Syntheses, Structural Characterization, and Kinetic Investigations of Metalla[3]triangulanes: Isoelectronic Nickel(0) and Copper(I) Complexes with Bicyclopropylidene (bcp) and Dicyclopropylacetylene (dcpa) as Ligands

The kinetics of the reactions between [Ni(bipy)(COD)] and bicyclopropylidene (bcp), dicyclopropylacetylene (dcpa) and 1,4‐dimethoxy‐2‐butyne (dmbu) were investigated using stopped‐flow techniques. Similar to previous studies the results support an associative mechanism (activation parameters for bcp: ΔH#=46±2 kJ ⋅ mol−1 and ΔS#=−69±8 J ⋅ mol−1 ⋅ K−1) and therefore allowed to postulate a more general reaction mechanism for the reaction pathway. The products, the nickel(0) complexes [Ni(bipy)(bcp)] and [Ni(bipy)(dcpa)], could be structurally characterized and the molecular structures are presented. In addition, the corresponding copper(I) complexes [Cu(bipy)(bcp)]PF6 and [Cu(bipy)(dcpa)]PF6 were also structurally characterized and their reactivity towards dioxygen was investigated. A detailed discussion of the structural properties and comparisons to similar literature‐known olefinic complexes with transition metals are presented.