(CH2Cl)CH=C=CH2























 








Chlorine

Nuclear Quadrupole Coupling Constants


in skew-Chloromethylallene


 
(4-Chloro-1,2-butadiene)



 








 








The microwave spectrum of chloromethylallene was assigned by Karlsson et al. [1].  However, hyperfine structure due to the chlorine quadrupole interaction was not resolved.











Calculation of the chlorine nqcc tensor in 4-methylcyanoallene was made here on molecular structures given by MP2/6-311+G(3df,3pd) optimization, and on this same structure but with approximate equilibrium bond lengths.  These nqcc's are given in Tables 1 and 2.  Structure parameters are given in Z-matrix format in Table 3,  rotational 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.  ETA = (Xxx - Xyy)/Xzz.  Øz,CCl (degrees) is the angle between the z-principal axis and the C-Cl bond axis.

RSD is the residual standard deviation of calibration of the B1LYP/TZV(3df,2p) model for calculation of the efg's/nqcc's.

 








 








 








Table 1. 35Cl nqcc's in Chloromethylallene (MHz).  Calculation was made here on molecular structures given by (1) MP2/6-311+G(3df,3pd) optimization and (2) MP2/6-311+G(3df,3pd) optimization with approximate re bond lengths.
 










Calc (1)
Calc (2)
Expt
 








Xaa -
 28.41
 -
 28.56



Xbb
  2.53
  2.52



Xcc
25.88
26.04



Xab -
 47.64
 -
 47.74



Xac
26.62
24.56



Xbc
18.11
18.05












RSD
0.49 (1.1 %)
0.49 (1.1 %)












Xxx
35.36
35.43



Xyy
37.16
37.21



Xzz -
 72.52
 -
 72.64



ETA
0.0247
0.0244



Øz,CCl
0.27
0.28












   








 








 








Table 2. 37Cl nqcc's in Chloromethylallene (MHz).  Calculation was made here on molecular structures given by (1) MP2/6-311+G(3df,3pd) optimization and (2) MP2/6-311+G(3df,3pd) optimization with approximate re bond lengths.
 










Calc (1)
Calc (2)
Expt
 








Xaa -
 22.72
 -
 22.84



Xbb
  2.23
  2.24



Xcc
20.49
20.61



Xab -
 37.49
 -
 37.58



Xac
19.35
19.30



Xbc
14.13
14.08












RSD
0.44 (1.1 %)
0.44 (1.1 %)













 









 



Table 3.  Chloromethylallene.  MP2/6-311+G(3df,3pd) optimized structure parameters (Å and degrees).  Approximate re bond lengths are given in parentheses.








 C
 H,1,B1
 C,1,B2,2,A1
 C,3,B3,1,A2,2,D1,0
 H,4,B4,3,A3,1,D2,0
 C,4,B5,3,A4,1,D3,0
 Cl,6,B6,4,A5,3,D4,0
 H,6,B7,4,A6,3,D5,0
 H,6,B8,4,A7,3,D6,0
 H,1,B9,3,A8,4,D7,0














 B1=1.08168286
 B2=1.30791825      (1.3057)
 B3=1.30997599      (1.3077)
 B4=1.08385779
 B5=1.49243391      (1.4917)
 B6=1.78899767      (1.7936)
 B7=1.08656362
 B8=1.08523668
 B9=1.0815453
 A1=120.68748218
 A2=179.24320534
 A3=120.00618133
 A4=122.21553637
 A5=110.75512428
 A6=111.43333572
 A7=111.26795557
 A8=120.93308129
 D1=-93.63122645
 D2=-177.38853156
 D3=3.28244023
 D4=115.66014898
 D5=-126.58345575
 D6=-3.65760605
 D7=86.62390094






















 



Table 4.  Chloromethylallene, 35Cl species.  Rotational Constants (MHz).  Calc (1) = MP2/6-311+G(3df,3pd) optimization, Calc (2) =  MP2/6-311+G(3df,3pd) optimization with approximate re bond lengths.







Calc (1)
 Calc (2)
   Expt [1]






A 14995
 14983
 15484(12)

B   1633
   1633
   1606.07(1)

C   1578
   1578
   1557.55(1)


 








 








 








[1] F.Karlsson, M.Granberg, and R.Vestin, Acta Chem. Scand. A 31,379(1977).

 








 








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Molecules/Chlorine




 








 













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Last Modified 8 May 2014