Electron Deficient Compounds

Chemistry of the Carba-closo-dodecaborate(−) Anion, CB11H12-

“…1,2 One characteristic of electron-deficient structures is the aggregation of atoms to form 3-center-2-electron (3c2e) bonds, which typically results in formation of trigonal faces and hypercoordination. The high connectivity of atoms in a cluster compensates for the relatively low electron density in skeletal bonds.…”

13C nuclear magnetic resonance study of five- and six-coordinated carbon in nonclassical organometallic compounds: Dimeric trialkyl-, tricyclopropyl-, and triarylaluminums and some nido and closo carboranes

“…In many organometallic compounds, metal to carbon bonding cannot be explained on the basis of simple Lewis type covalent two-electron two-center bonding or ionic bonding (2)(3)(4)(5)(6). These molecules necessitate the involvement of two-electron threecenter (6)(7)(8)(9) or multicenter bonding and thus can be called "nonclassical" molecules (in accord with the definition of nonclassical carbocations used in organic chemistry) (2,(10)(11)(12)(13).…”

Chemical Reactions of Metal‐Metal Bonded Compounds of the Transition Elements

“…First row transition metal ions in their middle oxidation states rarely form strong metal-metal bonds. This is apparent in the chemistry of the Group b transition elements where, for oxidation number +3, molybdenum These considerations form the basis for Wade's rule (24,25,26). Closo …”