CH2CH2CHCN



 









Chlorine


Nuclear Quadrupole Coupling Constants


in Cyclopropyl Cyanide


 







 
 
Calculation of the nitrogen nqcc's in cyclopropyl cyanide was made on an ropt structure obtained by MP2/6-311+G(2d,p) optimization (see below).  These are compared with the experimental nqcc's [1] 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, subscripts x,y,z to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia b-axis, these are perpendicular to the molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  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 is the calibration residual standard deviation for the B3PW91/6-311+(df,pd) model for calculation of the nitrogen nqcc's. 

 







 
 
   







Table 1. Nitrogen nqcc's in cyclic CH2CH2CHCN (MHz).  Calculation was made on the MP2/6-311+G(d,p) ropt structure.
   










Calc.
Expt. [1]
   






14N Xaa - 3.440 - 3.4536(35)
Xbb 1.678 1.7468(51)
Xcc 1.762 1.7068(51)
|Xac| 2.017
 
RMS 0.051 (2.2 %)
RSD 0.030 (1.3 %)
 
Xxx 2.452
Xyy 1.678
Xzz - 4.131
ETA - 0.187
Øz,a 18.89
Øa,CN 18.69
Øz,CN   0.20
 

 
 
Table 2.  Cyclopropyl Cyanide.  Molecular structure parameters, ropt (Å and degrees).
ropt = MP2/6-311+G(2d,p) optimization with corrected MP2/6-311+G(d,p) CN bond length [2].
 
Z-Matrix CN 1.1574
C(1)C 1.4378
C(1)C(2,3) 1.5175 *
C(2)C(3) 1.5001 *
CHs 1.0825
CHc 1.0818
CHt 1.0818
C(1)CN 179.67
CC(1)Hs 114.77
C(1)C(3)Hc 116.60
C(2)C(3)Hc 117.82
C(1)C(3)Ht 116.43
C(2)C(3)Ht 118.46
HcCHt 115.77
 
* The substitution structure of the ring was determined by Pearson et al. [3].  They find C(1)C(2,3) = 1.528(5) Å and C(2)C(3) = 1.500(2) Å.
 
 
Table 3.  Cyclopropyl Cyanide.  Rotational constants, ropt (MHz).
   Calc.    Expt. [1]
A 15 863.8 15 786.270(20)
B   3 467.1   3 465.107(4)
C   3 287.8   3 286.241(4)
 
 

[1] O.Böttcher, N.Heineking, and D.H.Sutter, Z.Naturforsch. 44a,655(1989).
[2] J.Demaison, J.Coslèou, R.Bocquet, and A.G.Lesarri, J.Mol. Spectrosc. 167,400(1994).
[3] R.Pearson Jr., A.Chopin, and V.Laurie, J.Chem.Phys. 62,4859(1975).
 
Also ...
R.D.Brown, P.D.Godfrey, and A.L.Ottrey, J.Mol.Spectrosc. 81,303(1980).  Xaa = -3.453(11) MHz and Xbb = 1.759(16) MHz.
 

 








CH2CH2CCl2 CH2CH2CHCl (Chloromethyl)cyclopropane
3-Cyanocyclopropene
 

 








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Last Modified 2 June 2006