Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

Abstract

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

The Additive Nature of Energy Penalties in 10‐Vertex nido‐(Car)boranes

“…Experimentally known [14] nido-6-[CB 9 H 12 ] -(FA, Figure 4) has two structural features, HH and 3kC(H), each once. Both FB and FC have the carbon atom at vertex number 5 (C 3kǞ4k ), but different hydrogen positions result in one HH (two adjacent hydrogen bridges) in the former and H(C)H (a carbon atom between two hydrogen bridges) in the latter.…”

Metallacarborane chemistry of the hypho-[6,7-C2B6H13]− anion: the formation of uniquely structured metallacarboranes [5-Cp∗-arachno-5Londesborough1, Janoušek2, Štı́br3 et al. 2004Journal of Organometallic Chemistry120110View full textAdd to dashboardCite

“…Fig. 3 is an ORTEP representation of the crystallographically determined structure of compound 3, which displays the same nine-vertex nido molecular geometry as the previously reported nido-1-CB 8 H 12 monocarbaborane (compound 5, for new numbering see Scheme 3) [7]. As far as we are aware, this geometry has not previously been observed in metallacarborane chemistry.…”

“…Simplified scheme for the formation of 4, (2) and ½2; 5-Cp à 2 -10-Me-nido-2; 5; 1-Rh 2 CB 6 H 9 (3) from anion 1. (2), 4,6-C 2 B 7 H 13 (4, data from [5]), Cp à 2 Rh 2 CB 6 H 9 ðCH 3 Þ (3), and 1-CB 8 H 12 (5, data from [7]). Scheme 1.…”

Metallacarborane chemistry of the hypho-[6,7-C2B6H13]− anion: Reaction with nickelocene and the formation of three multimetallic nickel–boron clusters

“…Nevertheless, both isomers share a cluster structure that may be derived from a tricapped trigonal prism by elongation of the Ni7-B9 polyhedral edge. This is an unusual nido configuration that is, in this case, strangely favoured to that derived from the elongation of two edges (such as Ni7-B3 and Ni7-B4) to generate a five-membered open face: a geometry adopted by the majority of nido nine-vertex species [3,[7][8][9][10]. Confirmation of the isomeric nature of compounds (2) of (3) is also in the ready conversion of (3) into (2) on heating in boiling toluene.…”