Isomers of B₂₀H₂₆: structural characterisation by X-ray diffraction of 2,2′-Bi(nido-decaboranyl)

Abstract

One of the isomers of B,,H,, obtained by the photolysis of B,,Hl, has been shown by single-crystal Xray structure analysis to be 2,2'-bi(nido-decaboranyl).A NUMBER of isomers of bi(nido-decaboranyl), (B1,,H&,, have been isolated.lS2 However, only for one of these has it been possible to infer the structure by indirect methods,Z

Transition-metal-promoted reactions of boron hydrides. 6. Platinum(II) bromide catalyzed borane and carborane dehydrodimerization reactions: a new synthetic route to boron-boron linked multicage boranes and carboranes

“…Reductive-elimination of the platinum(IV) intermediate would then yield the observed product, 1:2'-[B5H8]2, and the formation of an [HPtBr] species which could react with HBr, completing the catalytic cycle, to give PtBr2 and hydrogen. (13) The selective formation of the 1:2'-[B5H8]2 isomer is consistent with the mechanism outlined above and indicates that the PtBr2 has a dual function in these reactions. The initial electrophilic substitution at the apex, however, appears to be the key step in the pentaborane(9) reaction, since it was found that when the apex position was blocked with a methyl substituent no reaction with PtBr2 occurred.…”

Electronic Requirements for Macropolyhedral Boranes

“…There are a set of isomers consisting of two B 10 H 14 units connected by a 2c−2e bond. Of the 11 possible geometrical isomers, 7 isomers have been structurally characterized by NMR spectroscopy. − Four among these are confirmed by single-structure X-ray studies. Here, n = 20, m = 2, and p = 2, and hence, the molecule requires 24 electron pairs.…”

Notes. Synthesis, crystal structure and gas-phase photoelectron spectroscopic study of B,B′-bis(1,3-dicyclohexyl-1,3,2-diazaborolidin-2-yl)

“…For B2F4 and B2C14 the values for the gas phase and solid state were 1.720 and 1.67 and 1.702 and 1.75 A respectively.' The mean distances B-N 1.393 (7), C-N 1.454 (6), and C-C 1.494(9) A in compound (1) are unexceptional (Table 1) and agree well with the corresponding bond lengths reported for (I; R = Me) [mean B-N 1.413 (8), mean ring C-N 1.461 (7) but the N components of (111) can n donate to the nominally empty B 2p orbital. The interaction of these two systems across the B-B bond depends on the interplanar angle (€I), and as 0 approaches 0" a splitting of the energies of the ll, and 112 orbitals4 arising from (111) would be expected.…”