Chemistry of oxo-alkoxides of metals

Mehrotra, R. C.; Singh, Anirudh

doi:10.1039/cs9962500001

Cited by 94 publications

(65 citation statements)

References 32 publications

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“…[13] It is apparent that solvent and ligand deoxygenation to oxo species is facilitated by impurities such as water Scheme 3. [14,15] Controlled hydrolysis of TiÀCl and TiÀOR bonds is a convenient route to titanoxanes involving either oxo-bridged linkages (Ti-O-Ti) or terminal-bonded titanyl (TiO) moieties. [13] Electrochemical investigations: The electrochemical behaviour of complexes 1, 2 and 4 ± 7 (Table 1) cyclic voltammetry (CV) and controlled potential electrolysis (CPE) in aprotic medium, [NBu 4 ][BF 4 ] 0.2 mol dm À3 /CH 2 Cl 2 (or THF), at a Pt-disc or -gauze electrode, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Syntheses, Structure, and Reactivity of Chiral Titanium Compounds: Procatalysts for Olefin Polymerization

et al. 2001

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Titanium complexes with chelating alkoxo ligands have been synthesised with the aim to investigate titanium active centres in catalytic ethylene polymerisation. The titanium complexes cis-[TiCl2(eta2-maltolato)2] (1, 89%), and cis-[TiCl2(eta2-guaiacolato)2] (2, 80%) were prepared by direct reaction of TiCl4 with maltol and guaiacol in toluene. The addition of maltol to [Ti(OiPr)4] in THF results in the formation of species [Ti(OiPr)2(maltolato)2] (3, 82%). The titanium compound cis-[Ti(OEt)2(eta2-maltolato)2] (4, 74%) was obtained by the transesterification reaction of species 3 with CH3CO2Et. When compound 4 is dissolved in THF a dinuclear species [Ti2(mu-OEt)2(OEt)4-(eta2-maltolato)2] (5, 45%) is formed. Reaction of [Ti(OiPr)4] with crude guaiacol in THF yields a solid, which after recrystallisation from acetonitrile gives [Ti4(mu-O)4(eta2-guaiacolato)] x 4CH3CN (6, 55%). In contrast, reaction of TiCl4 with crude guaiacol in tetrahydrofuran affords [Ti2(mu-O)Cl2(eta2-guaiacolato)4] (7, 82%). Crystallographic and electrochemical analyses of these complexes demonstrate that maltolato and guaiacolato ligands can be used as a valuable alternative for the cyclopentadienyl ring. These complexes have been shown to be active catalysts upon combination with the appropriate activator.

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Section: Resultsmentioning

confidence: 99%

“…The displacement ellipsoids are drawn at the 50 % probability level. Selected bond lengths [pm] and angles [deg]: TiÀO(1) 179.64(14)…”

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Syntheses, Structure, and Reactivity of Chiral Titanium Compounds: Procatalysts for Olefin Polymerization

et al. 2001

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“…2 has been characterized by IR spectroscopy, and the solid state structure was established by single crystal X-ray diffraction In contrast to the formation of 1 we do not assume that the encapsulated oxygen atom of 2 is derived from a THF cleavage [6]. Even though the tendency to incorporate oxygen from`pure' organic solvents to form oxo-centered clusters is well documented for lanthanide alkoxides [10], we cannot exclude that the encapsulated oxygen atom is derived either from traces of moisture in the solvents [11] or from high-vacuum grease [12]. Z We are grateful to the Deutsche Forschungsgemeinschaft (Habilitation fellowship) and to the Fonds der Chemischen Industrie for financial support.…”

Section: -O)li 3 ] (2) Was Performed By Transmetallation Of LI 3 [N Hmentioning

confidence: 99%

Synthesis of a Triamidoamine Nd2Cl2(μ5-O)Li3 Cluster

Wetzel

Roesky

1999

Z. anorg. allg. Chem.

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“…Oxo-alkoxides are more stable than the corresponding alkoxides and, of course, are less reactive toward hydrolysis and condensation. 7 Alkoxide precursors are usually dissolved in a solvent so that coordination expansion can also occur via solvation. Solvate formation is often observed when alkoxides are dissolved in their parent alcohol.…”

Section: Molecular Structure Of Metal Alkoxidesmentioning

confidence: 99%

Sol–Gel Synthesis of Solids

Coradin

2004

Encyclopedia of Inorganic and Bioinorganic Chemistry

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The synthesis of glasses and ceramics via the sol–gel route is based on the inorganic polymerization of molecular precursors such as metal alkoxides. Precursor structure and reactivity can be chemically controlled via complexation or acid–base catalysis. Sol–gel chemistry allows the powderless processing of glasses and ceramics, at much lower temperatures than that at usual solid‐state reactions. It provides a convenient and flexible access to nanoparticles, films, and fibers. Moreover, precursors are mixed at the molecular level and multicomponent materials can be formed. Thus, hybrid organic–inorganic materials have been made via the sol–gel route. The organic component can be used as a network modifier during the sol–gel synthesis and then withdrawn, allowing the formation of structured porous materials. It can also remain entrapped in the mineral matrix via weak interactions. Alternatively, organoalkoxysilanes allow covalent binding of organic moieties to silica networks. Such composites fill the gap between polymers and glasses, opening new possibilities for the design of functional materials in the fast developing areas of energy, biotechnology, and medicine.

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Chemistry of oxo-alkoxides of metals

Cited by 94 publications

References 32 publications

Syntheses, Structure, and Reactivity of Chiral Titanium Compounds: Procatalysts for Olefin Polymerization

Syntheses, Structure, and Reactivity of Chiral Titanium Compounds: Procatalysts for Olefin Polymerization

Synthesis of a Triamidoamine Nd2Cl2(μ5-O)Li3 Cluster

Sol–Gel Synthesis of Solids

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