Donor‐Acceptor Tribenzotriquinacene‐Based Molecular Wizard Hats Bearing Three ortho‐Benzoquinone Units

Abstract

Two π-extended bay-bridged tribenzotriquinacenes ("TBTQ wizard hats") 12 and 16 bearing three mutually conjugated, alternating veratrole-type and ortho-benzoquinone units were synthesized. The electronic properties of these complementarily arranged, nonplanar push-pull systems are affected by the fusion with the rigid, C 3 -symmetric TBTQ core to a different extent, as revealed by X-ray structural analysis, UV-vis spectroscopy and cyclovoltammetry. The combination of three quinone units within the original TBTQ core and three veratrole-type bay bridging units in 12 gives rise to a more efficiently π-conjugated chromophore, as reflected by the shallower shape of wizard hat and its absorption in the visible up to 750 nm in comparison to 16. Congener 12 contains an aromatic 18-π electron system in contrast to the cross-conjugated analog 16. X-ray structure analysis of the precursor dodecaether 15 revealed the formation of a cage-like supramolecular dimer, in which the peripheral dioxane-type ether groups interlace by twelve noncovalent CÀ H•••••O bonds.

Molecular bowls for inclusion complexation of toxic anticancer drug methotrexate

“…1B and C ), with circa 90° angle between its fused indanes, 16 host MTX with the aromatics folded at ∼90° in aqueous media? First, the electron-rich surface 17 of the TBTQ moiety of 1 6+ ( Fig. 1C ) is expected to complement the electron-deficient pteridine from MTX.…”