In polynuclear biological active sites, multiple electrons are needed for turnover, and the distribution of these electrons among the metal sites is affected by the structure of the active site. However, the study of the interplay between structure and redox distribution is difficult not only in biological systems but also in synthetic polynuclear clusters since most redox changes produce only one thermodynamically stable product. Here, the unusual chemistry of a sterically hindered trichromium complex allowed us to probe the relationship between structural and redox isomerism. Two structurally isomeric trichromium imides were isolated: asymmetric terminal imide ( tbs L)Cr 3 (NDipp) and symmetric, μ 3 -bridging imide ( tbs L)Cr 3 (μ 3 –NBn) (( tbs L) 6− = (1,3,5-C 6 H 9 (NC 6 H 4 - o -NSi t BuMe 2 ) 3 ) 6− ). Along with the homovalent isocyanide adduct ( tbs L)Cr 3 (CNBn) and the bisimide ( tbs L)Cr 3 (μ 3 –NPh)(NPh), both imide isomers were examined by multiple-wavelength anomalous diffraction (MAD) to determine the redox load distribution by the free refinement of atomic scattering factors. Despite their compositional similarities, the bridging imide shows uniform oxidation of all three Cr sites while the terminal imide shows oxidation at only two Cr sites. Further oxidation from the bridging imide to the bisimide is only borne at the Cr site bound to the second, terminal imido fragment. Thus, depending on the structural motifs present in each [Cr 3 ] complex, MAD revealed complete localization of oxidation, partial localization, and complete delocalization, all supported by the same hexadentate ligand scaffold.
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A DFT Survey of the Effects of d‐Electron Count and Metal Identity on the Activation and Functionalization of C−H Bonds for Mid to Late Transition Metals
The contribution of metal identity to the activation and functionalization of methane by a series of three‐coordinate imide complexes is evaluated
- PAR ID:
- 10042223
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Israel Journal of Chemistry
- Volume:
- 57
- Issue:
- 10-11
- ISSN:
- 0021-2148
- Page Range / eLocation ID:
- p. 1023-1031
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Calcium germanides with two mid‐late rare‐earth metals, Ca5−
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