845870-37-3Relevant academic research and scientific papers
Lanthanide metallocene reactivity with dialkyl aluminum chlorides: Modeling reactions used to generate isoprene polymerization catalysts
Evans, William J.,Champagne, Timothy M.,Giarikos, Dimitrios G.,Ziller, Joseph W.
, p. 570 - 579 (2005)
The well-defined coordination environment of trivalent [(C 5Me5)2Ln]+ complexes has been used to examine the reaction chemistry of the lanthanide carboxylate and R 2AlCl (R = Me, Et, iBu) components used in the preparation of lanthanide-based diene polymerization catalysts. Each of the R 2AlCl reagents can replace a carboxylate ligand with chloride in reactions with [(C5Me5)2Sm(O2CC 6H5)]2, but instead of forming a simple chloride complex like [(C5Me5)2SmCl] 3, bimetallic lanthanide aluminum dichloro complexes (C 5Me5)2Sm-(μ-Cl)2AlR2 are generated by ligand redistribution. These bis(chloride)-bridged complexes are also readily formed from the divalent precursor (C5Me 5)2Sm(THF)2 and R2AlCl. However, the analogous reaction between (C5Me5)2Sm(THF) 2 and Et3Al gives (C5Me5) 2Sm(THF)-(μ-2-Et)AlEt3, which contains the first Ln(III)-(η2-Et) linkage, a coordination mode that differentiates Et from Me. To determine if mixed mono-chloride/alkyl-bridged (C5Me5)2Ln-(μ-Cl)(μ-R)AlR2 complexes can be isolated, (C5Me5)2Y(μ-Cl) YCl(C5Me5)2 was reacted with R3Al. These reactions form [(C5Me5)2Y(μ-Cl)(μ- R)AlR2]x complexes, but again there is a differentiation on the basis of R: the Me complex is a dimer and the others are monomers. (C5Me5)2Y(μ-Cl)2AlR2 complexes were similarly prepared for comparison with the mixed ligand species and for additional Me, Et, and iBu comparisons.
