From Metal-Organic Framework to Porous Carbon Polyhedron: Toward Highly Reversible Lithium Storage.

By application of a newly designed T-shaped ligand 5-(4-pyridin-4-yl-benzoylamino)isophthalic acid (HPBAI) to assemble with Zn(II) ions under solvothermal conditions, a novel porous polyhedral metal-organic framework (Zn-PBAI) with pcu topology has been obtained. When treated as a precursor by annealing of Zn-PBAI at various temperatures, porous carbon polyhedra (PCP) were prepared and tested as an anode material for lithium-ion batteries. The results show that PCP carbonized at 1000 °C (PCP-1000) manifest the highest reversible specific capacity of about 1125 mAh g at a current of 500 mA g after 200 cycles, which is supposed to benefit from the large accessible specific area and high electric conductivity.

Temperature-dependent guest-driven single-crystal-to-single-crystal ligand exchange in a two-fold interpenetrated Cd(II) grid network.

A doubly interpenetrated square-grid coordination polymer {[Cd(ImBNN)(2)(CF(3)SO(3))(2)])guest}(n) (1) (guest = C(7)H(8) and ImBNN = 2,5-bis[4'-(imidazol-1-yl)phenyl]-3,4-diaza-2,4-hexadiene) that contains cavities able to accommodate toluene guest molecules has been assembled by the reaction of the Schiff base ligand ImBNN and Cd(CF(3)SO(3))(2). The framework 1 shows dynamism in either temperature-dependent expansion and shrinkage or cooperatively temperature-dependent guest-driven ligand exchange at the metal center. Studies of guest removal/uptake by heating in a vacuum, cooling in air, and then heating in toluene at reflux have revealed a series of single-crystal-to-single-crystal structural transformations: complex 1 lost toluene guests and captured water molecules to give guest-free 1 b via a proposed metastable phase 1 a, and 1 b could readsorb toluene guests to give 1', which represents a restored 1.