Missing Hydrogens in B₁₉H₂₀^-? Application of Electron Counting Rule for Edge-Sharing Macropolyhedral Boranes

Abstract

According to the n + m electron counting rule for condensed polyhedral boranes (Balakrishnarajan, M. M.; Jemmis, E. D. J. Am. Chem. Soc. 2000, 122, 4516.), an edge-shared bis-nido structure with a B19 skeleton requires 23 electron pairs for skeletal bonding (19 + 2 + 2 for bis-nido arrangement). B19H20 reported recently (Dopke, J. A.; Powell, D. R.; Gaines, D. F. Inorg. Chem. 2000, 39, 463.) lacks two electrons. We propose that the observed structure has the molecular formula B19H22 -. The geometry of B19H20 3- based on the calculations at the B3LYP/6-31G* level is given here.

Borane Polyhedra as Building Blocks for Unknown but Potentially Isolatable New Molecules – Extensions based on Computations of the Known B18H22 Isomers

“…As for the five B 18 H 22 isomers, the known syn-B 18 H 22 and anti-B 18 H 22 isomers were dealt with in one of the original papers on the mno concept, 44 and the two additional isomers 3 and 4 follow entirely the same reasoning. For the fifth isomer, 5, m = 3, n = 18, o = 0, and p = 3 (nido), giving 24 electron pairs as the mno sum.…”

3 Boron

“…9 These electron counting rules have been used to determine that the previously reported macropolyhedral borane [B 19 H 20 ] Ϫ should be reformulated as [B 19 H 22 ] Ϫ . 10 A theoretical study of the icosahedral closo-borane dianions [B 12 H 12 ] 2Ϫ with endohedral noble gas atoms (Ng = He, Ne, Ar, and Kr) and their lithium salts (Li[Ng@B 12 H 12 ] Ϫ and Li 2 [Ng@B 12 H 12 ]) has been described. 11 The distortions from octahedral symmetry that occur in hypoelectronic 6-vertex polyhedral clusters of the Group 13 elements (including boron) have been studied by DFT methods.…”

Formation of new nickel-containing nineteen-vertex metallaborane clusters prepared from the anti-B18H22 borane cluster: molecular structures of [Ni(THF)4(H2O)2][B18H20Ni(η5-C5H5)]2 and [B18H19(2-THF)Ni(η5-C5H5)]

“…A saturated aqueous solution of tetramethylammonium chloride was added until no more solid precipitated. The solid was filtered off, dried, and pure product [ 11 B, and 13 C), IR, elemental analysis and electronic spectral data for compounds 1a and 1b are given in Tables 1 and 2. Crystallographic and structural data for compound 1a are given in Tables 3 and 4.…”

“…Sneath and Todd reported the synthesis of several nineteenvertex metallaborane compounds based on both the anti-and † Electronic supplementary information (ESI) available: 11 isomer include nineteen-vertex transition metal species with nickel, cobalt, palladium, and rhodium incorporated into the macropolyhedral framework. These compounds were synthesized using a general pathway involving the initial deprotonation of the B 18 H 22 cage to form the [B 18 H 20 ] 2Ϫ species, usually with sodium hydride, followed by reaction with a suitable organometallic reagent to produce the nineteen-vertex metallaborane, typically in yields of less than 35%.…”