DABCO is known for its strong interaction with neutral molecules possessing hydrogen-bond donors leading to adducts linked by hydrogen bonding in which the DABCO nitrogen acts as hydrogen bond acceptor.22,24-26 Interestingly, although in the compound [{(η5-C5H5)(CO)2Fe}2(µ-DABCO)](BF4)2, the nitrogen is not available for hydrogen bonding, it interacts strongly with the D2O and CH3COCH3 molecules. Thus, in crystals of compounds 1 and 2 packing is governed mainly by a set of strong and weak C-H...F intermolecular interactions (Table 3).