Synthesis, Characterization, and Ligand Substitution of [HFe₄(CO)₁₂BH]-: An Isoelectronic and Isoprotonic Inorganometallic Analogue of Hfe₄(CO)₁₂CH
The anion [HFe4(CO)12BH]- has been prepared by the deprotonation of HFe4(CO)12BH2 and by the reaction of [HFe3(CO)9BH3]- with Fe2(CO)9. The latter constitutes an example of a high yield cluster expansion reaction that occurs with the concurrent production of Fe(CO)5 and H2. The most stable hydrogen locations on [HFe4(CO)12BH]- are analogous to those on the isoelectronic HFe4(CO)12CH molecule; however, hydrogen mobility on the cluster framework is more facile for the ferraborane than for the hydrocarbon analogue. Substitution of CO by PPhMe2 on [HFe4(CO)12BH]- occurs cleanly on a “wing-tip” iron via a second-order process involving a transient intermediate containing PPhMe2. Endo-hydrogen position is unaffected by monosubstitution, but the energy barrier associated with hydrogen exchange is increased. Replacement of a second CO by phosphine on the other “wing-tip” iron proceeds more slowly and results in the conversion of the FeHFe into a FeHB interaction, thereby producing a coordinated BH2 fragment. The effects that B-/C and CO/PPhMe2 interchanges have on stable hydrogen position and on endo-hydrogen mobilities are discussed within the framework of extended Hückel calculations. © 1987 American Chemical Society.
C. E. Housecroft et al., "Synthesis, Characterization, and Ligand Substitution of [HFe₄(CO)₁₂BH]-: An Isoelectronic and Isoprotonic Inorganometallic Analogue of Hfe₄(CO)₁₂CH," Journal of the American Chemical Society, American Chemical Society (ACS), Jan 1987.
The definitive version is available at http://dx.doi.org/10.1021/ja00245a023
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© 1987 American Chemical Society (ACS), All rights reserved.