Interaction of cyclic thiadiynes with CpCo(COD)—selectivity and reactivity

Selected recent developments in organo-cobalt chemistry

“…The mechanism by which the two types of product are made has been examined. 93 A number of cyclic thiadiynes containing a sulfur moiety in the propargylic position with respect to both triple bonds were reacted with CoCp(COD). The sulfur atom was expected to stabilize the intermediate metallacycles 264 and 265, Scheme 69.…”

“…The stability of these intermediates depends mostly on the sulfur-cobalt interaction, and any steric hindrance that might arise in the transition states. 93 Gleiter and co-workers were unable to analyse intermediates 264 and 265 due to their instability. The geometry of non-sulfur containing analogues in the transition state was correlated with the triple bond distances of their respective starting materials, and compared to those compounds containing sulfur.…”

“…As stated above, 274 reacts with diphenylacetylene to give the 18-electron cobaltacycle 277, and then reductive elimination occurs giving ring closure to yield the cyclobutadiene Scheme 69 Attempted synthesis of sulfur containing cobalt cyclobutadiene complexes from thiadiynes. 93 Scheme 70 Synthesis of sulfur containing cobalt cyclobutadiene complexes from thiadiynes. 93 Scheme 71 Synthesis of CoCl(PPh 3 ) 3 .…”

Chalcogen Bonding Induced Tetraselenides from Twisted Diselenides

“…Several examples have been reported with one of these interactions, while the co‐existence of both type I and type II interactions are rare. For example, Gleiter et al reported the ring systems with alkane units between chalcogen centers to demonstrate the co‐existence of both types I and II interactions in 1‐thiacyclododeca‐3,10‐diyne ,. [3a] Subsequently, similar such ring systems based on selenium were identified and compared.…”

“…[3a] Subsequently, similar such ring systems based on selenium were identified and compared. [10b], , [3a] However, the type I and type II interactions are not observed with σ donor and π accepting type of ligands such as imidazole or triazole supported selenium moieties due to the rigid structure with bulky N‐substituents. Herein we address this intriguing aftermath and describe unprecedented cationic selenide systems and its tunable self‐assemblies through chalcogen–chalcogen interactions.…”