Palladium-catalyzed oxidative homocoupling of pyrazole boronic esters to access versatile bipyrazoles and the flexible metal–organic framework Co(4,4′-bipyrazolate)

A facile route to 4,4'-bipyrazole (H2bpz) and other symmetric bipyrazoles is achieved via the palladium-catalyzed homocoupling of a pyrazole boronic ester in the presence of air and water, enabling us to provide the first crystal structures and evidence of structural phase changes in the bipyrazolate-based metal-organic framework Co(bpz).