4,4'-Oxybispyridine and 4,4'-Selenobispyridine

4,4'-Oxybispyridine, C₁₀H₈N₂O, and 4,4'-selenobispyridine, C₁₀H₈N₂Se) both adopt twist conformations with twist angles 69.2 (2) and 65.7 (2)°, respectively. The C-O bond lengths are 1.375 (4) and 1.373 (4) Å with the C-O-C angle 121.1 (2)°. The C-Se bond lengths are 1.913 (3) and 1.913 (4) Å with the angle at the Se atom 100.40 (14)°. The asymmetric coordination to the chalcogen atom, evidenced by the dissimilar exocyclic angles at the bridgehead C atoms, is no doubt a consequence of steric interaction between the proximal H atoms ortho to the latter.

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