Pyridine
		Nitrogen and Deuterium
	Nuclear Quadrupole Coupling Constants
		in Pyridine  and  4-D-Pyridine
	Nitrogen and deuterium nqcc's in pyridine and 4-D-pyridine were measured by Heineking, Dreizler, and Schwarz [1].  Substitution structures were reported by Bak et al. [2] and Mata et al. [3].  A semi-experimental reSE structure was derived by Császár et al. [4].
	Nitrogen and deuterium nqcc's in pyridine and 4-D-pyridine were calculated on the substitution structures, the reSE, and on an ropt structure given by B3P86/6-31G(3d,3p) optimization.  These nqcc's are compared with the experimental values in Tables 1 - 4.  Structure parameters are compared in Table 5.  In Table 6, ropt atomic coordinates are given; in Table 7, ropt rotational constants.
	In Tables 1 - 4,  RMS is the root mean square difference between calculated and experimental nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation of the B3LYP/6-31G(df,3p) model for calculation of deuterium nqcc's, and the B3PW91/6-311+G(df,pd) model for nitrogen.
	Table 1. Nitrogen nqcc's in Pyridine (MHz).  Calculation was made on the rs structures of Bak et al. [2] and Mata et al. [3].     Calc /Bak Calc /Mata Expt. [1]     14N Xaa - 4.889 - 4.905 - 4.908(3) Xbb 1.451 1.450 1.434(3) Xcc 3.438 3.454 3.474(3)   RMS 0.026 (0.8 %) 0.015 (0.4 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)
	Table 2. Nitrogen nqcc's in Pyridine (MHz).  Calculation was made on the reSE [4] and ropt structures.     Calc /reSE Calc /ropt Expt. [1]     14N Xaa - 4.908 - 4.915 - 4.908(3) Xbb 1.437 1.436 1.434(3) Xcc 3.471 3.479 3.474(3)   RMS 0.002 (0.07 %) 0.005 (0.2 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)
	Table 3.  Deuterium and Nitrogen nqcc's in 4-D-Pyridine.  Calculation was made on the rs structures of Bak et al. [2] and Mata et al. [3].     Calc /Bak Calc /Mata Expt. [1]      2H /kHz Xaa 196.4 191.1 196(4) Xbb - 94.3 - 91.6 - 90(8) Xcc - 102.1 - 99.4 - 106(8)   RMS 3.4 (2.6 %) 4.8 (3.8 %) RSD 1.1 (0.9 %) 1.1 (0.9 %)   14N /MHz Xaa - 4.889 - 4.905 - 4.907(3) Xbb 1.451 1.450 1.442(5)   Xcc 3.438 3.454 3.465(5)   RMS 0.019 (0.6 %) 0.008 (0.2 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)
	Table 4.  Deuterium and Nitrogen nqcc's in 4-D-Pyridine.  Calculation was made on the reSE [4] and ropt structures.     Calc /reSE Calc /ropt Expt. [1]      2H /kHz Xaa 192.8 187.3 196(4) Xbb - 92.5 - 89.8 - 90(8) Xcc - 100.3 - 97.6 - 106(8)   RMS 4.0 (3.1 %) 7.0 (5.4 %) RSD 1.1 (0.9 %) 1.1 (0.9 %)   14N /MHz Xaa - 4.908 - 4.915 - 4.907(3) Xbb 1.437 1.436 1.442(5)   Xcc 3.471 3.479 3.465(5)   RMS 0.005 (0.1 %) 0.010 (0.3 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)
	Table 5. Molecular structure parameters (Å and degrees).    rs [2]  rs [3]  reSE [4]   ropt N(1)C(2) 1.3402 1.3376 1.3362(5) 1.3336 C(2)C(3) 1.3945 1.3938 1.3902(4) 1.3904 C(3)C(4) 1.3944 1.3916 1.3890(4) 1.3885 C(2)H(2) 1.0843 1.0865 1.0816(4) 1.0880 C(3)H(3) 1.0805 1.0826 1.0795(4) 1.0845 C(4)H(4) 1.0773 1.0818 1.0803(4) 1.0851 C(6)N(1)C(2) 116.83 116.94 116.90(4) 117.03 N(1)C(2)C(3) 123.88 123.80 123.80(4) 123.80 C(2)C(3)C(4) 118.53 118.53 118.54(4) 118.44 C(3)C(4)C(5) 118.33 118.40 118.42(4) 118.50 N(1)C(2)H(2) 115.88 116.01 115.90(5) 115.94 C(4)C(3)H(3) 121.30 121.36 121.34(5) 121.35
	Table 6. Atomic coordinates, ropt (More figures are shown than are significant.)      a (Å)    b (Å) N(1) 1.387656 0.0 C(2,6) 0.691147 ± 1.137206 C(3,5) - 0.698101 ± 1.193281 C(4) - 1.407970 0.0 H(2,6) 1.276872 ± 2.054047 H(3,5) - 1.205582 ± 2.151669 H(4) 2.493095 0.0
	Table 7.  Rotational Constants (MHz).  Normal species.   Calc. ropt   Expt. [3] A 6085.4 6039.2516(6) B 5849.7 5804.9116(6) C 2982.6 2959.2117(6)
	[1] N.Heineking, H.Dreizler, and R.Schwarz, Z.Naturforsch. 41a,1210(1986).
	[2] B.Bak, L.Hansen-Nygaard, and J.Rastrup-Andersen, J.Mol.Spectrosc. 2,361(1958).
	[3] F.Mata, M.J.Quintana, and G.O.Sørensen, J.Mol.Struct. 42,1(1977).
	[4] A.G.Császár, J.Demaison, and H.D.Rudolph, J.Phys.Chem. A, 119(9),1731(2015).
	W.C.Bailey, J.Mol.Struct. (Theochem) 541,195(2001).
	G.O.Sørensen, L.Mahler, and N.Rastrup-Andersen, J.Mol.Struct. 20,119(1974):  rs structure.
	Benzene-d1			Fluorobenzene-d1			Pyrazine
	Pyridine-N-O			2,6-Difluoropyridine			2,6-Lutidine
	Pyrimidine			2-Chloropyridine			1,2,4-Triazine
	2-Fluoropyridine			2-Bromopyridine			1,3,5-Triazine
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	Molecules/Deuterium
	Molecules/Nitrogen
	Pyridines
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						Last Modified 29 Oct 2014