A PCP Pincer Ligand for Coordination Polymers with Versatile Chemical Reactivity: Selective Activation of CO2 Gas over CO Gas in the Solid State.

A tetra(carboxylated) PCP pincer ligand has been synthesized as a building block for porous coordination polymers (PCPs). The air- and moisture-stable PCP metalloligands are rigid tetratopic linkers that are geometrically akin to ligands used in the synthesis of robust metal-organic frameworks (MOFs). Here, the design principle is demonstrated by cyclometalation with Pd(II) Cl and subsequent use of the metalloligand to prepare a crystalline 3D MOF by direct reaction with Co(II) ions and structural resolution by single crystal X-ray diffraction. The Pd-Cl groups inside the pores are accessible to post-synthetic modifications that facilitate chemical reactions previously unobserved in MOFs: a Pd-CH3 activated material undergoes rapid insertion of CO2 gas to give Pd-OC(O)CH3 at 1 atm and 298 K. However, since the material is highly selective for the adsorption of CO2 over CO, a Pd-N3 modified version resists CO insertion under the same conditions.

Separation of p-divinylbenzene by selective room-temperature adsorption inside Mg-CUK-1 prepared by aqueous microwave synthesis.

A new Mg(II) -based version of the porous coordination polymer CUK-1 with one-dimensional pore structure was prepared by microwave synthesis in water. Mg-CUK-1 is moisture-stable, thermally stable up to 500 °C, and shows unusual reversible soft-crystal behavior: dehydrated single crystals of the material selectively adsorb a range of organic molecules at ambient temperature and pressure. Both polar and apolar aromatic compounds, including pyridine, benzene, p-xylene, and p-divinylbenzene (p-DVB), are all readily adsorbed, while other isomers from complex mixtures of xylenes or DVBs are selectively excluded. The solvent-loaded structures have been studied by single-crystal X-ray diffraction. Time-dependent liquid sorption experiments using commercially available DVB demonstrate a high and rapid selective adsorption of p-DVB and exclusion of m-DVB and ethylvinylbenzene isomers.

Magnetism of linear [Ln3](9+) oxo-bridged clusters (Ln = Pr, Nd) supported inside a [R3PR'](+) phosphonium coordination material.

Two new isostructural phosphine coordination materials, Ln-PCM-21 (Ln = Pr, Nd), have been obtained using a tris(p-carboxylated) methyltriphenylphosphonium ligand that is formally dianionic when triply deprotonated, allowing access to materials based on uncommon metal-to-ligand ratios. The polymers of the formula [Ln3(mptbc)4]X·solv (X = Cl(-), NO3(-)) are cationic and contain unusual, linear oxo-bridged [Ln3](9+) clusters. Magnetic susceptibility data for both the Pr and Nd analogues has been compared to models based on three contrasting approaches.

Ship in a breakable bottle: fluoride-induced release of an organic molecule from a Pr(iii)-linked molecular cage.

A 3-dimensional networked molecular cage, , has been synthesized. This macrocycle-based framework was prepared from a solvothermal reaction involving a flexible organic building block, calix[4]pyrrole dibenzoic acid (H2), and Pr(NO3)3·6H2O. A unique feature of is that it retains free calix[4]pyrrole molecules in the framework pores. Treatment with a fluoride anion source serves to destroy the network and allows release of the organic guest. The net result is a 'molecular ship' in a 'breakable bottle'.