Alkoxide compounds

Metal alkoxide compounds, frequently represented as M(OR)x, where M is a metal and R is an alkyl group, are the most common precursors in sol-gel CSD processes and are also frequently used in chelate processes.3-12,30-34 Groups such as OR, which are bound to a metal center, are frequently referred to as ligands. Alkoxide compounds, including commonly used alkoxides such as... 

Chemical interactions, often called grafting, between the surface sites of a carrier and an organometallic or alkoxide compound govern the final particle size distribution for very small particles. 

Other reports confirm similar reaction of C02 with metal alkoxide compounds. Benzene solutions of the alkoxide compounds Ti(OBu")4, Zr(OBu")4, Zr(OEt)4, Nb(OEt)5, and Fe(OEt)3 were found to absorb carbon dioxide in various amounts (151). Only Zr(OBu")4 reacted with an amount approaching one equivalent per metal complex. The solution ir spectra indicate formation of coordinated organic carbonates. From this evidence, equilibrium formation of the species M(0R) 1(02C0R) under 1 atm of C02 is inferred. 

Enantiomer-selective polymerization of MBMA has also been attained by using the reaction products of chiral amine compounds, 168 and 169, with cyclohexylmagnesium bromide as initiator [242,243] and by using the aluminum porphyrin complex 170 in the presence of optically active aluminum alkoxide compounds 171a-e [244], In the latter systems, the enantiomer selection is based on enantiomer-selective coordination of the chiral aluminum compounds to MBMA as revealed by NMR analysis. With 171e as a catalyst, the ee of the unreacted monomer is 40% at 75% monomer conversion ratio in the polymerization at -70°C. 

Sodium and potassium form alkoxide compounds with the general formula M+ OR, in which R is a hydrocarbon group. Typically, sodium reacts with methanol ... 

What are alkoxide compounds In what sense are they organometallic compounds In what respects are they not organometallic compounds What does the reaction... 

While the investigation of Ce(IV) organyl [152] and alkoxide compounds [153] has attracted some attention, Ce(IV) amide chemistry was investigated in detail... 

Many alkoxide compounds of the heavier Group 2 elements are known, but most are either not volatile enough for use in CVD or are not thermally... 

Reaction of the metal ethoxide [M(OEt)2(HOEt)4] with the desired /3-diketone has been used as an anhydrous method to Group 2 /3-diketonates and mixed ligand/3-diketonate-alkoxide compounds. Presumably, the liberated HOR has a lower binding ability compared to liberated H20. Drake et al. have prepared [Sr3(tmhd)6(Htmhd)] and [Ba4(tmhd)8] by the reaction of Eq. (19).177 Equation (20) gives the generalized reaction for formation of mixed ligand compounds of formula [M(X)n(OR)2 ]) .184185... 

Group 2 metal alkoxide compounds are potentially suitable as CVD precursors, especially because hydrolysis and subsequent thermally induced dehydration are likely to lead to complete removal of the supporting ligands. There are examples of Group 2 metal alkoxide compounds that are claimed to have suitable volatility for CVD, but to our knowledge these have not been used successfully. However, Group 2 metal alkoxide compounds have found widespread application in solution routes to metal oxide materials, an area that has been reviewed.1... 

Alkoxide compounds show various coordination numbers and geometries which depend on the bulkiness of the ligand. Examples are the nearly planar 4-coordinate [Li(THF)]2V(2,6-diisopropylphenolate)4,7S square pyramidal (2,6-Ph2PhO)2V(py)3,76 and octahedral guaicolato [NafTHFlVGj. 77... 

The simplest lanthanide alkoxide compounds about which much is known are the iso-propoxides. There is some evidence that under mild conditions a simple Ln(OPr )3 can be... 

The carbyne complexes [Mo(=CBu )(SAr)3] (SAr = TMT, TIPT) have been synthesized by adding 3 eq of Li[SAr] to [Mo(=CBu )Cl3(dme)] (dme = dimethoxyethane). The analogous W derivatives were made by a slightly modified route (32). The initial aim was to probe the acetylene metathesis catalytic properties of the complexes [M ( Bu KSArlg] (M = Mo, W SAr = TMT, TIPT). However, none of the complexes were active for metathesis, which was in contrast to the high activity of the analogous alkoxide compounds for metathesis. This was attributed to the stronger electron donation power of thiolate, which reduces the electrophilic nature of the metal center (32). 

Although numerous alcohols are employed as solvents in sol-gel processing, for ferroelectric thin-hlm fabrication, 2-methoxyethanol (CH3OCH2CH2OH) has been the most extensively used. The starting reagents utilized are typically alkoxide compounds and the key reactions leading to the formation of the metal-oxygen-metal (M-O-M) network that is eventually formed are hydrolysis and condensation ... 

Hybrid, chelate, or molecularly modified precursor routes also utilize alkoxide compounds for the B-site species. Unlike true sol-gel processes, these routes rely on molecular modification of alkoxide compounds through reactions with other reagents, namely chelating ligands, such as acetic acid, acetylacetone, or amine compounds. Despite this difference, chelate processes stiU share several common attributes with methoxyethanol-based sol-gel processes, most importantly, the formation of oligomeric species during solution synthesis. 

---