A Complete Triad of Zero‐Valent 17‐Electron Monoradicals of Group 7 Elements Stabilized by m‐Terphenyl Isocyanides

• Published in: Angewandte Chemie International Edition 2023-05, Vol.62 (19), p.e202300254-n/a
• Main Authors: Salsi, Federico, Wang, Shuai, Teutloff, Christian, Busse, Marvin, Neville, Michael L., Hagenbach, Adelheid, Bittl, Robert, Figueroa, Joshua S., Abram, Ulrich
• Format: Article
• Language: English
• Subjects: Carbonyl compounds; Carbonyls; Dimerization; Group 7 Elements; High-Field EPR; Ligands; m-Terphenyl Isocyanides; Manganese; Metalloradicals; Monoradicals; Rhenium; Rhenium isotopes; Technetium; Technetium compounds
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202300254

The first consistent series of mononuclear 17‐electron complexes of three Group 7 elements has been isolated in crystalline form and studied by X‐ray diffraction and spectroscopic methods. The paramagnetic compounds have a composition of [M0(CO)(CNp‐F‐ArDArF2)4] (M=Mn, Tc, Re; ArDArF2=2,6‐(3,5‐(CF3)2C6H3)2C6H2F) and are stabilized by four sterically encumbering isocyanides, which prevent the metalloradicals from dimerization. They have a square pyramidal structure with the carbonyl ligands as apexes. The frozen‐solution EPR spectra of the rhenium and technetium compounds are clearly anisotropic with large 99Tc and 185,187Re hyperfine interactions for one component. High‐field EPR (Q band and W band) has been applied for the elucidation of the EPR parameters of the manganese(0) complex. A series of structurally analogous monomeric manganese(0), technetium(0) and rhenium(0) monoradicals has been stabilized by means of sterically encumbered m‐terphenyl isocyanides. They possess square‐pyramidal structures. Their electron spin of S= 1/2 ${{ 1/2 }}$ allows the detection of resolved EPR spectra. High field EPR (Q band and W band) is shown to be a valuable tool for a complete analysis of the tensor components of the manganese compound.