Synthesis of small nido-ferrapentaboranes; a novel borane-capped nido-diferrapentaborane

Abstract

Pentaborane(9) reacts with(2) in yields of up t o 1 and 22% respectively; the X-ray crystal structure of (1) shows a nido-pentaborane(9) structure in which a BH3 fragment caps the Fe2B face.

Reactions of pentaborane(9) with electron-rich molybdenum and tungsten phosphine polyhydrides

“…Otherwise each boron nuclei correlated correctly to its respective terminal proton and bridge protons where appropriate. B (6) showed correlations only with its W-H-B bridge.…”

“…The most surprising feature of the structure is the presence of an edge-bridging {BH 3 } unit [atom B (6)] which substitutes for one of the bridge hydrogen atoms between the metal and one of the basal boron atoms B(5). One of the hydrogen atoms on this {BH 3 } unit is bridging between (B6) and the metal, with the other two terminal hydrogen atoms exo and endo on this boron.…”

“…1). The metallaborane ''MB 4 H 8 '' cage in (1) is known for a number of transition metals including tantalum [11], tungsten [7,12,25], iron [6] and cobalt [13]. The 11 B NMR spectrum of (1) consists of three resonances of relative intensity 1:2:1.…”

“…We are exploring the reaction of pentaborane (9) with electron-rich transition-metal compounds. For example, the reaction of pentaborane (9) with [Fe(PMe 3 [6]. We have also reported the reaction of the tungsten complex [W(PMe 3 ) 3 H 6 ] with metallaboranes to give novel metallaborane clusters [7,8].…”

Partial incorporation of a cyclopentadienyl ligand into a molybdaborane to form a molybdacarbaborane

“…We have been interested in exploring the formation and chemistry of metallaboranes of the early to middle transition metals [14][15][16][17][18]. In particular, we have been able to synthesise the molybdaborane arachno-2-[Mo(g-C 5 H 5 )(g 5 :g 1 -C 5 H 4 )B 4 H 7 ] (I) in gram quantities and this has permitted a study of its chemistry [19].…”