Structure and Properties of HFe3(CO)9BH3R and the Conjugate Bases - (R = H and CH3). Inorganometallic Analogues of Hydrocarbyltriiron Clusters

Article abstract of DOI:10.1021/ja00272a026

The ferraboranes (μ-H)Fe3(CO)9BH3R and the conjugate bases <(μ-H)Fe3(CO)9BH2R>^-, R = H and CH3, have been prepared and characterized.Crystals of HFe3(CO)9BH4 form in the space group <*> with unit cell parameters a = 8.823 (5) Angstroem, b = 11.523 (5) Angstroem, c = 7.850 (4) Angstroem, α = 98.89 (4) deg, β = 109.82 (4) deg, γ = 87.92 (4) deg, V = 741.7 Angstroem³, and Z = 2.The structure was solved by direct methods and refined to R = 0.061 and R_w = 0.079 for 2157 independent 0 >/= 3?(F₀)> reflections.The infrared spectra and 11B NMR and dynamic 1H NMR spectra have been measured for all compounds.Mass spectra and UV-vis spectra are reported for the neutral compounds while the Moessbauer spectrum is reported for one anion (R = H).The neutral compounds can be considered as formal <μ3-BH3R> triiron clusters.Both the neutral and anionic ferraboranes are isoelectronic with the hydrocarbyliron clusters (μ-H)3Fe3(CO)9(μ3-CR), R = H and CH3, and the ferraborane anions are isoprotonic with the hydrocarbyls.As such the ferraboranes are inorganometallic analogues of the organometallic clusters.Among other things, a comparison of these clusters yields insight into the factors important in determining stable hydrogen positions on these tetranuclear systems.