[{Fe(PEt₃)₃}₂(μ-H)₆B][BPh₄]:  A Complex Containing Octahedral Hypercoordinate Boron

Expanding metallaborane chemistry: an octahedral BH6moiety supported through M–H–B bridges

“…This remarkable coordination environment for boron appears to be a consequence of the elongated B-H bonds, which are supported by the stable and well-known fac-P 3 FeH 3 fragment on either side of the boron atom. During the course of this research, the similar complex [(Et 3 P) 3 Fe(BH 6 )Fe(PEt 3 ) 3 ] þ was reported by Berke et al 7 However, the ruthenium analogue of 2 appears as the more y CCDC reference number for 2*: 224893. See http://www.rsc.org/ suppdata/nj/b4/b401442c/ for crystallographic data in .cif or other electronic format.…”

“…Berke et al reported comparable spectroscopic data for [(Et 3 P) 3 Fe-(BH 6 )Fe(PEt 3 ) 3 ] þ , and interpreted them in a similar way. 7 The synthesis of 2 from 1 represents a novel departure in metallaborane chemistry, in that terminal M-H moieties are drawn into the expanded coordination sphere of the boron atom on coupling of the two metal centres. Synthetic strategies including hydride-borohydride precursors thus hold out the prospect of novel hydrogen-rich metallaborane complexes containing hypervalent or hypercoordinate boron centres.…”

High-spin and low-spin iron(ii) complexes with facially-coordinated borohydride ligands

“…5 Transition metal and lanthanide tetrahydridoborate complexes with varying degrees of stability and reactivity have been reported, 6 including recent reports of a nickel tetrahydridoborate complex 7 and a Mo-Fe cluster with terminal borohydride anions. 8 Although low-spin hexahydridoborate-bridged diiron(II) complexes were recently reported, 9 mononuclear iron tetrahydridoborate complexes are rare. 10, 11 Prior attempts to isolate the homoleptic borohydride Fe(BH 4 ) 2 were hindered by complex product mixtures due to the thermal instability of the product(s).…”

Dative N→P/Si Interactions — A Historical Approach [1]

“…[83]. Hillier et al [88]. As bond angles yield easily to steric constraints, the method is obviously inapplicable to molecules in which such forces play a significant role.…”