Versatile Syntheses of Hemi-Cryptophanes and a Metallo-Cryptophane from a Hexa-Functionalized C-3v-Symmetrical Tribenzotriquinacene (TBTQ) Derivative

Wei J, Li Z-M, Jin X-J, et al. Versatile Syntheses of Hemi-Cryptophanes and a Metallo-Cryptophane from a Hexa-Functionalized C-3v-Symmetrical Tribenzotriquinacene (TBTQ) Derivative. Chemistry - An Asian Journal. 2015;10(5):1150-1158.A number of three-fold C-3v-symmetrical tribenzotriquinacene (TBTQ) cavitands were synthesized by a metamorphosis-to-half strategy, employing six-fold etherification reactions between the hexakis(chloromethyl)-TBTQ intermediate 2a and various 5-functionalized resorcinols. X-ray structure analyses of single crystals of the cavitands revealed limited rotational flexibility of the resorcinol bridging units, which enables an apical, nearly co-axial orientation of the three functional groups and, as a consequence, the construction of nanoscale cage-like molecules via covalent or coordination bonding. On this basis, two TBTQ-based hemicryptophanes were prepared from the TBTQ cavitands via covalent bond formation in good yields. A dumbbell-shaped TBTQ-based metallo-cryptophane was also synthesized in 34% yield by a solvothermal reaction between cadmium nitrate and two equivalents of the TBTQ-cavitand triacid, as confirmed by single-crystal X-ray diffraction and MALDI-ToF mass spectrometry