1,3-Diboraheterocycles as ligands in metal complexes involving endo-C-H bonds

The involvement of endo-C-H bonds in the bonding of transition metal (2,3-dihydro-1,3-diborole) compounds is essential for their stabilization. It occurs predominantly via bridging C-H-B 3c,2e interactions, which activates the C-H bond regarding deprotonation and cleavage. In bis(1,3-diborole)nickel complexes with two endo-C-H bonds elimination of dihydrogen is observed at ambient temperature. Axial H-C-M bonding occurs in the slipped triple-decker [(Cp∗Ru)2(μ-C6B4H2Me8)].