Synthesis and molecular structure of the binuclear complex of chromium with a bridging bis-carbyne ligand

Ligand Redox Non‐Innocence in Transition‐Metal σ‐Alkynyl and Related Complexes

“…[106] In an interesting counterpoint, reduction of the group 6 alkynyl complexes [M(CϵCPh)(CO) 3 CpЈ] either chemically (Na/K, M = Cr, CpЈ = Cp) or electrochemically (M = Cr, CpЈ = Cp; M = Mo, W, CpЈ = Cp*) also affords bis-(carbyne) complexes [CpЈ(CO) 2 MϵC-C(Ph)=C(Ph)-CϵM(CO) 2 CpЈ], albeit in very low yields for the Mo and W examples, and is thought to occur by the sequence of reduction, CO elimination, C β -C β coupling and oxidation shown in Scheme 13. [107,108] The bis(carbyne) product undergoes two reversible reduction processes, separated by around 140 mV, although the electronic characteristics of the intermediate mono-anion have not been investigated in detail.…”

Electrocatalytic dimerisation of non-heteroatom-substituted manganese alkynylcarbene complexesElectronic supplementary information (ESI) available: details of syntheses and spectral characterisation of the new complexes, ORTEP plot of complex 3b. See http://www.rsc.org/suppdata/cc/b3/b300623a/

“…Yet, considering the reaction conditions in which the formation of 3 was initially observed (reducing reaction conditions, very low temperature vs. 120 °C for the rhenium analogs) and taking into account earlier observations by Ustynyuk et al of a Na/K-promoted dimerisation of acetylide complexes 5 and the recent report by Sierra et al, on the C 8 Kpromoted self-condensation-cycloisomerisation of group 6 alkynylcarbene complexes, 6 we reasoned that a radical process might also be effective here. § In an initial approach, complex 2a was reacted with readily available sodium benzophenone ketyl radical anion (NaBPK), in THF.…”

Synthesis and Characterization of Bimetallic Ruthenium Complexes Bridged with Linear C4H4and C6H4O2Ligands

“…The synthesis and characterization of bimetallic and polymeric organometallic compounds with π-conjugated bridges are attracting considerable interest. , During the past decades, a large number of conjugated organometallic bimetallic complexes with hydrocarbon chains serving as σ,σ-, σ,π-, or π,π-bound bridging ligands have been reported. Most of the conjugated organometallic bimetallic complexes with σ,σ-bridging hydrocarbon chains are those with metal−C(sp) linkages, for example, C x -bridged, , bis(acetylide), bis(carbyne), bis(vinylidene), and bis(allenylidene) complexes …”