Reactivity of an Arene Cobalt Triple Decker Complex Towards Various Ligands. Facile Arene Displacement in [Bis{( η⁵-pentamethylcyclopentadienyl)cobalt}-μ-{η⁴: η⁴-toluene}]

Photochemical Reactivity of Group 9 Metal Pinacolate Complexes

“…Given that this species appears to be formed only in benzene, it seems most likely that it is some sort of (Cp*Co) n (C 6 D 6 ) m arene adduct. However, while such complexes are well-known, they are either diamagnetic ,, or charged , species. The exact nature of the kinetic product thus remains unclear.…”

Development of more labile low electron count Co(i) sources: mild, catalytic functionalization of activated alkanes using a [(Cp*Co)2-μ-(η4:η4-arene)] complex

“…A family of Cp*Co arene complexes, containing a bridging arene, are known and have shown ready ligand displacement and subsequent reactivity with small molecules. 18,19 Moreover, exchange of the arene ligand with solvent in benzene-d 6 is observed at ambient temperature, via detectable monomeric Cp*Co(Z 6 -arene) complexes, suggesting facile access to Cp*Co(I) equivalents. 20 Though these compounds have found utility as building blocks in macromolecular chemistry, 21 the complexes have been relatively unexplored for catalytic applications.…”

“…23 Though 2 is competent for sp 3 C-H bond activation, we hoped to compare activity to other Co(I) sources. Two known complexes, Cp*Co(COD) 24 (11) and Cp*Co(Z 6 -C 6 Me 6 ) (12), 19 demonstrate no catalytic activity at 25 1C in a variety of solvents, though 12 does show product formation under more forcing conditions (470 1C in benzene). However, complex 3 does react with 4 at ambient temperature.…”

Cyclopentadienone-like Behavior of Fluorenone and 4,5-Diazafluoren-9-one

“…It is worth addressing the last point in more detail, since it turns out that 4 and 5 are quite unique in this context. All cyclopentadienylcobalt(I) arene complexes known so far belong to one of the following four categories: (A) mononuclear complexes of the electron-poor arenes C 6 (CF 3 ) 6 and C 6 (COOMe) 6 (although crystal structure determinations have not been reported for these types of compounds, there is no doubt that the arene shows η 4 coordination in each case); (B) mononuclear complexes of the electron-rich arene C 6 Me 6 16 (it is generally accepted that this ligand is always η 6 coordinated, although no reliable structural data have been reported); (C) mononuclear complexes of polycyclic aromatic hydrocarbons such as, for example, anthracene,16e decacyclene, and angular [3]phenylene (an η 4 coordination of a single six-membered ring is observed in each case); (D) oligonuclear complexes with bridging arene ligands (an antifacial η 4 :η 4 coordination of an arene ring is commonly observed here) . In view of these facts, an η 4 coordination of a single six-membered ring might have been expected for 4 and 5 .…”