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Applications of Lanthanide Alkoxides

Lanthanide alkoxide complexes are of fundamental interest because of the associated synthetic challenges and the great variety of their structures. They are also an important class of materials, either as catalysts to promote useful but otherwise difficult chemical transformations or as molecular precursors for the realization of high-quality metal oxide-based advanced materials. Selected examples illustrating these applications are discussed below. [Pg.246]

Lanthanide alkoxide complexes have been shown to promote a number of useful chemical reactions, whereby the complex is used catalytically or applied in stoichiometric amount. One such reactions is the Meerwein-Ponndorf-Verley reduction (MPV) or the Oppenauer oxidation, depending on which component is the desired product (Equation 6.5). If the alcohol is the desired product, the reaction is viewed as Meerwein-Ponndorf-Verley Reduction [43]. [Pg.246]

Shibasaki and Groger developed lanthanide/alkali binapthoxide-based Lewis acid-Brpnsted base bifunctional catalysts [44]. One such example, the (R,R)-Ln-M-linked BINOL complex. [Pg.246]

Creating metal oxide based advanced materials using lanthanide alkoxide complexes as molecular precursors is another area where the lanthanide alkoxide chemistry has found significant applications [5, 7-10]. A technique heavily used in the semiconductor industry for the growth of metal oxides materials is the process of metal-organic vapor chemical vapor deposition [Pg.247]

Lanthanide aluminates (LnAlOJ are of interest as buffer layers in controlling the overgrowth of various perovskite films and as alternative gate dielectrics to Si02. Using the singlesource heterometallic lanthanide aluminum isopropoxide precursors [LnAl(OPr )6(HOPr )]2 [Pg.248]


Asymmetric ate complexes of type Na3Ln((S)-BINOL)3 6THF H20 (Ln = Pr, Nd, Eu) could be crystallized from THF and exist only in the /1-form [158], Their stability against moisture had an enormous impact on application of lanthanide alkoxides in organic synthesis (Sect. 6.2.1). [Pg.188]

The discussion below starts with the general synthesis of lanthanide alkoxides, followed by a summary of the OR (R = aliphatic or aryl) coordination modes. Selected examples of complexes will then be presented in order to illustrate the coordination chemistry unique to each class of these ligands (aliphatic alkoxido, aryloxido, and macrocyclic polyaryloxido). Toward the end, catalytic and materials applications of lanthanide alkoxide complexes will be discussed. [Pg.231]

Meerwein-Ponndorf-Verley-Oppenauer catalysts typically are aluminum alkox-ides or lanthanide alkoxides (see above). The application of catalysts based on metals such as ytterbium (see Table 20.7, entries 6 and 20) and zirconium [85, 86] has been reported. [Pg.601]

It is necessary to mention in particular the application of carboxylates of lanthanides instead of halides in the reactions with Li, Na, and K, alkoxides for the preparation of M(OR)3 -derivatives of almost all the lanthanides patented by Ozaki. The methoxides and n-buthoxides were thus obtained by interaction of formates with NaOR, the ethoxides by that of propionates with LiOEt, n-and isopropoxides by reaction of acetates or bensoates with LiOPr, t-buthox-ides by that of oxalates with KOBu [1246]. In addition to carboxylates for the interaction with NaOR using the easily accessible anhydrous Ln(OCOCCl3)3 [1494, 1159] was proposed. The adducts of Ln(N03)3 with glycols or polyethers were used for the preparation ofphenoxides [73]. [Pg.258]

Transesterification [236] and the ester exchange reaction [237] were reported to be efficiently catalyzed (Eqs. 30 and 31). Either of the exchange reactions are sensitive to steric constraints of the substrates and to metal ion size. For example, transesterification is most applicable to primary alcohols. Increased catalytic activity in the presence of larger lanthanide centers is explained by enhanced coordinative unsaturation and increased basicity of the alkoxide complexes. Strong basicity of the lanthanide isopropoxides is considered to catalyze effectively the transhydrocyanation from acetone cyanohydrin to sev-... [Pg.211]

It is a commonplace to say that there has been explosive growth in the use of lanthanides in organic chemistry. For many years, the use of cerium(iv) compounds as oxidants was widespread, but more recently a whole range of other compounds have made their appearance. Thus samarium(ii) compounds are now routinely used as one-electron reducing agents and the use of trifluoromethanesulfonate ( triflate ) salts of scandium and the lanthanides as water-soluble Lewis acid catalysts is widespread. Beta-diketonate complexes and alkoxides have also come into use there are even applications of mischmetal in organic synthesis. [Pg.121]

Yao, Y.M., Xu, X.P., Liu, B. et al. (2005) Carbon-bridged bis(phenolato)lanthanide alkoxides syntheses, structures, and their application in the controlled polymerization of e-caprolactone. Inorganic Chemistry, 44, 5133. [Pg.346]

The strategy of metal alkoxides synthesis is entirely related to the electronegativity of the element concerned. Some electropositive metals, such as alkali metals, alkaline earth metals, and lanthanides, react directly with alcohols. But some less electropositive metals such as magnesium and aluminum require a catalyst (I or HgCy for successful reaction with alcohols. Use of electrochemical synthesis by anodic dissolution of some metals or metalloids (Sc, Y, Ti, Zr, Nb, Ta, Fe, Co, Ni, Cu, Pb, Si, Ge, etc.) in dry alcohol performs a promising procedure because it does not produce any by-products except hydrogen gas. Another applicable method for the synthesis of some alkoxides (B, Si, Ti, Zr, Hf, Nb, Ta, Fe, etc.) is the reaction of their chlorides with alcohols which require a base such as... [Pg.226]


See other pages where Applications of Lanthanide Alkoxides is mentioned: [Pg.229]    [Pg.246]    [Pg.229]    [Pg.246]    [Pg.150]    [Pg.230]    [Pg.265]    [Pg.163]    [Pg.257]    [Pg.35]    [Pg.152]    [Pg.235]    [Pg.190]    [Pg.232]    [Pg.713]    [Pg.40]    [Pg.177]    [Pg.1]    [Pg.184]    [Pg.197]    [Pg.459]    [Pg.466]    [Pg.278]    [Pg.156]    [Pg.109]    [Pg.49]    [Pg.473]   


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