From 0 to II in One‐Electron Steps: A Series of Ruthenium Complexes Supported by TropPPh₂

Abstract

We report the synthesis of a series of ruthenium complexes supported by the phosphine olefin ligand tropPPh2 (trop=5-H-dibenzo-[a,d]cyclohepten-5-yl) in the oxidation states 0, +I, and +II, formed via successive one-electron oxidization steps from Ru(0) (tropPPh2 )2 . The bidentate character of the tropPPh2 ligand and its steric hindrance force the complexes to adopt uncommon geometries, which were investigated by X-ray diffraction analysis. EPR data of the mononuclear Ru(I) complex reveal couplings of the unpaired spin with the ruthenium and two phosphorus nuclei, as well as the olefinic protons which show that the spin is mainly localized on the Ru(I) center.

Metalloradical Reactivity of RuI and Ru0 Stabilized by an Indole‐Based Tripodal Tetraphosphine Ligand

“…Recently, the group of Grützmacher reported the remarkable 4‐coordinate 15‐electron complex [Ru I (tropPPh 2 ) 2 ]BF 4 featuring two bidentate tropPPh 2 ligands (trop=5 H ‐dibenzo[ a,d ]cyclohepten‐5‐yl)). Besides Ru I , this ligand scaffold stabilizes ruthenium complexes in oxidation states ranging from Ru 0 to Ru II . No further reactivity with this complex has been reported to date.…”

“…Besides Ru I ,t his ligand scaffold stabilizes ruthenium complexes in oxidation states ranging from Ru 0 to Ru II . [5] No further reactivity with this complex has been reported to date.…”

“…The t-value of 0.70 confirms ag eometry in-between at rigonal bipyramid and as quare pyramid. [11] The one-electronr eduction of 2 to 3 is accompanied by the loss of one chlorido ligand and shortening of most of the RuÀPb onds (Ru-P1 = 2.2940 (12);R u-P2 = 2.2930(12) )a nd decrease of the ]P1-Ru-P2 angle to 134.84 (5)8 (See the Supporting Information, Ta ble S1).…”

Synthesis, Isolation, and Characterization of Two Cationic Organobismuth(II) Pincer Complexes Relevant in Radical Redox Chemistry

“…Characterization of intermediates in chemical processes is of paramount importance to understand and improve their performance. In particular, isolation of paramagnetic complexes involved in single electron transfer (SET) redox events is an arduous task, especially for main group elements, due to their high reactivity . Bismuth redox catalysis has recently emerged as a versatile platform based on a single p-block element, for which both two- and one-electron (SET) redox cycles are within reach. , The latter represents a unique reactivity paradigm for a main group element, opening up unusual pathways for organic synthesis.…”

Hydrogenolysis of Polysilanes Catalyzed by Low‐Valent Nickel Complexes

“…Spectroscopic studies suggested that two diamagnetic hydrido–nickel complexes, 5 a and 6 a , participate in the catalytic cycle. Both complexes contain the diolefin‐amine trop 2 NH, which has remarkable properties as stabilizing ligand for low‐valent metal complexes . We could, therefore, isolate such low‐valent nickel hydrides and characterize them structurally.…”