C(H)Cl=C(H)CCH
		Chlorine
	Nuclear Quadrupole Coupling Constants
		in t-1-Chlorobuten-3-yne
	Calculation of the chlorine nqcc's in t-1-chlorobuten-3-yne was made on an approximate equilibrium structure derived here by MP2/aug-cc-pVTZ optimization with empirically corrected bond lengths.  These nqcc's are compared with the available experimental values [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; 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 molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	RSD is the calibration residual standard deviation for the B1LYP/TZV(3df,2p) model for calculation of the chlorine nqcc's, which may be taken as an estimate of the uncertainty in the calculated coupling constants.
	Table 1. Chlorine nqcc's in t-1-Chlorobuten-3-yne (MHz).     Calc. Expt. [1]     35Cl Xaa - 63.55 - 63.6(4) Xbb 33.45 Xcc 30.10 |Xab| 27.34   RSD 0.49 (1.1 %)   Xxx 40.64 Xyy 30.10 Xzz - 70.74 ETA - 0.149 Øz,a 14.72 Øa,CCl 14.53 Øz,CCl   0.19     37Cl Xaa - 50.09 - 51.0(4) Xbb 26.36 Xcc 23.73 |Xab| 21.57   RSD 0.44 (1.1 %)
	Table 2.  t-1-Chlorobuten-3-yne   Heavy atom structure parameters (Å and degrees).  Complete structure is given here in Z-matix format.   Parameter  reapprox C(1)Cl 1.7167 C(1)=C(2) 1.3366 C(2)C(6) 1.4220 C(6)C(7) 1.2069 C(2)C(1)Cl 122.22 C(1)C(2)C(6) 120.48
	Table 3.  t-1-Chlorobuten-3-yne  Rotational Constants (MHz).   Calc is on the reapprox molecular structure.     Calc.   Expt. [1] A 48436.8 48604(41) B   1514.9   1509.612(2) C   1469.0   1463.459(2)
	[1] F.Karlsson and R.Vestin, Acta Chem. Scand. 27,3033(1973).
	CH2=C=C=CHCl		2-Chlorobuten-3-yne		4-Chlorobuten-3-yne
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	Molecules/Chlorine
						t1Clbuten3yne.html
						Last Modified 29 Nov 2011