Nuclear Quadrupole Coupling Constants

in gauche-3-Cyanopropene




Calculation of the nitrogen nqcc tensor was made here on a molecular structure given by MP2/aug-cc-pVTZ(G03) with ~re bond lenghts for C-C, C=C, and CN.  These calculated nqcc's are given  in Table 1.  Structure parameters are given in Table 2, rotational constants 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.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's.



Table 1.  Nitrogen nqcc's in gauche 3-Cyanopropene (MHz).  Calculation was made on the MP2/aug-cc-pVTZ(G03) optimized molecular structure with ~re bond lenghts for C-C, C=C, and CN.


14N Xaa - 2.714
Xbb 0.610
Xcc 2.104
|Xab| 2.694 *
|Xac| 0.146
|Xbc| 0.193
RSD 0.030 (1.3 %)
Xxx 2.016
Xyy 2.210
Xzz - 4.226
ETA 0.046
Øz,CN 0.31
* The algebraic sign of the product XabXacXbc is negative.
Table 2.  gauche 3-Cyanopropene.  Heavy atom structure parameters (Å and degrees).  MP2/aug-cc-pVTZ(G03) optimized molecular structure with ~re bond lenghts for C-C, C=C, and CN.  Complete structure is given here in Z.matrix format.

C(4)C(2) 1.3292
C(2)C(3) 1.5026
C(3)C(9) 1.4634
C(9)N 1.1560
C(4)C(2)C(3) 123.17
C(2)C(3)C(9) 111.49
C(3)C(9)N 178.98
C(4)C(2)C(3)C(9) 122.75
C(2)C(3)C(9)N   18.07



Table 3.  gauche 3-Cyanopropene.  Rotational Constants (MHz) and Dipole Moments (Debye).
Calc Expt [1]

A 19162.57 19707.9(1)
B   2660.32   2619.74(5)
C   2533.87   2497.43(5)
Calculation of the dipole moments was made at the B3PW91/6-311+G(df,pd) level of theory.
mua 3.61 3.50(5)
mub 1.81 1.70(2)
muc 0.18 0.19(4)
mutot 4.04

[1] E.Zeisberger and I.Botskor, J.Mol.Struct. 97,323(1983).
gauche-3-Chloropropene gauche-3-Bromopropene



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Last Modified 9 Oct 2009