CH3CH2CH2CN
























 








Nitrogen

Nuclear Quadrupole Coupling Constants


in t-1-Cyanopropane


 








 








 








Calculation of the nitrogen nqcc tensor in the trans conformer of 1-cyanopropane (aka trans butyronitrile) was made here on an approximate equilibrium molecular structure given by MP2/aug-cc-pVTZ optimization with empirically corrected equilibrium bond lengths. These are compared in Table 1 with the experimental nqcc's of Demaison and Dreizler [1].  Structure parameters are given in Table 2, rotational constants in Table 3, dipole moments and quartic centrifugal distortion constants in Table 4.

 








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 c-axis, these are perpendicular to the Cs plane of the molecule.  Ø (degrees) is the angle between its subscripted parameters. ETA = (Xxx - Xyy)/Xzz.

RMS is the root mean square difference between calculated and experimental nqcc's (percentage of average experimental nqcc).  RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's.

 








 








   






Table 1. Nitrogen nqcc's in t-1-Cyanopropane (MHz).
   









Calc.
Expt. [1]
   






14N Xaa - 3.426 - 3.405(45)


Xbb
1.358
1.341(50)


Xcc
2.068
2.064(39)


|Xab|
2.090
2.090(32) *

 







RMS
0.016 (0.71 %)




RSD
0.030 (1.3 %)



 







Xxx
2.143
2.130(48)  **


Xyy
2.068
2.064(39)


Xzz - 4.211 - 4.194(44)


ETA - 0.018 - 0.015(15)


Øz,a
20.57
20.68(29)


Øa,CN
20.93




Øz,CN
  0.36



 






   








* Calculated value, with an estimated uncertainity of 2*RMS.

** Calculated here using Kisiel's QDIAG.f program.

 









 

Table 2.  t-1-Cyanopropane.  Heavy atom molecular structure parameters (Å and degrees).  Complete structure is given here in Z-matrix format.
   



C(11)N 1.1561

C(1)C(11) 1.4600

C(1)C(11)N 178.39

 

C(1)C(2) 1.5285

C(2)C(3) 1.5198

C(11)C(1)C(2) 112.03

C(1)C(2)C(3) 110.95








 








 


Table 3.  t-1-Cyanopropane.  Rotational Constants (MHz).






Calc. ropt    Expt. [2]





A 23 868.9 23668.31931(143)

B   2 289.9   2268.146892(147)

C   2 173.3   2152.963946(168)


 








 








 




Table 4.  t-1-Cyanopropane.  Dipole Moments [3] and Quartic Centrifugal Distortion Constants [2].  Calc = B3LYP/cc-pVTZ.









Calc.
Expt. [2,3]







|µa| /D
4.04
3.597(59)

|µb| /D
1.07
0.984(15)

 




DJ /kHz
0.380
0.398674(69)

DJK /kHz -
 10.3
 -
 10.82631(92)

DK /kHz
237.
240.653(29)

d1 /Hz -
 43.3
 -
 46.637(42)

d2 /Hz -
 0.473
 -
 0.5901(59)








 








 








[1] J.Demaison and H.Dreizler, Z.Naturforsch. 37a,199(1982).

[2] G.Wlodarczak, L.Martinache, J.Demaison, K.-M.Marstokk, and H.Møllendal, J.Mol.Spectrosc. 127,178(1988).

[3] A.Belloche, R.T.Garrod, H.S.P.Müller, K.M.Menten, C.Comito, and P.Schilke, A & A 499,215(2009).

 








K.Vormann and H.Dreizler, Z.Naturforsch. 43a,338(1988):  Xaa = -3.440(4) MHz,  Xbb = 1.385(5) MHz,  Xcc = 2.056(5) MHz.

 








 








n-Butyl Cyanide, anti-anti 1-Cyanopropane, gauche

n-Butyl Cyanide, anti-gauche CH3CN


n-Butyl Cyanide, gauche-anti CH3CH2CN

 








 








Table of Contents




Molecules/Nitrogen




 








 













t1CNpropane.html






Last Modified 23 Aug 2010