Pyridinophane Bridging Group Chemistry: Synthesis and Reactions of 1,2,9,10-Tetra-chloro[ 2,2](2,6)pyridinophane-1,9-diene

Abstract

Oxidation and polychlorination of 2,11-dithia[3,3](2,6)pyridinophane (II) gives high yields of the corresponding octachloro bissulfone (14) which, on vacuum pyrolysis, readily loses SO₂ and Cl₂ sequentially, giving eventually a good yield of orange 1,2,9,10-tetrachloro[2,2](2,6)pyridinophane-1,9-diene (4). Nucleophilic addition and substitution reactions of the dichloroethene bridges of (4) are described. None of the [2,2]metacyclophane diene systems undergoes spontaneous or photoinduced valence tautomerism to a 10b,10c-diazapyrene (2).