C5H5-CN
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in 1-Cyano-1,3-cyclopentadiene
	The microwave spectrum of 1-cyano-1,3-cyclopentadiene has been investigated by Ford and Seitzman [1].  Rotational constants and dipole moments were determined.
	The 14N nqcc tensor was calculated here on a molecular structure given by MP2/6-311+G(3df,3pd) optimization with approximate equilibrium C-CN bond lengths.  These calculated nqcc's are given in Table 1, structure parameters in Table 2, rotational constants and dipole moments in Table 3.
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	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.  ETA = (Xxx - Xyy)/Xzz.  Ø (degrees) is the angle between its subscripted parameters.
	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. Nitrogen nqcc's in 1-Cyano-1,3-cyclopentadiene (MHz).     Calc. Expt.     14N Xaa - 4.166 Xbb 2.354 Xcc 1.812 Xab - 0.200   RSD 0.030 (1.3 %)   Xxx 2.360 Xyy 1.812 Xzz - 4.172 ETA 0.132 Øz,a 1.76 Øa,CN 2.25 Øz,CN 0.49
	Table 2.  1-Cyano-1,3-cyclopentadiene.  Molecular structure parameters (Å and degrees).       MP2/6-311+G(3df,3pd) opt structure with approximate equilibrium bond lengths given in parentheses.    C  H,1,B1  H,1,B2,2,A1  C,1,B3,3,A2,2,D1,0  H,4,B4,1,A3,3,D2,0  C,4,B5,1,A4,3,D3,0  H,6,B6,4,A5,1,D4,0  C,1,B7,4,A6,6,D5,0  C,8,B8,1,A7,4,D6,0  H,9,B9,8,A8,1,D7,0  C,8,B10,1,A9,4,D8,0  N,11,B11,9,A10,8,D9,0    B1=1.09370892  B2=1.09370892  B3=1.49296096  B4=1.07946805  B5=1.35370681  B6=1.07961602  B7=1.50045609  B8=1.3599325  B9=1.08016087  B10=1.41547184      (1.4185)  B11=1.17418723      (1.1594)  A1=107.06526942  A2=112.27749818  A3=123.89902261  A4=109.5152913  A5=126.10803111  A6=102.95448667  A7=109.26832095  A8=125.25960199  A9=123.72727626  A10=155.4285791  D1=-123.66243328  D2=60.3500046  D3=-119.6499954  D4=180.  D5=0.  D6=0.  D7=180.  D8=180.  D9=180.
	Table 3.  1-Cyano-1,3-cyclopentadiene  Rotational Constants (MHz) and Dipole Moments * (D).  Calc Expt. [1]  A 8407.2   8356  B 1910.5   1904.24  C 1571.8   1565.36 |µa|  4.69    4.25 |µb|  0.34 < 0.3 * B3PW91/6-311+G(df,pd) calculation on the MP2 structure.
	[1] R.G.Ford and H.A.Seitzman, J.Mol.Spectrosc. 69,326(1978).
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	Molecules/Nitrogen
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						Last Modified 30 Dec 2013