Cluster lanthanide hydride clusters

Yet another lanthanide hydride cluster with a Cp ligand sterically hindered by noncoordinating substituent(s) is [Lu4(l, 3-C5H3Bu2)4H4] [AlH4(Et20)]2[AlH4]2 (Knjazhanski et al., 1991) the structure of which is shown in Figure 58. 

Amidopyridinate ligands also lead to the assembly and stabilization of lanthanide hydride clusters. The reaction of [ApR(CH2SiMe3)2(THF)] (R = Y, Lu Ap = (2,6-diisopropylphenyl)[6-(2,4,6-triisopropylphenyl) pyridin-2-yl]aminate) with either PhSiHs or H2 afforded trinuclear alkyl-hydrido clusters [(ApR)3(/i2-H)3(/i3-H)2(CH2SiMe3)(THF)2] (Lyubov et al., 2008). 

FIGURE 61 Synthesis (top) and crystal structure (bottom left) of trinuclear lanthanide hydride clusters obtained with a monoanionic cyclen-type ancillary ligand. The coordination environment of one particular metal atom is shown on the bottom right (redrawn after Ohashi et al., 2008). 

FIGURE 62 Synthesis of trinuclear lanthanide hydride clusters with an amidopyridinate ligand (top). The crystal structure of the Y(lll) cluster is shown (bottom) (redrawn after Lyubov et al., 2008). 

Addamo, M., Bombieti, G, Foresti, E., Grillone, M.D., and Volpe, M. (2004) Assembling process of charged nonanuclear cationic lanthanide(lll) clusters assisted by dichromium decacarbonyl hydride. Inorganic Chemistry, 43, 1603—1605. 

Volpe, M., Bombieri, G, and Marchini, N. (2006) Synthesis and X-ray crystal structure of cationic polynuclear hydroxide acetylacetonate lanthanide(lll) clusters with homodinuclear or heterodinuclear decacarbonyl hydrides [HMo2(CO)io] and [HCrW(CO)io] . Journal of Alloys and Compounds, 608-612, 1066-1051. 

Reaction of tetranuclear lanthanide octahydrides with styrene provides lanthanide benzylic allyl heptahydride complexes through the insertion of a styrene molecule into one Ln-H bond. The lanthanide benzylic allyl complexes can be considered as the intermediates of styrene hydrogenation. Indeed, both the lanthanide octahydrides and the lanthanide benzylic allyl complexes can catalyze styrene hydrogenation efficiently in the presence of H2 [89]. Lanthanide hydrides react with 1,3-cyclohexadiene to form lanthanide allylic complexes via 1,4-addition [90]. However, these lanthanide hydride clusters can not catalyze the polymerization of styrene and 1,4-cyclohexadiene. 

Additional areas of lanthanide halide chemistry that have been reviewed include the synthesis, phase studies, and structures of complex lanthanide halides - compounds formed between one or more group 1 cation and lanthanide element halides (Meyer 1982). Halides in combination with lanthanide elements in the II, III, and IV oxidation states were considered with the chemistry of the heavier halides being emphasized. More recently the reduced ternary lanthanide halides (Meyer 1983) and the reduced halides of the lanthanide elements were reviewed (Meyer 1988). The latter review considered lanthanides in which the formal oxidation state of the cation was 2 and included hydride halides, oxide halides, mixed-valence ternary halides, and reduced halide clusters. Corbett et al. (1987) discussed the structures and some bonding aspects of highly reduced lanthanide halides and compounds stabilized by a second-period element bound within each cluster, e.g., SC7CIJ2B, SC5CI5B, YjCljC. 

Cheng J, Sahu K, Kiel GY, Ferguson M, McDonald R, Takats J. Scorpionate-supported dialkyl and dihydride lanthanide complexes Ugand- and solvent-dependent cluster hydride formation. Angew Chem Int Ed Engl. 2008 47 4910-4913. 

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