SEARCH Articles Figures Tables 2-2 -Bipyridyl crown ether ligand Bipyridyl Bipyridyl ligands Bipyridyl transition metal recognition Crown ether ligands, containing bipyridyl transition metal recognition Ethers metalation Ethers metals Ligand containing Ligand recognition Ligand sites Ligands, metal-containing Metal etherates Metal sites Site transition Transition ligand Transition metals ligands