Nuclear Quadrupole Coupling Constants

in Cyclopropenylidene-d1


Calcuation was made of the deuterium nqcc's in cyclopropenylidene-d1 on a structure given by MP2/aug-cc-pVTZ(G03) optimization.  These are compared with the experimental values of Bell et al. [1] in Table 1.  Structure parameters are given in Table 2, rotational constants in Table 3.



In Table 1, the subscripts a,b,c refer to the principal axes of the inertia tensor, the subscripts x,y,z to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia c-axis.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
RMS is the root mean square difference betwenn calculated and experimental diagonal nqcc's.  RSD is the residual standard deviation of calibration of the B3LYP/6-31G(df,3p) model for calculation of the nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's.



Table 1.  Deuterium nqcc's in cyclopropenylidene-d1 (kHz).  Calculation was made on the structure given by MP2/aug-cc-pVTZ(G03) optimization.

Expt. [1]

2H Xaa 188.6 180.9(13)
Xbb - 99.7 - 93.4
Xcc - 88.9 - 87.5(18)
|Xab|   45.6
RMS 5.8 (4.8 %)
RSD 1.1 (0.9 %)
Xxx - 106.7
Xyy - 88.9
Xzz 195.6
ETA - 0.091
Øz,b   8.78
Øb,CD   8.78
Øz,CD   0.00


Table 2.  Cyclopropenylidene.  MP2/aug-cc-pVTZ(G03) ropt molecular structure parameters (Å and degrees).
Point Group: C2V
   Click on image to enlarge.
C(1)C(2,3) 1.4210
C(2)C(3) 1.3307
C(3)C(1)C(2)   55.84
C(2)H(4) 1.0759
C(3)C(2)H(4) 150.12

Table 2.  Cyclopropenylidene.  Rotational Constants (MHz).  Normal Species.
   ropt     Expt.
A 35 211.9
B 32 041.0
C 16 775.9

[1] M.B.Bell, J.K.G.Watson, P.A.Feldman, H.E.Matthews, S.C.Madden, and W.M.Irvive, Chem.Phys.Lett. 136,588(1987).




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Last Modified 2 March 2008