Quinazoline
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Quinazoline
	Nitrogen nqcc tensors in quinazoline were calculated on a molecular structure optimized at the B3P86/6-31G(3d,3p) level of theory (ropt).  These calculated nqcc's are compared with the experimental values of McNaughton et al. [1] in Tables 1 and 2.  Structure parameters are given in Table 3, rotational constants and electric dipole moments in Table 4.
	In Tables 1 and 2, subscripts a,b,c refer to principal axes of the inertia tensor, subscripts x,y,z to principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the plane of the molecule.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	RMS is the root mean square difference between calculated and experimental nqcc's (percentage of average experimental nqcc).  RSD is the residual stand deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's (which may be taken as the uncertainty in calculated nqcc's, notwithstanding uncertainties in the calculated molecular structure).
	Table 1. 14N(15) nqcc's in Quinazoline (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.  This is N(1) in Ref. [1].     Calc. Expt. [1]     14N(15) Xaa 1.462 1.4547(35) Xbb - 4.533 - 4.5186 * Xcc 3.071 3.0639 * Xab - 0.219   RMS 0.010 (0.34 %) RSD 0.030 (1.3 %)   Xxx 1.470 Xyy 3.071 Xzz - 4.541 ETA 0.353 Øz,b 2.09 Øb,bi 1.39 Øz,bi** 3.48
	* Calculated here from experimental Xaa and Xbb - Xcc = -7.5826(75) MHz.
	** The z-axis makes an angle of 3.48o with the external bisector ('bi') of the CNC angle and tilts toward C(4).  See Table 3 for atomic numbering.
	Table 2. 14N(16) nqcc's in Quinazoline (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.  This is N(2) in Ref. [1].     Calc. Expt. [1]     14N(16) Xaa - 3.561 - 3.59205(179) Xbb - 0.321 - 0.3503 * Xcc 3.241 3.2417 * Xab - 2.368   RMS 0.025 (1.0 %) RSD 0.030 (1.3 %)   Xxx 1.442 Xyy 3.241 Xzz - 4.682 ETA 0.384 Øz,a 25.33 Øa,bi 27.41 Øz,bi**   2.08
	* Calculated here from experimental Xaa and Xbb - Xcc = -2.8914(62) MHz.
	** The z-axis makes an angle of 2.08o with the external bisector ('bi') of the CNC angle and tilts toward C(13).  See Table 3 for atomic numbering.
	Table 3. Quinazoline and Pyrimidine.  Selected molecular structure parameters, B3P86/6-31G(3d,3p) ropt (Å and degrees).  The complete structure of quinazoline is given here in Z-matrix format.   Quinazoline Pyrimidine   C(4)N(15) 1.3599 1.3328 N(15)C(13) 1.3093 1.3320 C(13)N(16) 1.3580 1.3320 N(16)C(10) 1.3116 1.3328 C(4)N(15)C(13) 116.38 115.70 N(15)C(13)N(16) 127.89 127.38 C(13)N(16)C(10) 115.81 115.70
	Table 4.  Quinazoline, ropt.  Rotational constants (MHz) and B3PW91/6-311+G(df,pd) calculated dipole moments (D).    Calc.     Expt. [1] A 3253.20 3229.85422(55) B 1283.94 1276.2106327(191) C   920.60   914.9869715(217) |µa|   2.85 |µb|   1.24
	[1] D.McNaughton, P.D.Godfrey, M.K.Jahn, D.A.Dewald, and J.-U.Grabow, J.Chem.Phys. 134,154305(2011).
	Pyrimidine		Phthalazine		Quinoxaline		1,10-Phenanthroline
	Acridine		Quinoline		Isoquinoline		Phenanthridine
	Table of Contents
	Molecules/Nitrogen
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						Last Modified 20 April 2011