H2C=CCH3CN PDF













 








Nitrogen

Nuclear Quadrupole Coupling Constants


in Methacrylonitrile


 








 








 








In Table 1, 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 the nitrogen nqcc's.

 








Subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.

 








 








   






Table 1. Nitrogen nqcc's in Methacrylonitrile (MHz).  Calculation was made on the near-re structure of Lessari et al. [1].
   









Calc.
Expt. [1]
   






14N Xaa - 4.235 - 4.2327(88)


Xbb
2.126
2.169(17)


Xcc
2.109
2.063(17)


|Xab|
0.465



 







RMS
0.036 (1.3 %)



RSD
0.030 (1.3 %)



 







Xxx
2.160
2.203 *


Xyy
2.109
2.063


Xzz - 4.269 - 4.266


ETA - 0.012 - 0.032


Øz,a
4.16
4.13


Øa,CN
4.91
4.91


Øz,CN
0.8
0.8

 







 








* Calculated here from the diagonal experimental nqcc's and the calculated off-diagonal nqcc.

 








 

Table 2.  Molecular structure parameters, near-re [1] (Å and degrees).
Hc and Ht are with respect to CN.
Hs is the in-plane methyl H, Ha are the out-of-plane methyl H's.
 


C=C 1.339

C-CN 1.438
Z-Matrix CN 1.158

C-CH3 1.500

CHc 1.080

CHt 1.081

CHs 1.088

CHa 1.090

C=C-CN 119.2

C=C-CH3 124.4

C=CHc 121.6

C=CHt 120.3

C-CHs 110.2

C-CHa 110.5

HaC-C=C 120.4

C-CN 178.3


 








 








[1] A.G.Lesarri, J.Cosléou, X.Li, G.Wlodarczak, and J.Demaison, J.Mol.Spectrosc. 172,520(1995).

 








J.C.López, J.Demaison, A.Gomez, and J.L.Alonso, J.Mol.Spectrosc. 141,317(1990).

C.L.Norris and W.H.Flygare, J.Mol.Spectrosc. 40,40(1971).  Xaa = -4.18(4) and Xbb = 2.03(15) MHz.

 








 








c-Crotononitrile t-Crotononitrile H2C=CHCN

 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 10 Aug 2004