Molecular surface modification of silver chalcogenolate clusters.

This study presents a molecular surface modification approach to synthesizing a family of silver chalcogenolate clusters (SCCs) containing the same [Ag12S6] core and different surface-bonded organic ligands (DMAc or pyridines; DMAc = dimethylacetamide), with the aim of tuning the luminescence properties and increasing the structural stability of the SCCs. The SCCs displayed strong and tuneable luminescence emissions at 77 K (from green to orange to red) as influenced by the peripheral pyridine ligands. In addition, SCC 5 protected by pyridine molecules was stable in ambient air, humid air and even liquid water for a long time (up to 1 week), and it was more structurally stable than SCC 1 bonded with DMAc molecules under the same conditions. The high structural stability of SCC 5 can be explained by the ability of pyridine molecules to form strong coordination bonds with silver atoms. This study offers a new way of designing structurally stable metal nanoclusters with tuneable physicochemical properties.

Dual-functional ionic porous organic framework for palladium scavenging and heterogeneous catalysis.

Porous organic frameworks (POFs) with predesigned structures and tunable porosities have been widely studied in adsorption and heterogeneous catalysis. Introducing ionic structure into the framework endows POFs with new functionalities that may extend their applications. Here, we report new applications for a guanidinium-based ionic POF (IPOF-Cl) in palladium scavenging and heterogeneous catalysis. Due to the ionic framework and the porous structure, the IPOF-Cl displays fast adsorption kinetics and high adsorption capacities (up to 754 mg g-1) of Na2PdCl4 in aqueous solutions via a chemisorption (ion exchange) process. Significantly, it shows excellent scavenging activity towards trace amount of [PdCl4]2- in aqueous solution. More importantly, the loaded [PdCl4]2- species on the IPOF substrate are further reduced into ultrafine Pd nanoparticles with size of ∼2-5 nm. The obtained IPOF-Pd(0) nanocomposite containing uniformly distributed Pd nanoparticles and hierarchical porous structure demonstrates high activity in catalyzing a range of Suzuki coupling reactions. This study provides new routes for the development of ionic porous organic materials for applications in metal scavenging and catalysis.

Assembly of Discrete Chalcogenolate Clusters into a One-Dimensional Coordination Polymer with Enhanced Photocatalytic Activity and Stability.

Interlinking discrete supertetrahedral chalcogenolate clusters with conjugated bipyridine linkers form a one-dimensional coordination polymer, [Cd6Ag4(SPh)16(DMF)(H2O)(bpe)]n (1a), displaying a broader visible-light absorption and a narrower band gap than those of the discrete cluster. More importantly, the coordination polymer demonstrates enhanced activity and stability for the photocatalytic degradation of organic dye in water.