Guest-induced Assembly of Bis(thiosemicarbazonato) Zinc(II) Coordination Nanotubes

A Zn^II complex of the dianionic tetradentate ligand formed by deprotonation of glyoxal-bis(4-phenyl-3-thiosemicarbazone) (H₂gtsp) is a [3+3] trinuclear triangular prism. Recrystallization of this complex in the presence of either CO₂, CS₂, or CH₃CN leads to the formation of [4+4] open-ended charge-neutral tetranuclear coordination nanotubes, approximately 2 nm in length and with internal dimensions large enough to accommodate linear guest molecules, which serve to template their formation. Upon removal of the templating molecules the nanotubes demonstrated reversible sorption of CO₂ with an isosteric enthalpy of sorption of 28 kJ mol⁻¹ at low loading.