(CH3)2N-CH2-COOH



 








 








Nitrogen

Nuclear Quadrupole Coupling Constants


in N,N-Dimethylglycine


 


















Nitrogen nqcc's in each of the following conformers of N,N-dimethylglycine were determined by Lesarri et al. [1].  Calculation of the nqcc tensors was made here on molecular structures given by B3P86 and mPW1PW91optimization in conjunction with 6-31G(3d,3p) and/or cc-pVDZ bases.  Calculated and experimental nqcc's are compared in Tables 1 - 3.  Rotational constants are given in Table 4.











Conformer 1

 Conformer 2 (CS)
Conformer 3


































 








In Tables 1 - 3, subscripts a,b,c refer to the principal axes of the inertia tensor, x,y,z to principal axes of the nqcc 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 Conformer 1 (MHz).  Calculation was made on (1)  B3P86/6-31G(3d,3p) and (2) mPW1PW91/6-31G(3d,3p) optimized structures.
   









Calc (1)
Calc (2)
Expt. [1]
 








Xaa
1.845
1.861
1.9637(12)

Xbb
0.637
0.645
0.5586(23)

Xcc -
 2.483
 -
 2.506
 -
 2.5223(23)

Xab
1.281
1.276



Xac
1.985
1.981



Xbc -
 3.042
 -
 2.506



 







RMS
0.085 (5.1 %)
0.078 (4.7 %)



RSD
0.030 (1.3 %)
 0.030 (1.3 %)


 







Xxx
2.477
2.487



Xyy
2.662
2.670



Xzz -
 5.140
 -
 5.157



 








 








 








   







Table 2.  14N nqcc's in Conformer 2 (MHz).  Calculation was made on (1)  B3P86/cc-pVDZ and (2) mPW1PW91/cc-pVDZ optimized structures.
   









Calc (1)
Calc (2)
Expt. [1]
 








Xaa
0.580
0.593
0.5689(16)

Xbb -
 3.336
 -
 3.360
 -
 3.3212(24)

Xcc
2.756
2.767
2.5723(24)

Xab
4.109
4.113



 







RMS
0.013 (0.57 %)
0.028 (1.3 %)



RSD
0.030 (1.3 %)
 0.030 (1.3 %)


 







Xxx
2.756
2.767



Xyy
3.174
3.180



Xzz -
 5.930
 -
 5.947



 








 








 








   







Table 3.  14N nqcc's in Conformer 3 (MHz).  Calculation was made on (1)  B3P86/6-31G(3d,3p) and (2) mPW1PW91/6-31G(3d,3p) optimized structures.
   









Calc (1)
Calc (2)
Expt. [1]
 








Xaa
2.692
2.687
2.6668(13)

Xbb
1.747
1.721
1.7194(18)

Xcc -
 4.439
 -
 4.408
 -
 4.3862(18)

Xab -
 0.652
 -
 0.667



Xac
1.472
1.490



Xbc
2.578
2.620
2.82(15)

 







RMS
0.037 (1.3 %)
0.017 (0.58 %)



RSD
0.030 (1.3 %)
 0.030 (1.3 %)


 







Xxx
2.646
2.655



Xyy
3.034
3.037



Xzz -
 5.680
 -
 5.692



 








 








  








 



Table 4. N,N-Dimethylglycine,   Rotational Constants (MHz).







    B3P86/
 mPW1PW91/







6-31G(3d,3p)
 6-31G(3d,3p)      Expt. [1]
Conformer 1 A
      5121.
      5125.
 5086.50998(55)

B
      1613.
      1614.
 1606.56158(115)

C
      1543.
      1544.
 1536.58238(114)







  cc-pVDZ
   cc-pVDZ
Conformer 2 A
      4735.
      4744.
 4714.17739(82)

B
      1696.
      1695.
 1691.6780(50)

C
      1681.
      1681.
 1678.0189(49)







6-31G(3d,3p) 6-31G(3d,3p)
Conformer 3
 A
      5290.
      5294.
 5256.19735(23)

B
      1633.
      1631.
 1625.134199(99)

C
      1389.
      1391.
 1382.871741(101)


 








 








[1] A.Lesarri, E.J.Cocinero, J.C.López, and J.L.Alonso, ChemPhysChem 6,1559(2005).

 








 








N-Acetylglycinamide
 N-Acetylglycine
(CH3)3N

 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 10 April 2016