biostudies-literatureUnknown17(5)Yan LDinuclear rhodium complexes represent a distinct class of transition-metal compounds, exhibiting unique reactivity enabled by close metal-metal proximity. However, despite extensive investigations, access to highly reduced Rh₂ complexes has remained a challenge due to their intrinsic instability. Herein, we report the synthesis and characterization of a series of dirhodium complexes in the formal oxidation states of Rh^II ₂, Rh^I ₂, and Rh⁰ ₂, supported by a flexible macrocyclic bis(pyridinediimine) (PDI₂) ligand. Single-crystal X-ray diffraction analysis revealed the crystal structure of the Rh₂ complexes. The PDI₂ ligand system flexibly adapts both structure and electronics across Chemical science2637-2645https://www.ebi.ac.uk/biostudies/studies/S-EPMC12687367biostudies-literatureLow-oxidation state dirhodium complex produced by four-electron reduction of dirhodium(ii) complex supported by a flexible macrocyclic ligand.PMC12687367Yan LMoriyama TMorimoto YMuratsugu STada MAkita YYamashita MfalseLow-oxidation state dirhodium complex produced by four-electron reduction of dirhodium(ii) complex supported by a flexible macrocyclic ligand.Dinuclear rhodium complexes represent a distinct class of transition-metal compounds, exhibiting unique reactivity enabled by close metal-metal proximity. However, despite extensive investigations, access to highly reduced Rh₂ complexes has remained a challenge due to their intrinsic instability. Herein, we report the synthesis and characterization of a series of dirhodium complexes in the formal oxidation states of Rh^II ₂, Rh^I ₂, and Rh⁰ ₂, supported by a flexible macrocyclic bis(pyridinediimine) (PDI₂) ligand. Single-crystal X-ray diffraction analysis revealed the crystal structure of the Rh₂ complexes. The PDI₂ ligand system flexibly adapts both structure and electronics across 2026-01-01T00:00:00Z2026 Feb2026-07-15T06:41:43.726Z2026-06-30T03:23:33.103ZS-EPMC126873674137814310.1039/d5sc07037f