Samarium, tris structure

Samarium, tris(triphenylphosphine oxide)bis-(diethyldithiophosphato)-structure, 1,78 Samarium complexes dipositive oxidation state hydrated ions, 3, 1109 Samarium(III) complexes salicylic acid crystal structure, 2, 481 Sampsonite, 3, 265... 

Samarium, tris(triphenylphosphine oxide)bis-(diethyldithiophosphato)-structure, 78... 

Lundin (1966) tried to include alloys of the lanthanum-lutetium system in his study of the formation of the samarium-type structure in intra rare earth alloys. The wide differences in the melting points (La 918°C Lu 1663°C) and densities (La 6.146 g/cm Lu 9.841 g/cm ) allowed the lutetium to settle to the bottom of molten lanthanum during the alloying process. Alloys were inverted and remelted several times to improve the homogeneity. Lundin reported (1) lanthanum-lutetium alloys formed a complex microstructure that had a different appearance than that of the samarium-type structure formed in the other alloy systems between a light and a heavy lanthanide or yttrium metal and (2) X-ray analysis failed to confirm the... 

This point is borne out by the structure of tris indenyl samarium (5d). An earlier report of the nmr spectrum was interpreted as evidence of covalent bonding in the tetrahydrofuran adduct of samarium triindenide 66). Indenyl anion. 

In a similar manner, treatment of anhydrous rare earth chlorides with three equivalents of lithium 1,3-di-ferf-butylacetamidinate (prepared in situ from di-fert-butylcarbodiimide, Bu -N=C=N-Bu , and methyllithium) afforded Ln[MeC (NBu )2]3 (Ln = Y, La, Ce, Nd, Eu, Er, Lu) in 57-72% isolated yields [6,7,26]. X-ray crystal structures of these complexes demonstrated monomeric formulations with distorted octahedral geometry around the lanthanide(III) ions (Eig. 3, Ln = La). The new complexes are thermally stable at >300°C, and sublime without decomposition between 180-220°C/0.05Torr. Other series of homoleptic lanthanide tris(amidinates) include the -cyclohexyl-substituted derivatives [RC(NCy)2]3Ln(THF)n (R = Me, Ln = Nd, Gd, Yb, n = 0 R = Ph, Ln = Nd, Y, Yb, n = 2). A sterically hindered homoleptic samarium(III) tris(amidinate), Sm[HC(NC6H3Pr 2-2,6)2]3, was obtained by oxidation of the corresponding Sm(II) precursor (cf.. Scheme 8) [6,7]. 

A recent exhaustive review [1] presents the known and well characterised lanthanide hydrides. Recently, a few additional original complexes have been synthesised. These include phospholyl [7] and indenyl derivatives [8], a bimetallic metallocenic structure (Scheme 1) [4], a samarium hydride supported by a calix-tetrapyrrolyl ring, with a triply bonded hydride ligand (Scheme 2) [9], metallocenes with chiral groups which has been used for the asymmetric hydrogenation [10], a tris(pyrazolyl)borate ytterbium(II) hydride [11], Cp amido-[12] and bis(amido)yttrium hydrides [13]. The latter was not isolated but obtained in situ from the methyl derivative (Scheme 2). 

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