Reactions of halometal alkoxides

Aryl thenyl and aryl aryl--thienylmethyl sulfides have been obtained by the action of oxalic acid esters on an equimolecular mixture of bromomagnesium thienyl or aryl -thienyl carbinolates and bromomagnesium thiophenolates (or thionaphtholates). Derivatives of the sulfides, sulfoxides and sulfones, are also described.For part XX, see [9].     

Reactions of halogen metal alkoxides

The study of the thermal stability of halogen-magnesium alkoxy-carbinolates was continued. The data obtained led to the development of procedures for the synthesis of esters of -oxo and of -hydroxy-acids containing the thienyl radical. An intramolecular hydrogen bond between the sulfur atom and the hydrogen of the hydroxyl group in esters of (5-bromothienyl-2)glycolic acid was revealed. The presence of this bond was confirmed by infrared spectroscopic data and by the results of the investigation of the esters of (thienyl-3)- and (4-bromothienyl-3)glycolic acids.For part XXII, see [4].     

Reactions of halogen metal alkoxides

The study of the thermal stability of halogen-magnesium alkoxy-carbinolates was continued. The data obtained led to the development of procedures for the synthesis of esters of α-oxo and of α-hydroxy-acids containing the thienyl radical. An intramolecular hydrogen bond between the sulfur atom and the hydrogen of the hydroxyl group in esters of (5-bromothienyl-2)glycolic acid was revealed. The presence of this bond was confirmed by infrared spectroscopic data and by the results of the investigation of the esters of (thienyl-3)- and (4-bromothienyl-3)glycolic acids.     

Reactions of aluminum alkoxides with esters of inorganic acids

Russian Chemical Bulletin -     

Reactions of substituted pyridines and their N-oxides with ethanolic sodium hydroxide and various alkoxides

2-Benzoylpyridine 1-oxide with ethanoiic sodium hydroxide yielded acyl nucleophilic displacement products and a redox product, 2-(α-hydroxybenzyl)pyridine. 3-Benzoylpyridine 1-oxide under the same conditions yielded only a reduction product, 3-(α-hydroxybenzyl)-pyridine 1-oxide, whereas 4-benzoylpyridine 1-oxide yielded only a redox product, 4-(α-hydroxy-benzyl)pyridine. The redox reaction which is promoted by base occurs with an α-hydroxybenzylpyridine 1-oxide which results from a carbonyl reduction of the starting material. The benzoyl-pyridine 1-oxides reacted qualitatively the same with sodium ethoxide or isopropoxide as they did with ethanoiic sodium hydroxide, but they reacted differently with potassium t-butoxide or aluminum isopropoxide. The cyano- and benzenesulfonyl-pyridine 1-oxides reacted with ethanolic sodium hydroxide to yield pyridinecarboxylic acids and 1-hydroxypyridones, respectively.     

Rhenium alkoxides

The data on synthesis of individual and heterometallic alkoxide and oxoalkoxide derivatives of rhenium are summarized. Their structures are considered, characteristic features and peculiarities of the structures are analyzed. Data on the thermal decomposition of rhenium alkoxides and its application for the preparation of rhenium-based metallic and oxide materials are given. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2177–2188, October, 2005.     

Electrochemical synthesis of metal alkoxides. Prospects of commercial alkoxides production

A production method of Ti, Zr, Nb, Ta, Y, Sn, Cu, Ge, Mo, W and some other metals alkoxides at their anode polarization in alcohols (methanol, ethanol, i-propanol, butanol, methoxy-ethanol) in the presence of an electroconductive additive has been developed.As a result of theoretical and experimental studies and engineering development, a universal low-waste technological processes of the electrochemical production of the above high purity alkoxides have been established.Metal efficiency coefficient in the electrosynthesis process is 0.85–0.90, current efficiency is 75–80%, and specific power consumption is within 5–10 kW-h/kg range.The total of impurities provided by this technology does not exceed 10^–3% mass.The developed electrochemical technology has been realized at a pilot-commercial scale at AO NIPIM plant (Russia, Tula) in order to manufacture a high purity titanium tetrabutoxide at 1.5–2.0 t/year plant operation the actual advantages of the electrochemical technology comparing to a traditional chemical one have been revealed.A considerable simplification of the developed electrochemical technology has been achieved at the anode polarization of metals in the methxyethanol due to elimination from the diagram scope of units for the alkoxides separation from after electrolysis solutions and recovery of unreacted raw components.     

Oximate-substituted zirconium alkoxides

The reaction of acetoxime, ethyl methyl ketoxime or cyclohexanone oxime with zirconium iso-propoxide gave dimeric alkoxo oximate derivatives [Zr(OiPr)(oximate)?]?. The oximate ligands are side-on coordinated and the alkoxo groups bridge the two metal centres. NMR spectroscopy revealed dynamic behaviour of the compounds in solution. When exposing a reaction mixture of zirconium butoxide and cyclohexanone oxime to ambient moisture, the oxo-alkoxo derivative Zr?O(OBu)?(ON=C?H??)? was obtained.     

Synthesis and characterization of a series of rubidium alkoxides and rubidium-titanium double alkoxides

This report investigates the structural aspects of the products isolated from the reactions of a series of titanium alkoxides [[Ti(OR)4]n n = 2, OR = OCH2C(CH3)3 (ONep) (1); n = 1, OC6H3(CH3)2-2,6 (DMP) (2)] with rubidium alkoxides [[Rb(OR)]infinity where OR = (ONep) (3), (DMP) (4), and OC6H3(CH(CH3)2)2-2,6 (DIP) (5)]. The resultant double alkoxides were determined by single crystal X-ray diffraction to be [Rb(mu-ONep)4(py)Ti(ONep)]2 (6), [Rb(mu-DMP)Ti(DMP)4]infinity (7), and [Rb(mu-DMP)2(mu-ONep)2Ti(ONep)]infinity (8). Compound 1 is the previously reported dinculear species with trigonal bipyramidal Ti metal centers whereas compound 2 is a monomer with a tetrahedral Ti center. Suitable X-ray quality crystals of 3 were not isolated. Compounds 4 and 5 demonstrate extended polymeric networks with Rb coordination ranging from two to five utilizing terminal mu- and mu3-OR ligands and pi-interactions of neighboring OAr ligands. The double alkoxide 6 revealed a simple tetranuclear structure with mu-ONep acting as the bridge, terminal ONep ligands on the Ti, and one terminal py on the Rb. For 7 and 8, the pi-interaction facilitated the formation of extended polymeric systems. All complexes were further characterized by FT-IR and multinuclear NMR spectroscopy.     

Halogen-containing tetrametallic aluminium alkoxides

New halogen-containing tetrametallic aluminium alkoxides of formula [Al{(mu-OEt)2AlMeCl}3] ( 2-cis; 2-trans), and [Al{(mu-OEt)2AlBr2}3] ( 4), have been synthesized by combining Al(OEt)3 and Me2AlCl (for 2) or EtAlBr2 (for 4). They were fully characterized by (1H, 27Al) NMR, IR, mp, elemental analysis, and single-crystal X-ray diffractometry. The chloride analogue of 4, [Al{(mu-OEt)2AlCl2}3] ( 3), prepared previously using a different route, was also prepared here by combining Al(OEt)3 and EtAlCl2.     

The catalytic activity of alkali metal alkoxides and titanium alkoxides in the hydrosilylation of unfunctionalized olefins

The catalytic activities of titanium alkoxides and alkali metal alkoxides for hydrosilylation of unfunctionalized olefins have been studied. Titanium(IV) alkoxides showed excellent catalytic activity, while alkali metal alkoxides have low catalytic activity for the hydrosilylation of olefins. However, by using titanocene dichloride as an additive, alkali metal alkoxides showed also excellent catalytic property for hydrosilylation. In comparison with titanium alkoxides, no α-adduct was obtained by using alkali metal alkoxides/Cp₂TiCl₂ as catalysts.     

Thermal analysis of some metal alkoxides

The thermal decomposition of AI(OPrⁱ)₃, Ca(OEt)₂ and Mg(OEt)₂ has been studied using differential thermal analysis and thermogravimetric techniques. The decomposition products have been isolated and identified by gas chromatography and mass spectrometry. Probable routes for the thermal decomposition of these alkoxides have been proposed.     

钛醇盐电化学合成的研究

采用钛金属为“牺牲”阳极,首次在无隔膜电解槽中,电化学一步法制备了纳米TiO~2前驱体钛醇盐Ti(OEt)~4,Ti(OPr-i)~4,Ti(OBu)~4。产物通过元素分析、红外光谱(FT-IR)、拉曼光谱进行表征。电化学一步法直接制备纳米材料前驱体钛醇盐,克服了传统化学方法合成金属醇盐步骤多、产率低、纯度达不到要求及后续分离繁琐等缺点。本文同时讨论了影响电合成钛醇盐的关键因素及可能的反应机理,实验表明钛在醇溶液中呈点蚀行为,钛醇盐卤化物Ti(Ⅲ)(OR)~nBr~m在阳极形成,然后被氧化为Ti(Ⅳ)(OR)~nBr~m,这种物质在阴极上ROH参与下被还原生成钛醇盐Ti(OR)~4,钛阳极表面拉曼光谱证实了上述观点。防止阳极钝化,温度控制在50～60℃之间,彩有机胺溴化物为导电盐,可以提高电合成收率。     

Oxozirconium(IV) alkoxides

Oxozirconium(IV) alkoxides of the type ZrO(OR)₂·ROH and ZrOCl(OR)·2 ROH, where R is methyl, ethyl, and isopropyl, and ZrO(OCMe ₃)₂·0.5Me ₃COH and ZrOCl(OCMe ₃)·1.5Me ₃COH have been prepared by the reaction of dichloroxozirconium(IV)-2-acetic acid with corresponding alcohols in the presence of appropriate amounts of piperidine. The alkoxides have been isolated and characterised through infrared, thermal and conductance studies.     

Dimethylaluminum and gallium amino alkoxides

An S,S′-thioether—thioester chelating ligand [7,8-μ-SCH₂C(O)S-7,8-C₂B₉H₁₀]⁻ (L₁), incorporating the unit [—(C)₂B₉H₁₀]⁻ has been synthesized. Reactions have been conducted with RhCl(PPh₃)₃ and PdCl₂(PPh₃)₂ complexes in ethanol. With Rh, L₁ maintains its original cyclic nature and most probably chelation via thioether—thioester takes place. The carborane negative charge may stabilize this original thioether—thioester complex. The other two Rh positions are occupied by two PPh₃ ancillary ligands forming [Rh(L₁)(PPh₃)₂]. The reaction of L₁ with Pd induces ligand modifications and the cyclic nature of L₁ is lost. A transesterification process leading to a dianionic ligand L₂, [7-S-8-SCH₂C(O)OCH₂CH₃−7,8-C₂B₉H₁₀]²⁻ has taken place. In this way L₂ is capable of compensating the dipositive Pd charge. The other two Pd positions are occupied by two PPh₃. This reaction has been extended to methanol and isopropanol solvents. The crystal structure of [Pd(L₂)(PPh₃)₂] has been determined.