Dinuclear cobalt(II) complexes with double phosphate ester bridges and tetradentate ligands having anisole or quinoline appendages

Phosphate esters provide a rigid and stable polymeric backbone in nucleic acids. Metal complexes with phosphate ester groups have been synthesized as structural and spectroscopic models of phosphate-containing enzymes. Dinucleating ligands are used extensively to synthesize model complexes since they provide the support required to stabilize such complexes. The crystal structures of two dinuclear CoII complexes, namely bis(μ-diphenyl phosphato-κ2 O:O′)bis({2-methoxy-N,N-bis[(pyridin-2-yl)methyl]aniline-κ4 N,N′,N′′,O}cobalt(II)) bis(perchlorate), [Co(C12H10O4P)2(C19H19N3O)2](ClO4)2, and bis(μ-diphenyl phosphato-κ2 O:O′)bis({N,N-bis[(pyridin-2-yl)methyl]quinolin-8-amine-κ4 N,N′,N′′,O}cobalt(II)) bis(perchlorate), [Co(C12H10O4P)2(C21H18N4)2](ClO4)2, with tetradentate 2-methoxy-N,N-bis[(pyridin-2-yl)methyl]aniline (L 1) and N,N-bis[(pyridin-2-yl)methyl]quinolin-8-amine (L 2) ligands are reported. The complexes have similar structures, with distorted octahedral geometries around the metal centres. Both are centrosymmetric (Z′ = 0.5), with the CoII centres doubly bridged by diphenyl phosphate ester groups. A number of aromatic–aromatic interactions are present and differ between the two complexes as the anisole group in L 1 is replaced by a quinoline group in L 2. A detailed study of these interactions is presented.

Design and synthesis of a dinucleating ligand system with varying terminal donor functions that provides no bridging donor and its application to the synthesis of a series of FeIII–μ-O–FeIII complexes

We have developed the dinucleating ligands H4julia, susan, and H4hildeMe2 and present their μ-oxo diferric complexes.

New mechanistic insight into intramolecular arene hydroxylation initiated by (μ-1,2-peroxo)diiron(iii) complexes with dinucleating ligands

Intramolecular arene hydroxylation initiated by (μ-1,2-peroxo)diiron(iii) complexes (2-R) with dinucleating ligands (R-L) involves a diiron(iv)-oxo species.