Tuning metal-metal interactions for cooperative small molecule activation

Chem Commun (Camb). 2021 Mar 21;57(23):2839-2853. doi: 10.1039/d0cc07721f. Epub 2021 Feb 24.

Abstract

Cluster complexes have attracted interest for decades due to their promise of drawing analogies to metallic surfaces and metalloenzyme active sites, but only recently have chemists started to develop ligand scaffolds that are specifically designed to support multinuclear transition metal cores. Such ligands not only hold multiple metal centers in close proximity but also allow for fine-tuning of their electronic structures and surrounding steric environments. This Feature Article highlights ligand designs that allow for cooperative small molecule activation at cluster complexes, with a particular focus on complexes that contain metal-metal bonds. Two useful ligand-design elements have emerged from this work: a degree of geometric flexibility, which allows for novel small molecule activation modes, and the use of redox-active ligands to provide electronic flexibility to the cluster core. The authors have incorporated these factors into a unique class of dinucleating macrocycles (nPDI2). Redox-active fragments in nPDI2 mimic the weak-overlap covalent bonding that is characteristic of M-M interactions, and aliphatic linkers in the ligand backbone provide geometric flexibility, allowing for interconversion between a range of geometries as the dinuclear core responds to the requirements of various small molecule substrates. The union of these design elements appears to be a powerful combination for analogizing critical aspects of heterogeneous and metalloenzyme catalysts.

Publication types

  • Review

MeSH terms

  • Biomimetic Materials / chemistry*
  • Catalysis
  • Catalytic Domain
  • Coordination Complexes / chemistry*
  • Ligands
  • Macrocyclic Compounds / chemistry
  • Metalloproteins / chemistry*
  • Metals / chemistry*
  • Molecular Structure
  • Oxidation-Reduction
  • Structure-Activity Relationship
  • Transition Elements / chemistry*

Substances

  • Coordination Complexes
  • Ligands
  • Macrocyclic Compounds
  • Metalloproteins
  • Metals
  • Transition Elements