The first metallasilsesquioxane bearing pyrazolylpyridine ligands, the Cu-based complex 1, adopts a cage-like structure with two zigzag-type copper tetramers sandwiched by two cyclic Si silsesquioxane ligands. The four 3-phenyl-5-(2-pyridyl)pyrazolate ligands in 1 exhibit dual (chelating and bridging) modes of ligation. Compound 1 is very active in the oxidation of alkanes and alcohols.
View Article and Find Full Text PDFWe report a high nuclear (Cu) complex synthesized via the self-assembly of copper-methylsilsesquioxane induced by the complexation with 1,2-bis(diphenylphosphino)ethane (dppe). The structure includes two cationic Cu(dppe) moieties and an anionic silsesquioxane cage of an unprecedented Cu structural type. The Cu cage fragment exhibits a unique () combination of Si-cyclic/Si-acyclic silsesquioxane ligands and () encapsulation of two different chloride and carbonate species.
View Article and Find Full Text PDFAn extended (, 19 distinct species) family of cage-like Cu-phenylsilsesquioxanes allowed us to accentuate the general regularities behind their structural organization. Influencing factors, namely the (i) size of external alkali metal ions (from Li to Cs) and (ii) nature of bridging linkers (including the smallest possible ones, like a water molecule) on the self-assembly/supramolecular assembly of such Cu-building blocks have been thoroughly explored. A CuK-based complex has been evaluated as a precatalyst in the oxidation of alkanes (cyclohexane, -heptane, methylcyclohexane) and alcohols.
View Article and Find Full Text PDFConvenient self-assembly synthesis of copper(II) complexes via double (phenylsilsesquioxane and acetate) ligation allows to isolate a family of impressive sandwich-like cage compounds. An intriguing feature of these complexes is the difference in the structure of a pair of silsesquioxane ligands despite identical (Cu) nuclearity and number (four) of acetate fragments. Formation of particular combination of silsesquioxane ligands (cyclic/cyclic vs condensed/condensed vs cyclic/condensed) was found to be dependent on the synthesis/crystallization media.
View Article and Find Full Text PDFUnprecedented iron-based silsesquioxane/acetylacetonate complexes were synthesized. The intriguing cage-like structure of compounds is alkaline metal-dependent: the FeLi complex includes condensed Si-silsesquioxane and four acetylacetonate ligands; the FeNa complex exhibits two cyclic Si-silsesquioxane and eight acetylacetonate ligands, while the FeK complex features two cyclic Si-silsesquioxane and six acetylacetonate ligands. The latter case is the very first observation of small trimeric silsesquioxane ligands in the composition of cage-like metallasilsesquioxanes.
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