Trinuclear {Co²⁺–M³⁺–Co²⁺} complexes catalyze reduction of nitro compounds

Abstract

This work presents synthesis and characterization of trinuclear {Co(2+)-Co(3+)-Co(2+)} and {Co(2+)-Fe(3+)-Co(2+)} complexes with accessible peripheral Co(ii) ions. Both trinuclear complexes function as efficient reusable heterogeneous catalysts for the selective reduction of assorted nitro compounds to the corresponding amines. The mechanistic investigations suggest the involvement of a Co(ii)-Co(i) cycle in the catalysis.

Cobalt Complexes Catalyze Reduction of Nitro Compounds: Mechanistic Studies

“…Presence of redox tunable cobalt center in complexes 1–4 created an opportunity to explore their role in redox‐driven catalytic reactions . We selected nitro reduction reaction which is well‐known to proceed via the mediation of a redox‐sensitive metal ,,. We narrowed down to hydrazine hydrate as the reducing agent for its easy handling and benign by‐products .…”

“…Reduction of aliphatic nitro compounds remains a major challenge and restricts the wider applicability of any catalytic system ,,,. We selected nitrocyclopentane and tert ‐nitrobutane as the aliphatic nitro substrates for testing the present cobalt complexes (Entries 24 and 25).…”

Ethylene Polymerization Using Site‐Selective Pyridine‐Amide Based Iron Complexes

“…A variety of pyridine‐amide based transition metal complexes have been reported in the literature, such as cobalt(III), cobalt (II), iron(II),, iron(III),, manganese(II), nickel(II),, copper(II), rhodium(II), and ruthenium(III) ,. These studies indicated that designing of organic ligands and properly choosing metal ions are keys to create target transition metal‐based coordination complexes.…”

“…[11] Such coordination complexes resulted in precise control over the placement of molecular components resulting in interesting structural topologies [12][13][14][15][16][17][18][19][20] and tailor-made properties. [21][22][23][24] A variety of pyridine-amide based transition metal complexes have been reported in the literature, such as cobalt (III), [25][26][27][28][29][30][31][32] cobalt (II), [33] iron(II), [34,35] iron(III), [34,35] manganese(II), [36] nickel(II), [37,38] copper(II), [39] rhodium(II), [40][41][42] and ruthenium (III). [43,44] These studies indicated that designing of organic ligands and properly choosing metal ions are keys to create target transition metal-based coordination complexes.Coordination complexes with late transition metal ions have attracted current attention for ethylene oligomerization or polymerization because of their unique catalytic behavior.…”

Catalytic Application of Tactically Aligned Cd(II)‐Based Luminescent 3D‐Supramolecular Networks

“…The cogent design and synthesis of innovative CPs is an ongoing topic of research for exploration of the wide range of new complexes with predetermined physicochemical properties . The scope and diverseness of the self‐assembled structures which can be designed depends on various types of metal−ligand interactions, hydrogen bonding and other weak interactions . The structural attributes of these coordination polymers also influence by counter ion, metal‐to‐ligand ratios, and solvent.…”