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Abstract Literature reports have demonstrated that Schiff-base-type ligands can serve as robust platforms for the synthesis of heterobimetallic complexes containing transition metals and the uranyl dication (UO22+). However, efforts have not advanced to include either synthesis of complexes containing second- or third-row transition metals or measurement of the redox properties of the corresponding heterobimetallic complexes, despite the significance of actinide redox in studies of nuclear fuel reprocessing and separations. Here, metalloligands denoted [Ni], [Pd], and [Pt] that contain the corresponding Group 10 metals have been prepared and a synthetic strategy to access species incorporating the uranyl ion (UO22+) has been explored, toward the goal of understanding how the secondary metals could tune uranium-centered redox chemistry. The synthesis and redox characterization of the bimetallic complex [Ni,UO2] was achieved, and factors that appear to govern extension of the chosen synthetic strategy to complexes with Pd and Pt are reported here. Infrared and solid-state structural data from X-ray diffraction analysis of the metalloligands [Pd] and [Pt] show that the metal centers in these complexes adopt the expected square planar geometries, while the structure of the bimetallic [Ni,UO2] reveals that the uranyl moiety influences the coordination environment of Ni(II), including inducement of a puckering of the ligand backbone of the complex in which the phenyl rings fold around the nickel-containing core in an umbrella-shaped fashion. Cyclic voltammetric data collected on the heterobimetallic complexes of both Ni(II) and Pd(II) provide evidence for uranium-centered redox cycling, as well as for the accessibility of other reductions that could be associated with Ni(II) or the organic ligand backbone. Taken together, these results highlight the unique redox behaviors that can be observed in multimetallic systems and design concepts that could be useful for accessing tunable multimetallic complexes containing the uranyl dication.
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Structural and Redox Interconversions of Sulfur Ligands of Transition Metal Complexes
The interactions between transition metals and sulfur have long been studied for potential applications in catalysis and energy storage and due to the relevance of these motifs in biological and geological systems. Complexes with sulfur-containing ligands can undergo redox transformations centered on sulfur as well as at the metal. Sulfur also readily catenates with other sulfur centers to form polysulfur motifs. Here, the synthesis and structures of notable examples of metal complexes with sulfur-containing ligands (sulfido, polysulfido, and polysulfanido) are described. Aspects of sulfur-centered redox, including spectroscopic and structural considerations, and future research opportunities are highlighted.
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- Award ID(s):
- 2047045
- PAR ID:
- 10410281
- Date Published:
- Journal Name:
- Comments on Inorganic Chemistry
- ISSN:
- 0260-3594
- Page Range / eLocation ID:
- 1 to 43
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1080/02603594.2023.2200174
