Tetradentate metalloenediynes with strong imine and weaker thioether coordination serve as a geometrically non-rigid switch to drive thermal Bergman cyclization.

A tetradentate tripodal ligand containing 2-amino-oxazoline moieties has been developed. This system tautomerizes upon chelation of a metal ion, forming a flexible cavity capable of accommodating ligands via an intramolecular hydrogen bonding network.

Tetradentate bis(pyridyltriazole) ligands containing aromatic spacers of different sizes react with Cu(2+) to produce metallo-supramolecular hosts that bind 1,4-diazabicyclo[2.2.2]octane molecules internally.

The coupling of tetrazotised 1,8-diaminonaphthalene with 1,3-dicarbonyl compounds [acetylacetone,methylacetoacetate and acetoacetanilide] yielded a new series of tetradentate ligand systems. Analytical, IR,1H NMR and mass spectral data indicate that the compounds exist in the intramolecularly hydrogen bondeddihydrazone form. Dibasic tetradentate N2O2 coordination of these compounds in their [ML...

Group 4 metal initiators with a tetradentate bis(phenolato) ligand polymerized meso-lactide efficiently under ring-opening to give syndiotactic polylactide. L-Lactide was converted faster than rac-lactide and meso-lactide.

A cobalt(ii) complex supported by the new tetradentate polypyridyl ligand PY4 is an electrocatalyst for the reduction of protons to hydrogen and can operate in 50% aqueous media.

One-pot reduction of HAuCl4 in a DMF solution containing a porphyrin-cored tetradentate passivant gives horizontal porphyrin monolayer-coated gold nanoparticles, whose particle size is significantly smaller than that made by using monodentate passivants under identical conditions.

A new triple-decker dinuclear sandwich-type dysprosium complex based on both the phthalocyanine ligand and the tetradentate Schiff base ligand was synthesized, which is of interest for synthetic chemistry and also shows single-molecule magnetic behaviour.

The 6-amino-6-methyl-1,4-diazepine framework is a readily available neutral 6-electron ligand moiety, suitable to support cationic group 3 metal alkyl catalysts; it also provides convenient access to tri- and tetradentate monoanionic ligand derivatives.