CH3CH2-C(=O)N(CH3)2
























 





 








Nitrogen


Nuclear Quadrupole Coupling Constants

in N,N-Dimethylpropionamide

 








 








 








14N nqcc's in N,N-dimethylpropionamide were determined by Kannengießer [1].  Calculation was made here of the 14N nqcc tensor on ropt molecular structures derived by MP2/6-311++G(d,p) and HF/6-311++G(d,p) optimizations (assuming Cs symmetry).  These are compared with the experimental nqcc's in Table 1.  Structure parameters are given in Z-matrix format in Table 2.  Rotational constants are compared in Table 3.

 








In Table 1, 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 are 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 N,N-Dimethylpropionamide (MHz).  Calculation was made on the (1) MP2/6-311++G(d,p) and (2) HF/6-311++G(d,p) ropt structures.













Calc (1)

Calc (2)

Expt [1]

 








Xaa
2.119

2.108

2.0997(15)


Xbb - Xcc
7.137

7.226

7.2533(31)


Xbb
2.509

2.559

2.5768(34) *


Xcc -
4.628
-
4.667
-
4.6765(34) *


|Xab|
0.008

0.044




 








RMS

0.049 (1.6 %)

0.013 (0.41 %)




RSD

0.030 (1.3 %)

0.030 (1.3 %)













Xxx
2.119

2.104




Xyy
2.509

2.564




Xcc -
4.628
-
4.667




ETA
0.0841

0.0985













 








* Calculated here from expermental Xaa and Xbb - Xcc

 







 
 


Table 2.  N,N-Dimethylpropionamide.  MP2/6-311++G(d,p) and HF/6-311++G(d,p) ropt structure parameters.  (Å and degrees).
 




 O
 C,1,B1
 C,2,B2,1,A1
 N,2,B3,1,A2,3,D1,0
 C,4,B4,2,A3,1,D2,0
 C,4,B5,2,A4,1,D3,0
 H,3,B6,2,A5,1,D4,0
 H,3,B7,2,A6,1,D5,0
 H,5,B8,4,A7,2,D6,0
 H,5,B9,4,A8,2,D7,0
 H,5,B10,4,A9,2,D8,0
 H,6,B11,4,A10,2,D9,0
 H,6,B12,4,A11,2,D10,0
 H,6,B13,4,A12,2,D11,0
 C,3,B14,2,A13,1,D12,0
 H,15,B15,3,A14,2,D13,0
 H,15,B16,3,A15,2,D14,0
 H,15,B17,3,A16,2,D15,0






MP2/6-311++G(d,p)
HF/6-311++G(d,p)





 B1=1.22929032
 B2=1.52773775
 B3=1.3746377
 B4=1.45068827
 B5=1.45343623
 B6=1.09635083
 B7=1.09635083
 B8=1.09707619
 B9=1.08727236
 B10=1.09707619
 B11=1.09628005
 B12=1.08865167
 B13=1.09628005
 B14=1.52549856
 B15=1.09151493
 B16=1.09382117
 B17=1.09151493
 A1=121.00536422
 A2=121.96153281
 A3=125.54876096
 A4=119.50770276
 A5=109.11929588
 A6=109.11929588
 A7=110.14915416
 A8=111.41345752
 A9=110.14915416
 A10=110.16310206
 A11=108.7461245
 A12=110.16310206
 A13=111.49158569
 A14=110.72671068
 A15=110.10180536
 A16=110.72671068
 D1=180.
 D2=180.
 D3=0.
 D4=-121.91694883
 D5=121.91694883
 D6=120.37408277
 D7=0.
 D8=-120.37408277
 D9=120.07084542
 D10=0.
 D11=-120.07084542
 D12=0.
 D13=59.57998281
 D14=180.
 D15=-59.57998281
 B1=1.20004084
 B2=1.52412575
 B3=1.36070431
 B4=1.44653621
 B5=1.45016217
 B6=1.0867559
 B7=1.0867559
 B8=1.08740159
 B9=1.0769886
 B10=1.08740159
 B11=1.08743372
 B12=1.07658193
 B13=1.08743372
 B14=1.52406577
 B15=1.08309636
 B16=1.08622671
 B17=1.08309636
 A1=120.39748498
 A2=121.79606201
 A3=125.72639619
 A4=119.66526697
 A5=108.82516049
 A6=108.82516049
 A7=110.27677349
 A8=112.06486004
 A9=110.27677349
 A10=110.24735345
 A11=109.68457999
 A12=110.24735345
 A13=112.49469695
 A14=111.14157114
 A15=109.72415869
 A16=111.14157114
 D1=180.
 D2=180.
 D3=0.
 D4=-122.18370409
 D5=122.18370409
 D6=120.43039242
 D7=0.
 D8=-120.43039242
 D9=120.24786408
 D10=0.
 D11=-120.24786408
 D12=0.
 D13=59.90056872
 D14=180.
 D15=-59.90056872








 














Table 3.  N,N-Dimethylpropionamide.  MP2/6-311++G(d,p) and HF/6-311++G(d.p) ropt and Experimental Rotational Constants (MHz). 







MP2
HF
  Expt [1]






A
4693. 4800.
4691.96187(43)

B
1813. 1816.
1826.88254(22)

C
1352. 1362.
1358.78256(17)








[2] Raphaela Kannengießer, "Structures and Dynamics of Formamides, Acetamides, and Propionamides" Dissertation, RWTH Aachen University, Institute of Physical Chemistry, 2017.

 









 








N,N-Dimethylformamide
N,N-Dimethylacetamide

 








 









Table of Contents





Molecules/Nitrogen




 








 













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Last Modified 15 Jan 2018