CH2CH2NH			PDF
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Ethylenimine
	Nitrogen nqcc's in ethylenimine were first determined in 1968 by Kemp and Flygare [1] and later, with improved resolution, by Thorwirth et al. [2,3].
	Calculation was made here of the nqcc's on the B3LYP/6-31G(3d,3p) optimized molecular structure.  These are compared with the experimental nqcc's [2] in Table 1.  Structure parameters are given in Table 2, atomic coordinates in Table 3, and rotational constants in Table 4.
	In Table 1, RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the nitrogen nqcc's.
	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 x-axis is chosen coincident with the inertia a-axis, these are perpendicular to the molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	Table 1. Nitrogen nqcc's in Ethylenimine (MHz).  Calculation was made on the B3LYP/6-31G(3d,3p) optimized molecular structure.     Calc. Expt. [2]     14N Xaa 0.692 0.68483 Xbb 2.178 2.17235(95) Xcc - 2.870 - 2.85718(88) |Xbc| 2.273   RMS 0.009 (0.47 %) RSD 0.030 (1.3 %)   Xxx 0.692 0.68483 Xyy 3.050 3.047 * Xzz - 3.742 - 3.732 ETA 0.630 0.633 Øz,a 21.00 21.05 Øa,NH 27.24 27.24 Øz,NH 48.24 48.29 Øz,bi **   8.28   8.31
	* Calculated here from the diagonal experimental nqcc's and the calculated off-diagonal nqcc.
	** Angle between the z-axis and the bisector ('bi') of the angle the NH bond axis makes with the CNC plane.
	Table 2.  Molecular structure parameters, ropt (Å and degrees). Hc and Ht are cis and trans with respect to the imine hydrogen.   NH 1.0169 NC 1.4730 Z-Matrix CC 1.4807 CHc 1.0863 CHt 1.0853 CNC   60.35 CNH 109.79 NCHc 118.69 NCHt 114.69 HcCHt 114.63
	Table 3. Atomic coordinates ropt. (More figures are shown than are significant.)   a (Å)   b (Å)   c (Å) N 0.0 0.840294 - 0.083125 H 0.0 1.305816 0.820991 C ± 0.740365 - 0.429721 0.009899 H ± 1.251640 - 0.668577 0.938088 H ± 1.282555 - 0.705381 - 0.888965
	Table 4.  Rotational Constants (MHz). B3LYP, ropt      Expt. [2] A    22 881 22 736.192 853(299) B    21 258 21 192.461 027(303) C    13 452 13 383.163 814(289)
	[1] M.K.Kemp and W.H.Flygare, J.Am.Chem.Soc. 90,6267(1968).
	[2] S.Thorwirth, R.Gendriesch, H.S.P.Müller, F.Lewen, and G.Winnewisser, J.Mol.Spectrosc. 201,323(2000).
	[3] S.Thorwirth, H.S.P.Müller, and G.Winnewisser, J.Mol.Spectrosc. 199,116(2000).
	CH2NH		(CH3)2NH		CF2NH
	trans-syn-Propenimine			trans-anti-Propenimine
	trans-Ethanimine			cis-Ethanimine
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	Molecules/Nitrogen
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						Last Modified 2 March 2005