N3C3H3
		Nitrogen
	Nuclear Quadrupole Coupling Constants
		in 1,2,4-Triazine
	Nitrogen nqcc's in 1,2,4-triazine were calculated on a structure given by B3P86/6-31G(3d,3p) optimization.  These are compared with the experimental nqcc's of Palmer and Christen [1] in Tables 1 - 3.  Structure parameters are given in Table 4, atomic coordinates in Table 5.
	In Tables 1 - 3, 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 plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	RMS is the root mean square difference between calculated andexperimental nqcc's (percent of the average magnitude 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 nqcc's.
	Table 1.  N(1) nqcc's in 1,2,4-Triazine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.   Calc. Expt. [1]   14N(1) Xaa - 5.894 - 5.39(23) Xbb 1.963 1.96(33) Xcc 3.931 3.43(33) |Xab| 0.715   RMS 0.41 (11.4 %) RSD 0.030 (1.3 %)   Xxx 2.027 Xyy 3.931 Xzz - 5.958 ETA 0.320 Øz,a   5.16 Øa,bi 14.60 Øz,bi*   9.44
	* The z-axis makes an angle of 9.44o with the external bisector ( 'bi' ) of the C(6)N(1)N(2) angle, and tilts toward the adjacent nitrogen, N(2).
	Table 2.  N(2) nqcc's in 1,2,4-Triazine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.   Calc. Expt. [1]   14N(2) Xaa - 2.627 - 2.28(15) Xbb - 0.595 - 0.66(24) Xcc 3.222 2.93(24) |Xab| 3.782   RMS 0.26 (13.5 %) RSD 0.030 (1.3 %)   Xxx 2.305 Xyy 3.222 Xzz - 5.527 ETA 0.166 Øz,a 37.48 Øa,bi 47.22 Øz,bi*   9.74
	* The z-axis makes an angle of 9.74o with the external bisector ( 'bi' ) of the N(1)N(2)C(3) angle, and tilts toward the adjacent nitrogen, N(1).
	Table 3.  N(4) nqcc's in 1,2,4-Triazine (MHz).  Calculation was made on the B3P86/6-31G(3d,3p) ropt structure.   Calc. Expt. [1]   14N(4) Xaa - 4.466 - 5.02(17) Xbb 0.596 0.80(25) Xcc 3.870 4.21(25) |Xab| 1.663   RMS 0.39 (11.8 %) RSD 0.030 (1.3 %)   Xxx 1.094 Xyy 3.870 Xzz - 4.964 ETA 0.559 Øz,a 16.65 Øa,bi 16.11 Øz,bi*   0.54
	* The z-axis makes an angle of 0.54o with the external bisector ( 'bi' ) of the C(3)N(4)C(5) angle, and tilts toward C(3).
	Table 4.  1,2,4-Triazine.  Structure parameters ropt (Å and degrees).   N(1)N(2) 1.3250 N(2)C(3) 1.3317 C(3)N(4) 1.3348 N(4)C(5) 1.3241 C(5)C(6) 1.3928 C(6)N(1) 1.3291 C(3)H(3) 1.0864 C(5)H(5) 1.0878 C(6)H(6) 1.0854 N(1)N(2)C(3) 118.07 N(2)C(3)N(4) 127.19 C(3)N(4)C(5) 114.22 N(4)C(5)C(6) 120.63 C(5)C(6)N(1) 121.60 C(6)N(1)N(2) 118.28 N(2)C(3)H(3) 115.43 C(4)C(5)H(5) 117.64 C(5)C(6)H(6) 122.32
	Table 5.  1,2,4-Triazine.  Atomic coordinates, ropt.    a (Å)  b (Å) N(1) - 1.2361 - 0.3284 N(2) - 0.9551 0.9435 C(3) - 0.3788 - 1.2607 N(4) 0.3483 1.2162 C(5) 0.9735 - 0.9272 C(6) 1.3557 0.3405 H(3) - 0.7227 - 2.2902 H(5) 0.6041 2.2720 H(6) 1.7503 - 1.6886
	[1] M.H.Palmer and D.Christen, J.Mol.Struct. 612,401(2002).
	1,2,3-Triazine			1,3,5-Triazine			Pyridazine
	Table of Contents
	Molecules/Nitrogen
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						Last Modified 8 Jan 2004