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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

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