Coordination chemistry of Robson-type polyamine-dithiophenolate macrocycles: Syntheses, structures and magnetic properties of dinuclear complexes of first-row transition metals

The coordination chemistry of N-functionalized derivatives of Robson-type macrocyclic hexamine-dithiophenolate ligands (LR)2− is presented in this review. The ligands form mononuclear as well as dinuclear transition metal complexes of first row-transition metal ions. The bioctahedral transition metal complexes of the type [M2(LR)(μ-L′)]+ exhibit a rich coordination chemistry since the active coordination site L′ is accessible for a wide range of exogenous coligands. It is demonstrated that N-functionalization of the secondary NH groups influences many properties of the binuclear [MII2(LR)(μ-L′)]+ complexes, including color, molecular and electronic structure, hydrogen bonding interactions, redox potential, complex stability, and reactivity. The magnetic exchange interactions in these complexes both from an experimental as well as a theoretical point of view are also a subject of this article.