Nucleophilic substitution on a Ru-coordinated Cp ring by a carborane anion

Abstract

The Cp ring in [RuCl(Cp)(PPh3)2] undergoes an apparent nucleophilic attack by the carbanion carb- (Hcarb = 2-Me-1,2-dicarba-closo-dodecaborane), to give an H-/carb- exchange process, which is favoured by coordination of the hydride to the ruthenium centre.

Reaction of Cyclopentadienyl Ruthenium Complexes with a Carborane Anion: Effect of the Spectator Ligands on the Substitution Site

“…The first investigated complex was [RuCl(Cp)(PPh 3 ) 2 ], and we justified the rather unexpected nucleophilic attack by the carboranyl anion at the Cp ring on the basis of the steric hindrance of the bulky triphenylphosphine ligands around the metal center . The importance of steric factors in determining the site of nucleophilic attack has been confirmed by the behavior exhibited by the bis-phosphine complexes [RuCl(Cp)L 1 L 2 ] (L 1 , L 2 = PPh 3 , PMe 2 Ph, PMePh 2 ; L 1 L 2 = dppe).…”

“…The FTIR spectra of the hydrido compounds show, in particular, two bands: a narrow one with low intensity at 1970 cm -1 (stretching Ru−H) and a rather broad one centered at 2570 cm -1 (stretching B−H). The whole of these data, together with 2-D NMR spectra and NOE correlations, allows us to propose for 5 and 6 the same structure determined for 1 : a three-legged piano-stool structure with the hydride located under the carboranyl substituent and the neutral ligands positioned opposite to it …”

“…In this context, we were surprised by the preliminary results obtained in the reaction of [RuCl(Cp)(PPh 3 ) 2 ] with an ethereal solution of Licarb (Hcarb ) 2-Me-1,2-dicarba-closo-dodecaborane). 5 In fact, instead of a simple Cl -/carbexchange product, we isolated a hydrido Ru(II) complex, [RuH(C 5 H 4 -carb)(PPh 3 ) 2 ] (1), resulting from a formal nucleophilic attack of carbon the cyclopentadienyl group. To our knowledge, this was the first example of a nucleophilic substitution reaction on a Cp ring coordinated to a fairly electron-rich metal center such as ruthenium(II).…”

Dicarba-closo-dodecarborane-containing half-sandwich complexes of ruthenium, osmium, rhodium and iridium: biological relevance and synthetic strategies

“…91 Scheme 7 Synthesis of complex 43. 93 complex of ruthenium in which the cyclopentadienyl ring is functionalized with a dicarba-closo-dodecarborane moiety. 96 In 2006, the same authors published an extension of this work in-which a series of cyclopentadienyl-carboranyl halfsandwich complexes of ruthenium was synthesised following the same strategy.…”

Half-pseudoferrocene cations from nucleophilic addition of o-carboranyl anions to the [(η6-mesitylene)2Fe]2+ dication

“…These types of reactions have been reported mostly for carbanions and other strong nucleophiles (for example, H − ) and are known to be strongly affected and restricted by the nature of the nucleophile, arene, and solvent used. 3 Although nucleophilic addition reactions of the [2-Me-1,2-C 2 B 10 H 10 ] − anion to the cyclopentadiene ring in [RuCl(Cp)(PPh 3 ) 2 ] and to the arene ring in [(η 6 -arene)Cr-(CO) 3 ] have been reported 4,5 no addition reactions of σ-bonding carborane anions to iron-complexed arenes have surprisingly been examined. Therefore we believe that this paper will represent the first successful attempt in the area of iron-arene chemistry.…”