No abstract

No abstract

Biguanidine‐functionalized chitosan was synthesized and combined with palladium nanoparticles to yield a recyclable, environmentally benign, heterogeneous catalytic system for the Suzuki–Miyaura C–C coupling reaction. The catalyst was characterized using various techniques. The catalyst was used in Suzuki cross‐coupling reactions of various aryl halides, including less reactive chlorobenzenes, with phenylboronic acid to give biaryls without any additive or ligand. A reusability test demonstrated that the catalyst was highly efficient even after six runs. Solid‐phase poisoning and leaching tests indicated that the catalyst has a heterogeneous nature. Copyright © 2016 John Wiley & Sons, Ltd.

n or {(pipzH 2 )[Zn(py-2,3-dc) 2 ]Á-4H 2 O} n , where py-2,3-dcH 2 is pyridine-2,3-dicarboxylic acid and pipz is piperazine, was obtained by the reaction of zinc(II) nitrate tetrahydrate with (pipzH 2 )(py-2,3-dc) as a protontransfer compound in aqueous solution. Each Zn II (site symmetry 1) is coordinated in a distorted octahedral geometry by four O atoms and two N atoms from two bidentate (py-2,3dc) 2À ligands, which also act as bridging ligands between Zn II atoms. The four donor atoms of the two coplanar (py-2,3-dc) 2À anions form a square-planar arrangement around the Zn II centre. In the crystal structure, extensive O-HÁ Á ÁO, N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds, as well as ion pairing andstacking [with a distance of 3.8693 (8) Å between two aromatic rings] between different fragments, play an important role in the stabilization of the supramolecular structure.

A novel, green, and magnetically recoverable Fe3O4–adenine–Zn catalyst for the synthesis of 5-substituted tetrazoles and oxidation reactions.