Synthesis and structural study of new metallasilsesquioxanes of potassium and uranium.

The first metallasilsesquioxanes comprising potassium and uranium have been synthesized and structurally characterized by single-crystal X-ray diffraction. (CySiO)K(DME) (2; Cy = cyclohexyl) is a centrosymmetric dimer, in which the two silsesquioxide ligands are interconnected by μ- and μ-bridging siloxide moieties. (CySiO)U (3) represents the first metallasilsesquioxane complex of an actinide element, featuring a U atom that is coordinated by two tridentate silsesquioxide ligands in a distorted octahedral fashion.

Unusual inorganic ring systems of scandium and yttrium containing group 13 Metals: coordination of monomeric Me(2)InOMe to yttrium.

Novel transformations of lanthanide(III) disiloxanediolates with group 13 metal trialkyls are reported. Treatment of the scandium metallacrown complex [{(Ph2SiO)2O}2{Li(DME)}2]ScCl.THF (1) with AlMe3 resulted in an Li-Al exchange reaction and the formation of the heterotrimetallic inorganic ring system [{(Ph2SiO)2O}2{Li(THF)2}AlMe2]ScCl.

Structural varieties in heterobimetallic lanthanide disiloxanediolates: "inorganic metallocenes" versus in-plane metallacrowns.

The previously proposed concept of "inorganic metallocenes" of group 3 and rare-earth elements has been tested by preparing a series of novel disiloxanediolates with metals displaying different ionic radii. For the smaller scandium and yttrium, approximately planar arrangements of the disiloxanediolate frameworks with solvent and chloride ligands in trans positions were found. Thus, the compounds [{(Ph2SiO)2O}2{Li(DME)}2]ScCl(THF/DME) (2; DME=1,2-dimethoxyethane and THF=tetrahydrofuran) and [{(Ph2SiO)2O}2{Li(THF)2}2]YCl(THF) (3) can be described as heterobimetallic inorganic ring systems or metallacrown complexes with "in-plane" coordination of the metal.

Unprecedented examples of heterobimetallic cerium(IV) disiloxanediolates.

The first disiloxanediolate complexes of cerium(IV) are reported. Starting from the readily available precursor ((t)BuO)(3)Ce(IV)(NO(3))(THF)(2) (1), we prepared the novel heterobimetallic compounds [{(Ph(2)SiO)(2)O}{K(THF)(2)}](2)Ce(O(t)Bu)(2) (2) and [{(Ph(2)SiO)(2)O}(2){(DME)-KO(t)Bu}{(Ph(2)SiO(2))K}Ce](2) (3) and structurally characterized them by X-ray diffraction.