Studies of Multicenter and Intermolecular Dihydrogen B-H•••H-C Bonding in [4,8,8-exo-{PPh3Cu}-4,8,8-(-H)3-commo-3,3-Co(1,2-C2B9H9)(1,2-C2B9H10)]

An experimentally based and theoretical electron density study of the title compound has been carried out, giving the first experimental description for the two types of bonding: between the transition metal (i.e., Co) and the dicarbollide dianions that occurs through the open C2B3 face of the nido-carborane and between the anionic commo cluster (i.e., Cobdc) and the transition metal (i.e., Cu) involving three unique (B-H)(3)Cu bonds. The Codicarbollide and CuCobdc bonds are shown to have a multicenter character, whereas direct CoCu interaction is found to be absent. The effect of the [Cu(PPH3)](+) association with the Cobdc anion on the Codicarbollide bonding is discussed. The description of intramolecular Codicarbollide and intermolecular B-HH-C connectivity in terms of the Hirshfeld approach and Voronoi tessellation is compared with the QTAIM results to confirm their qualitative and semiquantitative similarity.