Face-Capped M4L4 Tetrahedral Metal-Organic Cage: Iodine Capture and Release, Ion Exchange, and Electrical Conductivity.

An M⁴L₄ type metal-organic cage (MOC-19) has been synthesized from the one-pot reaction of tri(pyridinylmethylene)phenylbenzeneamine (TPBA) with hydrated Zn(ClO₄)₂ under mild conditions and characterized by single-crystal X-Ray diffraction. Iodine capture studies show that the porous crystals of MOC-19 exhibit a versatile behavior to accumulate iodine species not only in vapor (for I₂) but also in solution (for I₂ and I₃⁻), and anion-exchange experiments indicate the capacity to extract IO₃⁻ anions from aqueous solution. Enrichment of iodine species from KI/I₂ aqueous solution proceeds facilely, revealing a pseudo-second-order kinetics of I₃⁻ adsorption. Furthermore, the electrical conductivity of MOC-19 single crystals could be significantly altered by I₂ inclusion. [ABSTRACT FROM AUTHOR]