Carbonyl versus butadiene dissociation in binuclear butadiene cobalt carbonyls

► The butadiene derivatives (C4H6)Co2(CO)n (n = 6, 5, 4, 3, 2) have been investigated by density functional theory. ► Butadiene dissociation from (C4H6)2Co2(CO)4 is energetically favored over CO dissociation by ∼8 kcal/mol. ► The B3LYP method predicts essentially equal CO and butadiene dissociation energies from (C4H6)2Co2(CO)n (n = 3, 2).