Pb(II) metal-organic nanotubes based on cyclodextrins: biphasic synthesis, structures and properties

Two chiral lead metal-organic nanotubes (CD-MONT-2 and CD-MONT-3) based on beta-cyclodextrin (beta-CD) and gamma-cyclodextrin (gamma-CD) were synthesized through a biphasic solvothermal reaction. The lead ions were connected by two beta-CD or gamma-CD molecules through their glycosidic oxygen atoms to generate a discrete metal-organic nanotube containing a {Pb-14} or {Pb-16} metallamacrocycle, respectively. Guest solvents of cyclohexanol molecules were trapped in the cavity of the beta-CD-based nanotube, whereas there were no solvents in the cavity of the gamma-CD-based nanotube. These differences directly led to the formation of different 3D packing structures. Their properties including temperature-dependent photoluminescence, adsorption of I-2 molecules and thermal-decomposition behaviors were studied.