91032-15-4Relevant academic research and scientific papers
Metal atom synthesis of metallaboron clusters. 4. Direct synthesis of (η6-arene)ferracarborane clusters from alkynes and boranes. Structural characterization of the four-carbon (η6-arene)metallacarboranes 1-[η6-C6(CH3) 6]Fe-4,5,7,8-(CH3)4C4B ...
Micciche, Robert P.,Briguglio, James J.,Sneddon, Larry G.
, p. 1396 - 1402 (2008/10/08)
Full title: Metal atom synthesis of metallaboron clusters. 4. Direct synthesis of (η6-arene)ferracarborane clusters from alkynes and boranes. Structural characterization of the four-carbon (η6-arene)metallacarboranes 1-[η6-C6(CH3) 6]Fe-4,5,7,8-(CH3)4C4B 3H3 and 2-[η6-CH3C6H 5]Fe-6,7,9,10-(CH3)4C4B 5H5. The reaction of thermally generated iron atoms with pentaborane(9), toluene, and 2-butyne was found to yield as the major product the (π-arene)ferracarborane sandwich complex 1-[η6-C6(CH3)6]Fe-2,3-(CH 3)2C2B4H4, I, along with smaller amounts of the four-carbon metallacarborane complexes 1-[η6-C6-(CH3) 6]Fe-4,5,7,8-(CH3)4C4B 3H3, II, 1-[η6-CH3C6H 5]Fe-4,5,7,8-(CH3)4C4B 3H3, III, and 2-[η6-CH3C6H 5]Fe-6,7,9,10-(CH3)4C4B 5H5, IV. Reactions carried out in the absence of toluene also yielded I and II but in reduced yields. The structures of II and IV were determined by single-crystal determinations. Compound II was shown to have an arachno-type cage geometry derived from a bicapped-square antiprism missing two vertices, with the iron atom occupying the five-coordinate 1-position in the cage and the four carbons occupying positions on the open face of the cage. An unusually short carbon-carbon bond distance of 1.367 (4) A? was observed for the non-metal-bonded carbons in the cage and is thought to result from localized multiple bond character between these carbons. Crystal data for II: space group P21/c, Z = 4, a = 8.753 (3) A?, b = 10.190 (2) A?, c = 22.118 (3) A?, β = 95.08 (2)°, V = 1965 A?3. The structure was refined by full-matrix least squares to a final R of 0.060 and Rw = 0.066 for the 2597 unique reflections which had Fo2 > 3σ(Fo2). Compound IV was shown to be an analogue of decaborane(14) in which the iron atom occupies the five-coordinate 2-position in the cage and the carbon atoms occupy the 6,7- and 9,10-positions on the open face. Crystal data for IV: space group P1?, Z = 2, a = 9.368 (5) A?, b = 11.399 (4) A?, c = 8.708 (4) A?, α = 90.84 (4)°, β = 116.51 (5)°, γ = 94.03 (4)°, V = 829 A?3. The structure was refined by full-matrix least squares to a final R of 0.074 and Rw = 0.065 for the 760 unique reflections which had Fo2 > 3σ(Fo2). The iron to arene bonding in both II and IV appears normal and is consistent with a symmetrical η6-coordination. Reactions of iron atoms with hexaborane(10), toluene, and 2-butyne were also found to give low yields of compounds I, II, and III.
