2-CN-C4H3O





 














 






 








Nitrogen

Nuclear Quadrupole Coupling Constants


in 2-Cyanofuran


 


















Calculation of the nitrogen nqcc tensor in 2-cyanofuran was made here on molecular structures given by B3P86/6-31G(3d,3p) and MP2/6-311+G(3df,3pd) optimization, the latter with corrected CN bond length.  These calculated nqcc's are compared with experimental values in Table 1.  Structure parameters are given in Z-matrix format 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.  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 (percent 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 efg's/nqcc's.

 








 








   







Table 1.  14N nqcc's in 2-Cyanofuran (MHz).

 







Calculation was made on


the [a] B3P86/6-31G(3d,3p) opt structure.


the [b] MP2/6-311+G(3df,3pd) opt structure with corrected CN bond length.
   









Calc. [a]
Calc. [b]
Expt. [1]
   







Xaa -
 4.293
 -
 4.295
 -
 4.26(5) *

Xbb
2.795
2.779
2.61 *

Xcc
1.498
1.517
1.65 *

|Xab|
0.248
0.258



 







RMS
0.14 (4.9 %)
0.13 (4.4 %)



RSD
0.030 (1.3 %)
 0.030 (1.3 %)


 







Xxx
2.804
2.788



Xyy
1.498
1.517



Xzz -
 4.302
 -
 4.305



ETA -
 0.304
 -
 0.295



Øz,a
2.00
2.08



Øa,CN
1.88
1.93



Øz,CN
0.12
0.15



 








 








* Calculated here from experimental (Xbb + Xcc) = 4.26(5) and (Xbb - Xcc) = 0.96(7) MHz.

 



Table 2.  2-Cyanofuran.  Structure parameters (Å and degrees).  B3P86/6-31G(3d,3p) and MP2/6-311+G(3df,3pd) optimized structures.  For the latter, the corrected CN bond length is given in parentheses.
 





                     C
                     C,1,B1
                     C,2,B2,1,A1
                     C,3,B3,2,A2,1,D1,0
                     O,4,B4,3,A3,2,D2,0
                     H,1,B5,2,A4,3,D3,0
                     H,2,B6,1,A5,5,D4,0
                     H,3,B7,2,A6,1,D5,0
                     C,4,B8,3,A7,2,D6,0
                     N,9,B9,5,A8,4,D7,0







       B3P86
         MP2







 B1=1.36082214
 B2=1.42021218
 B3=1.36593844
 B4=1.36273904
 B5=1.07819794
 B6=1.07888308
 B7=1.07886648
 B8=1.40978587
 B9=1.15880519
 A1=106.05416365
 A2=105.99327351
 A3=110.34798327
 A4=133.29432683
 A5=126.51060183
 A6=128.19225833
 A7=131.90383228
 A8=150.9411162
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
  B1=1.3660828
 B2=1.41761691
 B3=1.37225929
 B4=1.35621267
 B5=1.07494057
 B6=1.07599401
 B7=1.07616573
 B8=1.41400637
 B9=1.17271317   (1.1584)
 A1=106.36867643
 A2=105.71889273
 A3=110.66721519
 A4=133.78167933
 A5=126.05880574
 A6=128.57418819
 A7=131.96132429
 A8=150.79187993
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=180.
 D6=180.
 D7=180.







 























Table 3.  2-Chlorothiophene.  Rotational Constants (MHz).
   



[a] B3P86/6-31G(3d,3p) opt structure.

[b] MP2/6-311+G(3df,3pd) opt structure with corrected CN bond length.
 





Calc [a] Calc [b]    Expt. [1]






A
   9285.
   9253.
 9220.106(20)

B
   2040.
   2038.
 2029.262(11)

C
   1673.
   1670.
 1662.640(9)



  








 








[1] L.Engelbrecht and D.H.Sutter, Z.Naturforsch. 31a,670(1976).

 








 








2-Cyanothiophene 2-Cyanopyrrole

 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 17 Dec 2015