β Scribed by A. M. MEBEL; P. VON RAGUE SCHLEYER; K. NAJAFIAN; O. P. CHARKIN
No coin nor oath required. For personal study only.
Structure and Nonrigidity of B 9 H 9 2-and B 9 H 10 -. Comparison of BnHn 2-and BnH n+1 -Systems.
-Ab initio calculations at different levels indicate relatively high potential barriers for the intramolecular rearrangement of B 9 H 2-9 via the single diamond-square-diamond (DSD) or the double DSD mechanism. However, the open face-protonated form, B 9 H -10 , is highly fluctional. Facile rotation of the BH 2 group in B 9 H -10 with C 2v symmetry leads to a reversible opening of the boron cage from closo to nido. All BnH -n+1 species are fluxional, due to rapid proton migration. The proton affinities in the BnH 2-n series decrease with increasing size, since the Coulomb repulsion in the dianions becomes smaller and the coordination number at the protonation sites increases.
π SIMILAR VOLUMES
## Abstract A systematic search has allowed to find 196 valence structures (VS) 2β2βfor B~9~H and 728 for B~10~H instead of the 16 and 72 respectively described by Lipscomb^(1)^. With these numbers of valence structures, (NVS), valence structure indexes (VSI) 2β2β equal to 0.1637 and 0.1789 can be