Stability of polyhedral borane anions and carboranes

Jemmis, E. D. ; Pavankumar, P. N. V. (1984) Stability of polyhedral borane anions and carboranes Proceedings of the Indian Academy of Sciences - Chemical Sciences, 93 (3). pp. 479-489. ISSN 0253-4134

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Official URL: http://www.ias.ac.in/j_archive/chemsci/93/7/479-48...

Related URL: http://dx.doi.org/10.1007/BF02840533

Abstract

Polyhedral borane anions and carboranes that can be constructed formally from the interaction of rings and caps will be stable with six interstitial electrons. Interstitial electron count is obtained by summing the number of π electrons of the ring and the electrons of the caps involved in ring cap binding. Thus B7H7-2 (D5h) has 6 interstitial electrons (none from the B5H5 ring, two each from the twobh caps and two negative charge),mndo calculations on isoelectronic pyramidal molecules B6H6-4 (C5v), B5H5CH-3 (C5v), B5H5-4 (C4v), B4H4CH-3 (C4v), B4H4 -4 (Td) and B3H3CH-3 (C3v) suggests a criterion based on the out-of-plane bendings of the ring B-H bonds to select the best combination of borocycles and BH or CH caps. Three-membered borocycle prefers CH cap, five-membered borocycle prefers BH cap. The preference of four-membered ring for BH or CH cap is not as pronounced. The extra stability of B12H12-2 arises from the geometry of the icosahedron. The relative stabilities ofnido andcloso carboranes follow from these rules.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Polyhedral Borane Anion; Carboranes; Overlap Matching
ID Code:13579
Deposited On:12 Nov 2010 15:18
Last Modified:16 May 2016 22:43

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