BONDING IN CLUSTERS .11. GAS-PHASE PHOTOELECTRON-SPECTRA OF THE 12-APEX CLOSO SYSTEMS 1,12-B12H10(CO)2, 1,2-C2B10H12 AND 1,7-C2B10H12, AND RELATED MAIN GROUP-V AND GROUP-VI HETEROBORANES AND CARBORANES - THE ELECTRONIC-STRUCTURE OF B12H122-

The He I and He II photoelectron spectra of 1,12-B12H10(CO)2 and 1,2-and 1,7-C2B10H12 are assigned in terms of correspondence of bands to BH bonding or cluster-localized orbitals. The experimental assignments are found to agree excellently with MNDO calculations on the molecules, which allows assignment of the cluster orbitals and ionizations in terms of Stone's theory of closo-boranes. Spectra of the related closo-heteroboranes 1,2-X(CH)B10H10 (X = P, As, Sb), X2B10H10 (X = As, Sb), and SeBHH11 are found to be very similar, also agreeing with calculated results. The lone pairs of the heteroatoms are found to be localized in the valence s atomic orbital. An orbital diagram for B12H122− is extrapolated from these results, which shows it to be distinctly different from the smaller closo-borane anions. © 1990, American Chemical Society. All rights reserved.