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].
 
Nitrogen and deuterium nqcc's in pyridine and 4-D-pyridine were calculated on the substitution structures, and on the B3P86/6-31G(3d,3p) optimized structure [4].  These nqcc's are compared with the experimental values in Tables 1-6.  Structure parameters are compared in Table 7.  In Table 8, ropt atomic coordinates are given; in Table 9, rotational constants.
 
In Tables 1-6,  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.  Deuterium and Nitrogen nqcc's in 4-D-Pyridine.  Calculation was made on the rs structure of Bak et al. [2].
   










Calc.
Expt. [1]
   






 2H /kHz Xaa 196.4 196(4)
Xbb - 94.3 - 90(8)
Xcc - 102.1 - 106(8)
 
RMS 3.4 (2.6 %)
RSD 1.1 (0.9 %)
 
14N /MHz Xaa - 4.889 - 4.907(3)
Xbb 1.451 1.442(5)
  Xcc 3.438 3.465(5)
 
RMS 0.019 (0.6 %)
RSD 0.030 (1.3 %)
 


 







   







Table 2. Nitrogen nqcc's in Pyridine (MHz).  Calculation was made on the rs structure of Bak et al. [2].
   










Calc.
Expt. [1]
   






14N Xaa - 4.889 - 4.908(3)
Xbb 1.451 1.434(3)
Xcc 3.438 3.474(3)
 
RMS 0.026 (0.8 %)
RSD 0.030 (1.3 %)
 
 
 
   







Table 3.  Deuterium and Nitrogen nqcc's in 4-D-Pyridine.  Calculation was made on the rs structure of Mata et al. [3].
   










Calc.
Expt. [1]
   






 2H /kHz Xaa 191.1 196(4)
Xbb - 91.6 - 90(8)
Xcc - 99.4 - 106(8)
 
RMS 4.8 (3.8 %)
RSD 1.1 (0.9 %)
 
14N /MHz Xaa - 4.905 - 4.907(3)
Xbb 1.450 1.442(5)
  Xcc 3.454 3.465(5)
 
RMS 0.008 (0.2 %)
RSD 0.030 (1.3 %)
 
 
   







Table 4. Nitrogen nqcc's in Pyridine (MHz).  Calculation was made on the rs structure of Mata et al. [3].
   










Calc.
Expt. [1]
   






14N Xaa - 4.905 - 4.908(3)
Xbb 1.450 1.434(3)
Xcc 3.454 3.474(3)
 
RMS 0.015 (0.4 %)
RSD 0.030 (1.3 %)
 
 
 
   







Table 5.  Deuterium and Nitrogen nqcc's in 4-D-Pyridine.  Calculation was made on the ropt structure.
   










Calc.
Expt. [1]
   






 2H /kHz Xaa 187.3 196(4)
Xbb - 89.8 - 90(8)
Xcc - 97.6 - 106(8)
 
RMS 7.0 (5.4 %)
RSD 1.1 (0.9 %)
 
14N /MHz Xaa - 4.915 - 4.907(3)
Xbb 1.436 1.442(5)
  Xcc 3.479 3.465(5)
 
RMS 0.010 (0.3 %)
RSD 0.030 (1.3 %)
 
 
   







Table 6. Nitrogen nqcc's in Pyridine (MHz).  Calculation was made on the ropt structure.
   










Calc.
Expt. [1]
   






14N Xaa - 4.915 - 4.908(3)
Xbb 1.436 1.434(3)
Xcc 3.479 3.474(3)
 
RMS 0.005 (0.2 %)
RSD 0.030 (1.3 %)
 
 
 
 
Table 7. Molecular structure parameters (Å and degrees).
 
 rs [2]  rs [3]   ropt
N(1)C(2) 1.3402 1.3376 1.3336
C(2)C(3) 1.3945 1.3938 1.3904
C(3)C(4) 1.3944 1.3916 1.3885
C(2)H(2) 1.0843 1.0865 1.0880
C(3)H(3) 1.0805 1.0826 1.0845
C(4)H(4) 1.0773 1.0818 1.0851
C(6)N(1)C(2) 116.83 116.94 117.03
N(1)C(2)C(3) 123.88 123.80 123.80
C(2)C(3)C(4) 118.53 118.53 118.44
C(3)C(4)C(5) 118.33 118.40 118.50
N(1)C(2)H(2) 115.88 116.01 115.94
C(4)C(3)H(3) 121.30 121.36 121.35


 
 
Table 8. 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 9.  Rotational Constants (MHz).  Normal species.
 
Calc. ropt Calc. rs [3]   Expt. [3]
A 6085.4 6063.1 6039.2516(6)
B 5849.7 5819.6 5804.9116(6)
C 2982.6 2969.4 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] W.C.Bailey, J.Mol.Struct. (Theochem) 541,195(2001).

 








 








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/Nitrogen



Pyridines
 

 













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Last Modified 15 Nov 2003