A 3D-QSAR approach based on the electrostatic surface of molecules was used for the ambergris odour, and it showed a cross validation coefficient of 0.8.

Prolonged storage of solutions in the Al(OPri)3–Ta(OPri)5–iPrOH system containing additional nPrOH leads to crystallization with minor yields of a new aluminium oxopropoxide, Al11O6(OPrn)10(OPri)10(OR)(ROH)2 (R=Pri, Prn) (1). Interaction of Al(OPri)3 with Mg(acac)2 (in a 1:1 ratio) in toluene on refluxing leads to formation of Al5Mg4O3(OH)3(OPri)8(acac)6·0.5PhMe (2) in minor yields. Both molecules contain two pentanuclear cores [M5(μ4-O)(μ3-O)(μ-OX)6(Y)4] (X=H, Prn, Y=OPri, acac/2) and differ only in the manner in which they are attached to each other, i.e. via the central [Al(μ3-O)2(μ-O)2(OR)] unit in 1, and via a common [Al–(μ3-O)] edge and an additional (μ-OH)-group in 2. The core structures in the molecules of aluminium and iron oxoalkoxides are discussed.

New homo- and heterometallic [M(OR)(3)](m) and [ZnM2(OR)(8)](m) species (M=Al, Ga; R=C2H4OMe, C2H4NMe2) have been prepared and characterised by elemental analysis, electrospray mass spectrometry, FT-IR and multinuclear NMR. Hydrolyses of the heterometallic compounds were investigated and the particle sizes were determined. The thermal behaviour of the hydrolysed products was studied by TGA/DTA and the nature of the phases was analysed by powder X-ray diffraction. Various sol-gel processing parameters were studied in order to stabilise nanosized colloidal suspensions for access to thin films by spin coating. [ZnGa2(OC2H4OMe)(8)](2) was the best candidate for sol-gel processing, allowing crystalline ZnGa2O4 solids to be obtained at 300degreesC. Films, obtained on glass and MgO substrates, were transparent (>95%) and characterised by UV-visible and X-ray photoelectron spectroscopies, tapping mode AFM, SEM, EDX and X-ray diffraction.

Functional indium [In(OR)3]m alkoxides (R=C2H4OMe, C2H4NMe2) have been obtained by alcoholysis of In[N(SiMe3)2]3 and characterised by elemental analysis, FT-IR and NMR spectroscopy. The 2-dimethylaminoethoxide was characterised by X-ray diffraction. It corresponds to the association of two InO6 octahedra giving the unsymmetrical dimer [In2(μ,η1-OR)(μ,η2-OR)(η2-OR)3(η1-OR)] (2). 2 was used as a pincer ligand toward Cu(acac)2.

The crystal structures of LiTa(OMe)(6) (I), LiTa(OEt)(6) (II), BeTa2(OPr-iso)(12) (III), MgTa2(OEt)(12).2EtOH (IV), SrTa2(OPr-iso)(12).2iso-PrOH (V), BaTa2(OPr-iso)(12).2iso-PrOH (VI), and LaTa2(OPr-iso)(13) (VII) were studied. Structure I is composed of infinite chains of alternating LiO4 tetrahedra and TaO6 octahedra with shared edges parallel to one of the crystallographic axes. In the linear structure III, the central BeO4 tetrahedron shares edges with two TaO6 octahedra. Molecules IV-VII contain chains of three edge-sharing octahedra; in linear molecule IV, the magnesium atom coordinates two solvation molecules of alcohol trans to each other, whereas in angular isomorphous molecules V and VI, they are cis to each other. In asymmetric molecule VII, the central LaO6 octahedron shares a face with one peripheral TaO6 octahedron and an edge with the other. All alkoxotantalates under consideration are isomorphous with corresponding alkoxoniobates. The mutual arrangement of three metal atoms in the chains as a function of the structure of the coordination polyhedron of the central atom is discussed. Complex III was obtained for the first time by the exchange reaction of BeCl2.2THF with NaTa(OPr-iso)(6) in an isopropanol solution, and its mass spectrum was measured.

Heterometallic [ZnM2(OR)(8)](m) species (M = Al, Ga; R = C2H4OMe, C2H4NMe2) were prepared and characterized by elemental analysis, FT-IR and multinuclear NMR (H-1, C-13, Al-27). Their Hydrolysis was investigated. The powders were analysed by FT-IR, TGA/TDA and XRD. [ZnGa2(OC2H4OMe)(8)](2) allowed to obtain ZnGa2O4 at 300degreesC. Particles size in solution and aging phenomena were analysed. Stable colloidal suspensions (150 - 200nm) for elaboration of thin films by spin-coating techniques were obtained. These films transparent and were characterized by XRD, XPS, TMAFM, SEM, EDAX and UV-V spectroscopy.

The review provides a description of main events in the development of chemistry of metal alkoxides in Russian and summarizes the results obtained by the authors. The studies of solubility and vapor pressure in the M(OR)(n)-ROH (R = Li, Mg, Ca, Sr, Ba, Tl) systems permitted the determination of the composition of the solvates formed and the optimization of the isolation conditions for distinct derivatives. The electrochemical synthetic approach to the alkoxide and 2-methoxyethoxide derivatives of III-VIII Group elements has been elaborated. Improvement of the MCln with NaOR metathesis conditions led to practically quantitative yields of alkoxides.The examples of the structures of polynuclear oxoalkoxides, earlier erroneously considered to be orthoderivatives, i.e. 'M(OR)(n)', are given. It has been stated that among the alkoxoderivatives of Zr and I-If these are only M(OC2H4OMe)(4) and M(OR)(4) . ROH (R = Pr', Bu') that exist as individual compounds, while the samples of those with different R contain oxocomplexes of M3O(OR)(10) and M4O(OR)(14) composition. The questions connected with the origin of oxogroups in the molecules of alkoxides and their influence on the properties of the samples are discussed. The irreproducibility of the physicochemical constants for the samples (physical state, melting points, solubility in alcohols, intensity of coloration) is caused by different 'chemical' (synthetic procedures, isolation conditions) and thermal prehistory and storage times; it originates from the difference in their molecular composition (different fractions of different types of oligomeric and polymeric [M(OR)(n)](m) and MxOy(OR)(z) aggregates).Formation of bimetallic alkoxides is studied using the plotting of 20 degrees C solubility isotherms in M(OR)(n)- M'(OR)(m)-Solvent systems. Different kinds of systems are considered and the composition and structure of bimetallic complexes and oxocomplexes, originating from their decomposition, are described. Decomposition of alkoxomolybdates and -tungstates in solutions may result in crystallization of complex oxides as the final products. The example of MTiO3 (M = Mg, Ba) oxide preparation is discussed as most illustratively demonstrating the need in studies of metal alkoxides interaction in solution for the optimization of synthesis of oxides by the sol-gel technique. (C) 1998 Elsevier Science Ltd. All rights reserved.

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