17=1.09190211
 B18=1.09217387
 A1=115.44229387
 A2=121.82937869
 A3=118.22194107
 A4=121.85511958
 A5=106.9332641
 A6=121.70682308
 A7=122.14949916
 A8=115.43786806
 A9=115.84978554
 A10=113.52957421
 A11=108.70142368
 A12=108.6512826
 A13=108.28406725
 A14=112.19960667
 A15=108.88157994
 A16=110.34616132
 A17=111.35481625
 D1=-10.24145238
 D2=-178.63868374
 D3=177.89416034
 D4=-16.09247542
 D5=-158.07533317
 D6=-2.94330961
 D7=14.03336496
 D8=177.20752411
 D9=-0.28348111
 D10=121.39211168
 D11=-122.03233539
 D12=-39.88763858
 D13=79.94963013
 D14=-59.20975083
 D15=60.52812251
 D16=-178.92621616
  B1=1.52846614
 B2=1.35461876
 B3=1.00844247
 B4=1.01056502
 B5=1.22056961
 B6=1.43967675
 B7=1.35819521
 B8=1.22271008
 B9=1.01531037
 B10=1.51130952
 B11=1.09737465
 B12=1.0975642
 B13=1.09884585
 B14=1.10370578
 B15=1.53106778
 B16=1.09724535
 B17=1.09910058
 B18=1.09936061
 A1=115.36668079
 A2=121.83472705
 A3=118.04144208
 A4=121.92854082
 A5=106.76980628
 A6=121.34013781
 A7=122.10773893
 A8=114.61203179
 A9=115.51573534
 A10=113.61545672
 A11=108.65998156
 A12=108.66669936
 A13=108.41990492
 A14=112.14748206
 A15=108.64722298
 A16=110.44135935
 A17=111.71445677
 D1=-10.32506838
 D2=-177.27657943
 D3=178.30419082
 D4=-10.7768944
 D5=-155.15125291
 D6=-6.1043399
 D7=10.6037143
 D8=174.08182087
 D9=6.20651782
 D10=128.26093653
 D11=-115.4776002
 D12=-37.44824413
 D13=82.07542424
 D14=-59.11952169
 D15=60.47094936
 D16=-178.69765853
 




 








  








 



Table 4. N-Acetyl-Alaninamide, mPW1PW91/6-31G(3d,3p), mPW1PW91/cc-pVDZ, and experimental rotational constants (MHz).







6-31G(3d,3p)
 cc-pVDZ
   Expt. [1]





     C7eq A
   2607.
   2591.
 2598.76659(80)

B
   1132.
   1134.
 1125.71115(18)

C
     917.
     919.
   914.49488(20)





     C5 A
   3082.
   3051.
 3100.286(32)

B
     959.
     966.
   955.11278(23)

C
     817.
     814.
   812.74871(20)


 








 








[1] C.Cabezas, M.Varela, V.Cortijo, A.Jiménez, I.Peña, A.M.Daly, J.C.López, C.Cativiela, and J.L.Alonso, PCCP 15,2580(2013).

 








 








N-Acetylglycinamide
 N-Acetylglycine Alaninamide
 Alanine

 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 4 April 2016