Propene complexes of molybdenum and tungsten stabilized by intramolecular coordination of the 1-(quinol-8-yl)indenyl ligand

Abstract

Synthesis, reactivity and properties of unusually stable propene complexes of molybdenum and tungsten are reported.

Stabilization of propene molybdenum and tungsten half–sandwich complexes by intramolecular coordination of a thioether function

“…A tungsten complex, presented in Scheme 1 (reaction B), was found to be stable up to 0 °C. 21 This study further documented that the h 2 -propene ligand, in this type of complex, can be easily…”

Cyclopentadienyl‐Based Anticancer Drugs: Improvement of Cytotoxic Activity through Functionalisation of the π Ligand

“…Numerous of cyclopentadienyls containing either primary, [45] secondary, [46] tertiary [39,47] or aromatic amine [48–50] functional groups in the side chain were reported in the literature. However, in many cases pronounced tendency to form strong intramolecular N→M interaction with metal atom was found.…”

“…Although this synthetic procedure was previously used for preparation of a wide range of Cp‐allyl compounds, the reported yields are rather moderate (typically ∼60 %) [38,48] . For complexes 4 and 5 , the anomalously high yield is related to isolation and purification of organolithium reagents 3 and 4 , leading to increased conversion to target complexes 5 and 6 .…”

“…Recently, the η 2 ‐propene complexes of molybdenum and tungsten were unambiguously proved as products of the protonation reaction [48] . However, the η 2 ‐bonded propene is readily exchanged either by acetonitrile or by weakly bonded dimethyl sulfide [48] . Although for 5 and 6 , the protonation of allyl with HBF 4 ⋅ Et 2 O takes place, the reactivity toward strong acid is further affected by the presence of amine moiety in the side chain of Cp ligand.…”

“…For the complexes of the type [(η 3 ‐allyl)(η 5 ‐Cp′)M(CO) 2 ], where Cp′ is cyclopentadienyl and its congeners, the reaction with strong acid leads to the formation of unsaturated propene [55] . Recently, the η 2 ‐propene complexes of molybdenum and tungsten were unambiguously proved as products of the protonation reaction [48] . However, the η 2 ‐bonded propene is readily exchanged either by acetonitrile or by weakly bonded dimethyl sulfide [48] .…”