Samarium-mediated redistribution of silanes and formation of trinuclear samarium–silicon clusters

Abstract

The samarium complex Cp*2SmCH(SiMe& (Cp* = C5Me5), unlike the related alkyls Cp*zLnCH(SiMe& (Ln = Y, Nd), mediates the redistribution of hydrosilanes while being converted to trisamarium clusters, including Cp*6Sm3(~-SiH3)(~3-rl,~l,~~-SiH2-SiH2).Lanthanide-silicon chemistry is an emerging area with considerable potential, as indicated by recent reports which describe lanthanide-catalysed silane dehydroc~uplings~ and hydrosilylations.2 The development of this area has undoubtedly been slowed by the scarcity of lanthanide-silicon bonded compounds available for reactivity ~t u d i e s . ~We have recently reported a o-bond metathesis route to isolable lanthanide silyl derivatives c~"~LnSiH(SiMe3)~ (Ln = Y, Nd, Sm), which occurs by an autocatalytic reaction of alkyl complexes Cp*2LnCH(SiMe& with H2Si(SiMe3)2.4 In investigating the reactivity of lanthanide alkyls toward other silanes, we have also observed silane dehydroco~pling~a-c and silyl-alkyl coupling.4a.b Here, we report a new type of transformation resulting from interaction of a silane with a lanthanide alkyl complex, which leads to redistribution at silicon and formation of novel samarium-silicon clusters.Reaction of Cp*2SmCH(SiMe3)25 1 with PhSiH3 (1 equiv.) in [2H6]benzene occurs rapidly after a variable induction time (5-20 min)? to produce a deep red solution. By lH NMR spectroscopy, this reaction gives a quantitative yield of CH2(SiMe3)2, along with H2 (26%), PhSiH2-SiH2Ph (1 l%), Ph2SiH2 (46%), and Ph3SiH (trace). Quantitative transfer of deuterium label from PhSiD3 to the alkyl group [to produce CHD (SiMe&] implies that the first step in the reaction is formation of c ~* ~S r n S i H ~P h , but this species has not been identified as an intermediate. Similar distributions of products are observed for reactions of PhSiH3 with 1, [ C P * ~S ~H ] ~, ~. ~ Cp*2SmSiH(SiMe3)2,4 and C P * ~S ~. ~ Complex 1 reacts slowly with Ph2SiH2 (1 equiv., [2H6]benzene, 22 "C) via redistribution

Non-traditional ligands in f-block chemistry

“…The competitive nature of s-bond reactions involving silanes and lanthanide hydrocarbyls, described above in the synthesis of 26, was exemplified by a collection of samarium(III ) clusters reported by Tilley, which contain unsupported Sm-Si bonds (scheme 10) (Radu et al 1996a). The reaction between phenylsilane and [Sm(h 5 -C 5 Me 5 ) 2 {CH(SiMe 3 ) 2 }] gave a complicated mixture of products from multiple s-bond reactions.…”

“Self-Assembly” in Organolanthanide Chemistry: Formation of Rings and Clusters

“…[14] The presence of small and hard ligands like H À and F À seems to encourage ring formation. [14] The presence of small and hard ligands like H À and F À seems to encourage ring formation.…”

(Aminocarbene)(Divinyltetramethyldisiloxane)Iron(0) Compounds: A Class of Low‐Coordinate Iron(0) Reagents

“…1 H and 29 Si NMR spectra corroborated these structure features, and agreed closely with the spectra of Caulton's cobalt(V) complexes. [6,19] The occurrence of the SiHPh(IEt 2 Me 2 ) ligand in 4 implies the involvement of hydrosilane redistribution in the reaction of 1 with Ph 2 SiH 2 , [21] probably facilitated by (IEt 2 Me 2 ) 2 Fe. The conversion of 1 into 4 has demonstrated the capability of the aminocarbene-stabilized iron(0) alkene compound to deliver its (aminocarbene)iron(0) fragment during the reaction course.…”