Bonding analysis in inorganic transition-metal cubic clusters, 5 - M-8(mu(8)-E ')(mu(4)-E)(6)L-8 species centered and hexacapped by main-group atoms

The bonding in main-group atom-centered hexacapped transition-metal cubic c lusters M-8(mu(8)-E')(mu-E)(6)L-8 has been analyzed by means of density fun ctional theory (DFT) calculations. Although only one example of such compou nds has been characterized so far, DFT results indicate that it should be p ossible for other members of this family to be synthesized. As for their me tal-centered parents, there are several "magic" electron numbers that are a ble to satisfy the closed-shell requirement for such species, depending on the nature of the metal and the capping Ligands. The most probable cluster valence electron counts that imply significant M-M bonding are 120 and 122. The former value is favored when E' is an early main-group element while t he latter value is favored when E' is a late main-group element. Owing to t he high connectivity between the atoms, such a regular cubic architecture m ay also be observed with open-shell electron configurations, as observed fo r the 119-cluster-valence-electron fluster Ni-8(mu(8)-As)(mu(4)-As)(6)(PPh3 )(8).