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We report the high-capacity and selective uptake of Cr(VI) from water using the coordination polymer silver bipyridine acetate (SBA, [Ag(4,4'-bipy)][CH

Following the seminal theoretical work on the pleated β-sheet published by Pauling and Corey in 1951, the rippled β-sheet was hypothesized by the same authors in 1953. In the pleated β-sheet the interacting β-strands have the same chirality, whereas in the rippled β-sheet the interacting β-strands are mirror-images. Unlike with the pleated β-sheet that is now common textbook knowledge, the rippled β-sheet has been much slower to evolve. Much of the experimental work on rippled sheets came from groups that study aggregating racemic peptide systems over the course of the past decade. This includes MAX1/DMAX hydrogels (Schneider), L/D-KFE8 aggregating systems (Nilsson), and racemic Amyloid β mixtures (Raskatov). Whether a racemic peptide mixture is "ripple-genic" (

We report the crystal structures of four different neutral lanthanide (Ln = La, Nd, Eu and Gd) metal–organic frameworks based on the organic linker 2,6-naphthalenedicarboxylate (NDC). The materials are three-dimensional and crystallize in three distinct topologies, with distinct bonding modes of NDC and lanthanide coordination numbers ranging from seven to nine and varying geometry. We denote our materials SLUG-49 [La6(NDC)9(DMF)3·6 DMF], -50 [Nd2(NDC)3O(DMF)2], -51 [Eu2(NDC)3(DMF)2·DMF], and -52 [Gd4(NDC)6(DMF)4] (DMF = N,N-dimethylformamide). The structures exhibit similar thermal decomposition profiles and infrared spectra. The Eu(III)-based material exhibits a sharp red-orange luminescence at 613 nm with a quantum efficiency of 3.56%.

We report the first example of linker modification for an N-donor Ag-based cationic material while maintaining and in some cases increasing the anion exchange capacity. Cationic silver(I) pyrazine nitrate selectively traps harmful oxo-anions from water such as permanganate, perrhenate and a variety of α,ω-alkanedicarboxylates. We chose these anions as initial examples of exchange for potential water purification. The host-guest interaction between the cationic layers of π-stacked silver pyrazine polymers and the incoming/outgoing interlamellar anions allows for the exchange. The exchange capacity over 24 h reached 435 and 818 mg/g for permanganate and perrhenate, respectively, a record for a crystalline metal-organic material and over five times the exchange capacity compared to commercial resin. The material also undergoes organic exchange as an analog for pharmaceutical waste, some of which have a carboxylate functionality at the neutral pH range typical of natural water sources. Both the as-synthesized and exchanged materials are characterized by a variety of analytical techniques.