40855-92-3Relevant academic research and scientific papers
Structure and spectra of 4,5-μ-tetracarbonyliron-hexaborane(10), Fe(CO)4B6H10, and its conjugate base, [Fe(CO)4B6H9]-
Srivastava, Dileep K.,Rath, Nigam P.,Barton, Lawrence,Ragaini, James D.,Hollander, Orin,Godfroid, Robert,Shore, Sheldon G.
, p. 2017 - 2024 (2008/10/08)
The chemistry of B6H10Fe(CO)4 (I) and its conjugate base [B6H9Fe(CO)4]- (II) has been extended. 11B and 1H NMR spectra and the crystal and molecular structure of I are reported. I crystallizes in the orthorhombic space group Pbca, with a = 11.441(3) ?, b = 11.696(4) ?, c = 16.396(3) ?, and Z = 8. The crystal structure determination of this air-sensitive species indicates that the cage geometry is not substantially different from that of the parent borane. The position of the Fe atom is well below the basal B5 plane, the dihedral angle being 55.7°. The angles around the Fe atom suggest trigonal-bipyramidal geometry with the axial Fe-C bond diverging from linearity by ca. 6°. I is readily deprotonated with KH to afford the conjugate base [B6H9Fe(CO)4]- (II). Variable-temperature NMR spectra for II indicate complex dynamic processes, and the data are interpreted in terms of fluxional motion of the bridging H atoms, which is quenched at ca. -130°C, and also of the borane cage relative to the Fe(CO)4 moiety, which is quenched at ca. -10°C. Two processes are identifed for the former: complete scrambling of the three bridging H atoms among the four available sites above -50°C and a process that is partially quenched in which only one H atom moves above -100°C.
