Routes to Compounds Containing M−B Bonds. Reaction of [Cp*FeH₂]₂ with BH₃·THF, Yielding the Hydrogen-Rich arachno-Ferrapentaborane 1-Cp*FeB₄H₁₁ (Cp* = η⁵-C₅Me₅)

Abstract

The reaction of [Cp*FeH 2 ] 2 (Cp* ) η 5 -C 5 Me 5 ) with BH 3 ‚THF under mild conditions produces the new arachno-ferraborane 1-Cp*FeB 4 H 11 via a boraallyl intermediate. Reaction of 1-Cp*FeB 4 H 11 with Co 2 (CO) 8 yields the novel nido-dimetallahexaborane 1,2-(Cp*Fe)-{Co(CO) 3 }B 4 H 8 , which has been characterized by an X-ray diffraction structure determination.

The Bonding Situation in the Dinuclear Tetra-Hydrido Complex [{5CpFe}2(μ-H)4] Revisited by Hard X-Ray Spectroscopy

“…13 In contrast, due to the large scattering length of 2 H, neutron diffraction is a powerful technique but requires selective deuteration. In the same sense, Mossbauer spectroscopy may require enrichment of the sample with 57 Fe. 14,15 1 H NMR spectroscopy is well suited only for the investigation of diamagnetic transition metal hydrides.…”

“…16,17 But it can be challenging if the bands of the investigated compounds are forbidden or overlapping with ligand, solvent, or coreactant vibrations. 57 Fe nuclear resonance vibrational spectroscopy (NRVS) is able to overcome the limitations of conventional vibrational spectroscopy. The intensity of NRVS spectra is only sensitive to 57 Fe nuclear motion and is therefore able to detect signals in spectral regions that would be otherwise superimposed by other vibrational modes in conventional vibrational spectroscopy.…”

Reactivity studies on [Cp′FeI]2: From iron hydrides to P4-activation

“…19 Hence, iron hydrides might be an intriguing starting material for this transformation. The only example of an iron polyhydride cluster supported exclusively by cyclopentadienyl ligands is [(C 5 Me 5 ) FeH 2 ] 2 (prepared from (C 5 Me 5 )FeCl(tmeda) and LiAlH 4 ), 20 which exhibits a rich reaction chemistry with borane, 21,22 silanes 20,23 and phosphines. 20 However, the use of sterically demanding ligands such as Cp 0 can alter reactivity patterns significantly as previously shown for other metals.…”

Formation of ferraboranes from pentaborane(9) or BH3·thf and an electron-rich cyclopentadienyl iron phosphine hydride

“…This ''thermodynamic sink'' is not available in the reaction of monocyclopentadienyl cobalt compounds with BH 3 AE thf since the formation of the 19-electron [Co(g-C 5 H 5 ) 2 ] is far less favourable. Fehlner reports that reaction of monocyclopentadienyl metal chlorides with BH 3 AE thf gives metallocene formation for manganese and iron and metal formation for nickel, whereas for cobalt and second or third row monocyclopentadienyl metal chlorides from Groups 5 to 9 a range of metallaboranes are formed [43,[45][46][47]. They postulate that hydride formation occurs from loss of borane from a metal borohydride which can lead to metal reduction or metallocene formation.…”