The reaction of lanthanide and yttrium hydrocarbyls {Cp*2Ln(μ-Me)}2 (Cp* = tBuC5H4 (Cp‘), Ln = Y (1), Tb (2), Yb (3), Lu (4); Cp* = Me3SiC5H4 (Cp‘‘), Ln = Lu (5)), one of which, 2, has been characterized by X-ray crystal analysis, with various organosilicon, -germanium, and -tin hydrides (as well as some organoaluminum and -gallium hydrides) in hydrocarbon solution was found to yield the corresponding unsolvated dimeric lanthanide and yttrium hydrides {Cp*2Ln(μ-H)}2 rather than compounds with lanthanide−element (Si, Ge, Sn) bonding. Thus, the reaction involves hydride transfer to Ln rather than the silyl transfer studied earlier for pentamethylcyclopentadienyllanthanide hydrocarbyls. Dimeric compounds Cp*2Ln(μ-H)(μ-Me)LnCp*2 with different bridging ligands were isolated; they are intermediates in this reaction. Dimeric lanthanide and yttrium hydrides catalyze the H/D exchange in silanes. This catalytic reaction is most correctly described by a mechanism involving nucleophilic substitution at the silicon atom. Yttrium and lutetium hydrocarbyls 1 and 4 react with various alkoxysilanes to produce the dimeric alkoxides {Cp‘2Ln(μ-OR)}2 or the hydrocarbyl alkoxides Cp‘2Ln(μ-Me)(μ-OR)LnCp‘2 (R = Me, Et), depending on the reaction conditions. The reaction of 4 with (MeO)4Si provided Cp‘2Lu(μ-Me)(μ-OMe)LuCp‘2, which has been characterized by X-ray crystal analysis. This compound contains one methyl bridge (Lu−C 2.57(2) and 2.58(2) Å) and nonsymmetrically bonded μ-OMe ligand (Lu−O 2.20(2) and 2.12(2) Å). The reaction of 1 and 4 with Me3SiCl leads to the corresponding dimeric chlorides {Cp‘2Ln(μ-Cl)}2 only. Thus, the reaction of lanthanide and yttrium hydrocarbyls with various heterosubstituted organosilanes R3SiX, where X = H, OR, or Cl, is a selective and convenient synthetic method in the chemistry of the group 3 elements. Complexes with Ln(μ-H)(μ-Me)Ln and Ln(μ-H)(μ-Cl)Ln bridging were prepared in high yield by the exchange reactions between the corresponding dimeric compounds {Cp*2Ln(μ-X)}2 (X = H, Me, Cl) in a hydrocarbon solution. The capacities of various bridging fragments to undergo reversible cleavage (dissociation) in the hydrocarbon solution increase in the sequence Ln−O(Me)−Ln ≪ Ln−Cl−Ln < Ln−H−Ln < Ln−Me−Ln.

The review summarises data on transition metal com-The review summarises data on transition metal complexes with the so-called non-innocent ligands. The specific plexes with the so-called non-innocent ligands. The specific feature of these complexes is that the oxidation state of the central feature of these complexes is that the oxidation state of the central metal atom and the electronic structure of the ligands are metal atom and the electronic structure of the ligands are impossible to determine impossible to determine a priori a priori and unambiguously. The results and unambiguously. The results of experimental studies (spectroscopic, electrochemical, X-ray of experimental studies (spectroscopic, electrochemical, X-ray diffraction) of complexes with various non-innocent ligands are diffraction) of complexes with various non-innocent ligands are analysed. Particular attention is given to their structures and analysed. Particular attention is given to their structures and redox properties. The bibliography includes 208 references redox properties. The bibliography includes 208 references. .

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