Synthesis and structural analysis of 2,11-diaza[3.3](3,5)pyridinophane

Abstract

A possible bidentate receptor with two kinds of nitrogen atoms, 2,11-diaza[3.3](3,5)pyridinophane 1, was synthesized. A VT ¹H NMR study and ab initio MO calculations indicated that the two conformers of 1, boat–boat and chair–boat, have almost the same stabilities. The free energy barrier ΔG^‡ for the conformational change is estimated to be 10.4 kcal mol⁻¹ (T_c = −55 °C). An X-ray crystallographic study revealed that 1 forms a hydrogen-bonding network in the crystalline state.