Z. Dega‐Szafran, Z. Kosturkiewicz, E. Tykarska
Feb 17, 1997
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0
Influential Citations
12
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Pyridine N-oxides form two types of crystalline complexes with phentachlorophenol, with 1:1 and 1:2 base-to-acid ratios. The 1:2 complex of 2,6-dimethylpyridine N-oxide with pentachlorophenol crystallizes in space group P1 with a = 7.335(1) A , b = 11.324(2) A , c = 15.824(2) A , α = 100.38(1)°, β = 94.63(1)°, γ = 106.60(1)°, V = 1226.7(6) A 3 and Z = 2. The structure has been refined to R = 0.046 for 3408 observed Mo Kα reflections. The oxygen atom of the N-oxide group accepts hydrogen bonds from two molecules of pentachlorophenol, with Otctdot;O distances of 2.639(5) and 2.642(5) A and OHO angles of 141.2° and 157.6°, respectively. Both NOtctdot;HO bridges are formed in, or near, the directions of the electron lone-pairs of the N-oxygen atom. The two pentachlorophenol rings (A and B) are nearly parallel to each other and they are almost perpendicular to the pyridine ring. FTIR spectra of eleven 1:2 complexes in the solid state are similar and independent of the proton acceptor properties of the N-oxides. Five lines in the 35 Cl NQR spectra of the 1:2 complexes provide evidence that both molecules of pentachlorophenol are equivalent. In CHCl 3 solution, all the 1:2 complexes exist as a mixture of the 1:1 complex and pentachlorophenol.