Nance PJ, Thompson NB, Oyala PH, Peters JC. Zerovalent Rhodium and Iridium Silatranes Featuring Two-Center, Three-Electron Polar σ Bonds.
Angew Chem Int Ed Engl 2019;
58:6220-6224. [PMID:
30759317 DOI:
10.1002/anie.201814206]
[Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/26/2019] [Indexed: 12/19/2022]
Abstract
Species with 2-center, 3-electron (2c/3e- ) σ bonds are of interest owing to their fascinating electronic structures and potential for interesting reactivity patterns. Report here is the synthesis and characterization of a pair of zerovalent (d9 ) trigonal pyramidal Rh and Ir complexes that feature 2c/3e- σ bonds to the Si atom of a tripodal tris(phosphine)silatrane ligand. X-ray diffraction, continuous wave and pulse electron paramagnetic resonance, density-functional theory calculations, and reactivity studies have been used to characterize these electronically distinctive compounds. The data available highlight a 2c/3e- bonding framework with a σ*-SOMO of metal 4- or 5dz 2 parentage that is partially stabilized by significant mixing with Si (3pz ) and metal (5- or 6pz ) orbitals. Metal-ligand covalency thus buffers the expected destabilization of transition-metal (TM)-silyl σ*-orbitals by d-p mixing, affording well-characterized examples of TM-main group, and hence polar, 2c/3e- σ "half-bonds".
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