Electron Transfer Induced CS Bond Cleavage in Rhenium and Technetium Thioether Complexes: Structural and Chemical Evidence for π Back‐Donation to CS σ^* Orbitals

Abstract

The trends in carbon‐sulfur bond length for complexes of 1,4,7‐trithiacyclononane (9S3) provide compelling evidence that CS σ* orbitals accept π‐electron density from the metal. As the metal d‐orbital energy and occupancy increase, this leads ultimately to cleavage of the CS bonds with concomitant release of ethene in the Re and Tc complexes [Eq. (a)].

Push–Pull Molybdenum Trisdithiolenes Allow Rapid Nonconventional Binding of Ethylene at Ligand Sulfur Atoms

“…We expect that alkene dissociation from the alkene adduct of [Mo(tfd) 2 (bdt)] is facilitated by back donation of an occupied d orbital (likely d z 2) into the CÀS s* orbitals. [25] X-ray quality crystals of [Mo(tfd) 2 {bdt(CH 2 CH 2 )}] were grown by allowing ethylene to slowly diffuse into a toluene solution of [Mo(tfd) 2 (bdt)]. [21] Its structure provides the first example of a 2,3-dihydro-1,4-dithiin chelating to a transition metal using the sulfur atoms in the 1,4-positions ( Figure 3 [26] ).…”

B‐Substituted (Arene)ruthenacarborane–Sulfonium, –Thioether and–Mercaptan Complexes: Mild Single and Double Dealkylation and Structural Implications in the Antipodal Distance

“…[21] Thus, further dealkylation by C-S bond cleavage in the thioether B would follow liberation of a second equivalent of the halide and an exo-cluster S-bonded (thiolato)ruthenium intermediate like C could be formed (Scheme 3). Decoordination of the S-bonded thiolato complex C could then take place [22] thus forming the more stable (η 5 -C 2 B 3 )ruthenacarborane complex which becomes protonated to give the mercaptan complex.…”

Hybrid Car-Parrinello/Molecular Mechanics Modelling of Transition Metal Complexes: Structure, Dynamics and Reactivity

“…Hexathioether compounds [M(9S3) 2 ] n (where M are metals from Group 7 ± 12 of first, second and third row transition elements, 9S3 1,4,7-trithiacyclononane and n 1 ± 3) have been synthesized and characterized [28]. These systems exhibit interesting redox properties: Treatment of the doubly charged hexathioether complexes containing M Tc or Re with mild reducing agents such as ascorbic acid, Zn or SnCl 2 results in immediate carbon-sulfur bond cleavage and release of ethene.…”