Cyclopentadienyl-silsesquioxane titanium compounds as suitable candidates for immobilization on silica-based supports

Mateos, María Espada; Vinueza, Joan; Mosquera, Marta E.G.; Tabernero, Vanessa; Cuenca, Tomás; Jiménez, Gerardo

doi:10.1016/j.ica.2019.119275

Cited by 7 publications

(5 citation statements)

References 64 publications

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“…Titansiloxanes are of considerable scientific and practical interest. They have been widely used as Ziegler-Natta catalysts [17][18][19][20], oxidation and polymerization catalysts [21][22][23], and for epoxidation [24,25]. In addition, they are precursors of materials for medicine and microbiology [26,27].…”

Section: Introductionmentioning

confidence: 99%

Interaction of Polyphenylsilsesquioxane with Various β-Diketonate Complexes of Titanium by Mechanochemical Activation

Libanov

Капустина

Шапкин

et al. 2023

Powders

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In the present work, we studied the interaction of polyphenylsilsesquioxane with various β-diketonate complexes of titanium by mechanochemical activation. Polyphenylsilsesquioxane, bis-(2,4-pentanedionate) titanium dichloride, bis-(1-phenyl-1,3-butanedionate) titanium dichloride, and bis-(1,3-diphenyl-1,3-propanedionate) titanium dichloride were used as starting reagents. Various chemical and physicochemical methods of analysis were used to study the synthesis products. The composition of the obtained compounds has been determined. It is shown that under conditions of mechanochemical activation, high-molecular-weight products with a Si/Ti ratio different from the specified ones are formed. In addition, under the action of mechanical stresses, the initial titanium complexes (except for acetylacetonate complex) polymerize with the formation of coordination of high-molecular-weight compounds, which are destroyed by the addition of ethyl alcohol. It has been established that with an increase in the volume of the organic ligand, titanium atoms enter the polymer siloxane chain to a lesser extent. This work is aimed at finding efficient and environmentally friendly methods for the synthesis and modification of organometallic macromolecular compounds.

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Section: Introductionmentioning

confidence: 99%

Interaction of Polyphenylsilsesquioxane with Various β-Diketonate Complexes of Titanium by Mechanochemical Activation

Libanov

Капустина

Шапкин

et al. 2023

Powders

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“…General synthetic methods for cagelike metallasilsesquioxanes involve (i) “synthone approach” with individual, , cyclic (Si 4 ), or polyhedral Si 6 , and Si 7 − silanols as starting reagents. The alternative approach implies self-assembly with RSi(O)O-siloxanolate units. , In addition, several examples of structural transformations of already synthesized metallasilsesquioxanes were reported, giving new types of cage cores via oxidative rearrangement, transmetalation, , or use of additional organic ligands. − Among all of these synthetic methods, several examples point out an important role of solvating systems (reaction media) in the structural parameters of the resulting cagelike products (Table , Figure S1, SI).…”

Section: Introductionmentioning

confidence: 99%

Acetone Factor in the Design of Cu₄-, Cu₆-, and Cu₉-Based Cage Coppersilsesquioxanes: Synthesis, Structural Features, and Catalytic Functionalization of Alkanes

et al. 2022

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The present study describes a new feature in the self-assembly of cagelike copperphenylsilsesquioxanes: the strong influence of acetone solvates on cage structure formation. By this simple approach, a series of novel tetra-, hexa-, or nonacoppersilsesquioxanes were isolated and characterized. In addition, several new complexes of Cu4 or Cu6 nuclearity bearing additional nitrogen-based ligands (ethylenediamine, 2,2′-bipyridine, phenanthroline, bathophenanthroline, or neocuproine) were produced. Single-crystal X-ray diffraction studies established molecular architectures of all of the synthesized products. Several coppersilsesquioxanes represent a novel feature of cagelike metallasilsesquioxane (CLMS) in terms of molecular topology. A Cu4–silsesquioxane complex with ethylenediamine (En) ligands was isolated via the unprecedented self-assembly of a partly condensed framework of silsesquioxane ligands, followed by the formation of a sandwich-like cage. Two prismatic Cu6 complexes represent the different conformersregular and elliptical hexagonal prisms, “cylinders”, determined by the different orientations of the coordinated acetone ligands (“shape-switch effect”). A heterometallic Cu4Na4-sandwich-like derivative represents the first example of a metallasilsesquioxane complex with diacetone alcohol ligands formed in situ due to acetone condensation reaction. As a selected example, the compound [(Ph6Si6O11)2Cu4En2]·(acetone)2 was explored in homogeneous oxidation catalysis. It catalyzes the oxidation of alkanes to alkyl hydroperoxides with hydrogen peroxide and the oxidation of alcohols to ketones with tert-butyl hydroperoxide. Radical species take part in the oxidation of alkanes. Besides, [(Ph6Si6O11)2Cu4En2]·(acetone)2 catalyzes the mild oxidative functionalization of gaseous alkanes (ethane, propane, n-butane, and i-butane). Two different model reactions were investigated: (1) the oxidation of gaseous alkanes with hydrogen peroxide to give a mixture of oxygenates (alcohols, ketones, or aldehydes) and (2) the carboxylation of C n gaseous alkanes with carbon monoxide, water, and potassium peroxodisulfate to give C n+1 carboxylic acids (main products), along with the corresponding C n oxygenates. For these reactions, the effects of acid promoter, reaction time, and substrate scope were explored. As expected for free-radical-type reactions, the alkane reactivity follows the trend C2H6 < C3H8 < n-C4H10 < i-C4H10. The highest total product yields were observed in the carboxylation of i-butane (up to 61% based on i-C4H10). The product yields and catalyst turnover numbers (TONs) are remarkable, given an inertness of gaseous alkanes and very mild reaction conditions applied (low pressures, 50–60 °C temperatures).

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“…Titansiloxanes are of considerable scienti c and practical interest. They are widely used as Ziegler-Natta catalysts [17], catalysts for oxidation and polymerization [18][19][20], and epoxidation [21,22]. In addition, they are precursors of materials for medicine and microbiology.…”

Section: Introductionmentioning

confidence: 99%

Interaction of Polyphenylsilsesquioxane With Various β-diketonate Complexes of Titanium By Mechanochemical Activation

Libanov

Капустина²,

Шапкин³

et al. 2022

Preprint

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In the present work, we studied the interaction of polyphenylsilsesquioxane with various β-diketonate complexes of titanium by mechanochemical activation. Polyphenylsilsesquioxane, bis-(2,4-pentanedionate) titanium dichloride, bis-(1-phenyl-1,3-butanedionate) titanium dichloride and bis-(1,3-diphenyl-1,3-propanedionate) titanium dichloride were used as starting reagents. Synthesis products were studied by various chemical and physicochemical methods of analysis. The composition of the obtained compounds has been determined. It is shown that under conditions of mechanochemical activation, high molecular weight products with a Si/Ti ratio different from the specified ones are formed. In addition, under the action of mechanical stresses, the initial titanium complexes (with the exception of acetylacetonate) polymerize with the formation of coordination high-molecular compounds, which are destroyed by the addition of ethyl alcohol. The work is fundamental and contributes to the understanding of the mechanisms of mechanochemical synthesis. The work is aimed at finding effective and environmentally friendly methods for the synthesis and modification of elementorganic high-molecular compounds.

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Cyclopentadienyl-silsesquioxane titanium compounds as suitable candidates for immobilization on silica-based supports

Cited by 7 publications

References 64 publications

Interaction of Polyphenylsilsesquioxane with Various β-Diketonate Complexes of Titanium by Mechanochemical Activation

Interaction of Polyphenylsilsesquioxane with Various β-Diketonate Complexes of Titanium by Mechanochemical Activation

Acetone Factor in the Design of Cu₄-, Cu₆-, and Cu₉-Based Cage Coppersilsesquioxanes: Synthesis, Structural Features, and Catalytic Functionalization of Alkanes

Interaction of Polyphenylsilsesquioxane With Various β-diketonate Complexes of Titanium By Mechanochemical Activation

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Cyclopentadienyl-silsesquioxane titanium compounds as suitable candidates for immobilization on silica-based supports

Cited by 7 publications

References 64 publications

Interaction of Polyphenylsilsesquioxane with Various β-Diketonate Complexes of Titanium by Mechanochemical Activation

Interaction of Polyphenylsilsesquioxane with Various β-Diketonate Complexes of Titanium by Mechanochemical Activation

Acetone Factor in the Design of Cu4-, Cu6-, and Cu9-Based Cage Coppersilsesquioxanes: Synthesis, Structural Features, and Catalytic Functionalization of Alkanes

Interaction of Polyphenylsilsesquioxane With Various β-diketonate Complexes of Titanium By Mechanochemical Activation

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Acetone Factor in the Design of Cu₄-, Cu₆-, and Cu₉-Based Cage Coppersilsesquioxanes: Synthesis, Structural Features, and Catalytic Functionalization of Alkanes