Palladium complexes containing imino phenoxide ligands: synthesis, luminescence, and their use as catalysts for the ring-opening polymerization of rac-lactide

Abstract

The preparation, structural characterization, luminescence, and catalytic activity of three palladium(II) complexes bearing imino phenoxide ligands are reported. The X-ray studies revealed that the complexes are mononuclear with palladium centres coordinated in a square-planar coordination environment. Two of the complexes are emissive in solution at room temperature. The catalytic activities towards the ring-opening polymerization of rac-lactide (rac-LA) were tested. Polymers with moderate molecular weights and relatively broad dispersity (Ð) were obtained. Kinetic studies revealed that the polymerization followed first-order kinetics.

Graphical abstract

Electronic supplementary material

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Luminescent closed shell nickel(ii) pyridyl-azo-oximates and the open shell anion radical congener: molecular and electronic structure, ligand redox behaviour and biological activity

Luminescent nickel(ii) complexes have been synthesized using redox-active azo-oximes. The superior π-acidity of the organic backbone is a key to the isolation of Ni(ii) anion radicals.

[2,6-Bis(5-ethoxy-1,3-oxazol-2-yl)-4-methoxyphenyl-κ3N,C1,N′]bromidopalladium(II)

In the title compound, [PdBr(C₁₇H₁₇N₂O₅)], the Pd^II atom is coordinated by an N,C¹,N′-tridentate pincer ligand and a Br atom in a distorted square-planar geometry. In the crystal, mol­ecules are connected by C—H⋯Br and C—H⋯O hydrogen bonds, and π–π inter­actions between the oxazole and benzene rings [centroid–centroid distance = 3.7344 (19) Å], resulting in a three-dimensional supra­molecular structure.