Post-synthetic modification of a porous hydrocarbon cage to give a discrete Co24 organometallic complex

A new alkyne-based hydrocarbon cage was synthesized in high overall yield using alkyne–alkyne coupling in the cage forming step. The cage is porous and displays a moderately high BET surface area (546 m2 g–1). The cage loses crystallinity on activation and thus is porous in its amorphous form, while very similar cages have been either non-porous, or retained crystallinity on activation. Reaction of the cage with Co2(CO)8 results in exhaustive metalation of its 12 alkyne groups to give the Co24(CO)72 adduct of the cage in good yield.