RIGOROUS INTERPRETATION OF ELECTRONIC WAVE-FUNCTIONS .3. THEORETICAL CONFIRMATION OF A 3-CENTER, 2-ELECTRON C-H-C BOND IN THE IN-BICYCLO[4.4.4]TETRADECYL CATION

Ab initio quantum-mechanical calculations show that the D3 structure o f the in-bicyclo[4.4.4]tetradecyl (BCT) cation in which the bridging h ydrogen is located at the midpoint between two carbon atoms correspond s to an energy minimum, therefore confirming the presence of a symmetr ical three-center, two-electron C-H-C bond. This conclusion is further reinforced by the agreement between the calculated and the experiment al IR and NMR spectra. Bonding in the BCT cation is rigorously represe nted by a set of 40 valence localized orbitals that fall into 8 distin ct classes. The C-H-C bond is described by a single localized orbital, giving rise to the C-H covalent bond order of 0.504 and a negative ch arge of -0.228 on the bridging hydrogen.