Activation of alkynes by diphosphine- and µ-phosphido-spanned heterobimetallic complexes

DFT Mechanistic Insights into the Alkyne Insertion Reaction Affording Diiron μ-Vinyliminium Complexes and New Functionalization Pathways

“…Alkynes are useful and versatile reagents in organometallic chemistry. They can behave as η 2 terminal ligands or occupy bridging sites in polynuclear complexes, and this preliminary coordination may prelude to an impressive variety of reactions pathways . In particular, the intramolecular alkyne insertion into a metal–carbon bond, in di- and trinuclear metal complexes, represents an intriguing strategy to grow various hydrocarbyl fragments stabilized by bridging multisite coordination …”

Catalyzed M–C coupling reactions in the synthesis of σ-(pyridylethynyl)dicarbonylcyclopentadienyliron complexes

“…To reveal the mechanism of this process, an additional study is needed, since there are several possible reaction pathways for its proceeding. It is worth noting that the examples of the acetylene-to-vinylidene tautomerism involving two adjacent metal centers are known and described in several works, [66][67][68][69][70] but they are much less studied in contrast to the well-understood acetylene-tovinylidene rearrangement mediated by a single metal center. 71,72 It is also worth to note that the ortho-position of the nitrogen atom in 2-ethynylpyridine plays an important role in the process of formation of the binuclear FePd m-pyridylvinylidene complex 4, as the Pd-catalyzed reactions of Cp(CO) 2 FeI with 3-and 4-ethynylpyridines simply resulted in a decrease of yields of 2 and 3, and didn't give any binuclear products (Table 2 entries 9 and 13).…”

Crystal structure of {μ2-1,2-bis[(4-methylphenylsulfanyl]-3-oxoprop-1-ene-1,3-diyl-1:2κ2C3:C1}dicarbonyl-1κ2C-[μ2-methylenebis(diphenylphosphane)-1:2κ2P:P′](triphenylphosphane-2κP)ironplatinum(Fe—Pt), [(OC)2Fe(μ-dppm){μ-C(=O)C(4-MeC6H4SCH2)=CCH2SC6H4Me-4}Pt(PPh3)]

“…Related dicationic salts such as [(Co 2 (CO) 6 ) 2 -, 2 , 2 -(Me 2 S-CH 2 C CCH 2 S-Me 2 )][BF 4 ] 2 have also been described (Amouri et al, 2000). We and Shaw's group have demonstrated that upon treatment of the -carbonyl complex [(OC) 3 Fe(-dppm)(-CO)Pt-(PPh 3 )] with ArC CH (Ar = Ph, p-Tol, 2,4,5-trimethylphenyl, p-C 6 H 4 F, 2,4-C 6 H 3 F 2 , p-C 6 H 4 CF 3 ), dimetallacyclopentone complexes are formed, stemming from carbon-carbon coupling reactions between CO and the terminal alkyne (Fontaine et al, 1988;Jourdain et al, 2013;Knorr & Jourdain, 2017;Brieger et al, 2019). The first step involves the formation of a kinetic isomer [(OC) 2 Fe(-dppm){-C( O)C(H) C(Ar)}Pt(PPh 3 )], which then evolves to the thermodynamic one [(OC) 2 Fe(-dppm){-C( O)C(Ar) C(H)}Pt(PPh 3 )].…”