Syntheses, structures and electrochemical properties of homoleptic ruthenium(III) and osmium(III) complexes bearing two tris(carbene)borate ligands

Distortion Pathways of Transition Metal Coordination Polyhedra Induced by Chelating Topology

“…A handful of compounds with two related claw ligands in which the pyrazol rings of TpB are replaced by N-heterocyclic carbenes also present small distortions of the octahedron along the elongated trigonal prism path (between 3 and 7%) and right along the path (path deviations of 0.2% at most). − Similarly, a few complexes with two tridentate RC­(CH 2 PR 2 ) 3 claw ligands present twist-elongated structures with up to 31% distortions toward the elongated trigonal prism. − …”

Base-free synthesis of benchtop stable Ru(iii)–NHC complexes from RuCl3·3H2O and their use as precursors for Ru(ii)–NHC complexes

“…These complexes were found to be air and moisture stable and can be stored under benchtop conditions for several months with no sign of decay. Furthermore, these complexes enrich the list of very rare Ru( iii )–NHC complexes, 42–44 which have, so far, been obtained by oxidising a Ru( ii )–NHC complex as the Ru( ii ) precursor. 41 To check the usefulness of 1a–c as starting materials for the preparation of Ru( ii )–NHC complexes with different ancillary ligands, complexes 1a–c have been used to prepare the phosphine complexes 2a–c following the same procedure as that used for the preparation of RuCl 2 (PPh 3 ) 3 from RuCl 3 ·3H 2 O.…”

“…7 During our investigation, we noticed that even after a few decades of research in this field, a suitable Ru complex with an NHC ligand, which can be used as a precursor for the synthesis of new complexes with other co-ligands, is unavailable. Furthermore, it is surprising to note that until now, only four examples of Ru( iii )–NHC complexes 41–44 have been reported (Fig. 1), all of which were obtained upon oxidation of their Ru( ii )–NHC analogues.…”

Heteroleptic and Homoleptic Iron(III) Complexes with a Tris(N‐Heterocyclic Carbene) Borate Ligand: Synthesis, Characterization, and Catalytic Application

“…Interestingly, the high electron-donating ability of Tim R allows the isolation of highvalent species like Fe(IV)-nitrido, [14] Fe(V)-nitrido, [15] Co(III)oxido [16] , and Ni(III) 2 (μ-1,2-peroxo) [17] . On the other hand, by employing a less sterically hindered methyl group, homoleptic complexes bearing two Tim Me ligands have been synthesized and characterized for Mn(III), [18] Fe(III), [19] Co(III), [20] Mn(IV), [10] Fe(IV), [21] Ru(III), [22] and Os(III) [22] ions. Since the two Tim Me ligands lead to strong ligand-field splitting and steric rigidity, [Fe III -(Tim Me ) 2 ] + are known to have long-lived photoexcited states (2 ns), [19] which is quite rare for an iron complex.…”