Gallium isopropoxide: Synthesis,properties, “coordination polymerism”. New pentanuclear gallium oxoisopropoxochloride

Conditions for the synthesis of gallium isopropoxide (I) by anodic dissolution of the metal in i-PrOH (in the presence of Bu₄NBr supporting electrolyte) and by exchange reaction of GaCl₃ with i-PrONa were studied. In the latter case, the crude product was a waxy substance (II) infinitely soluble in the alcohol and hydrocarbons and containing 12–30% Cl, which cannot be removed by adding an excess of i-PrONa due to the formation of insoluble NaGa(OPr-i)₄. During 1.5–2 months, II is solidified to give non-melting nonvolatile amorphous product (III) poorly soluble in the alcohol. Upon heat treatment of II in vacuum, compound I is distilled off as an oily liquid consisting, according to mass spectrometry, of [Ga(OPr-i)₃]₂ dimer molecules. It can be retained for a long period of time in the presence of the [Ga(OPr-i)₃]₄ tetramer crystals. The existence of oligomeric molecules of different size up to polymers (“coordination polymerism”) in the materials is related to the possibility of tetrahedral or octahedral coordination of the metal atom. From concentrated solutions of components, the oxoalkoxochloride [Ga₅(µ₅-O)(µ-OPr-i)₈Cl₅] (IV) is crystallized. Its molecule is a flattened tetragonal pyramid. The equatorial plane formed by four gallium atoms has the µ₅-O group at the center. The axial Ga atom has an octahedral coordination. All eight sides of the pyramid are drawn together by the µ-OPr-i groups, and the chlorine atoms occupy the terminal positions. (CIF file CCDC no. 693282.)     

On the interaction of tetraethoxosilane with metal alkoxides: Sol-gel synthesis of alkaline-earth metal silicates

Physicochemical analyses (solubility method, conductometry, and IR spectroscopy) revealed no complex formation in M(OR)_n-Si(OR)₄-ROH systems (M = Na, Ba, Al; R = Et, Prⁱ), unlike in the systems containing alkoxides of two metals. IR and NMR spectroscopy showed that Si(OR)₄ became reactive only due to microhydrolysis, which is accompanied most likely by the formation of intermediates (asymmetric molecules [Si(OH)_n(OR)_{4 ? n} ]). The hydrolysis was studied for model systems M(OEt)₂ ? si(OEt)₄ (M = Ba, Ca), and conditions for the synthesis of silicates were optimized.     

Electrosynthesis of tin(II) alkoxides

The anodic dissolution of tin metal in absolute alcohols yields oxoalkoxides with the general formula Sn₆O₄(OR)₄ (R = Me (1), Et (2), i-Pr (3)) and orthoalkoxides with the general formula Sn(OR)₂ (R = n-Bu (4), C₂H₄OMe (5)). According to X-ray crystallographic data, the molecule of Sn₆O₄(OEt)₄ (2) is an octahedral [Sn₆] cluster with alternating oxo and OEt groups on its faces. The mass spectra of 1 and 2 indicate the presence of fragments of the hexanuclear oxoalkoxides.     

3,3-Dimethyl-1-(trifluoromethylsulfonyl)-1,3-azasilolidine

Russian Journal of General Chemistry -     

Synthesis of 4-acyl(alkoxycarbonyl)-5-fluoroalkyl-3,5-dihydroxyfuran-2(5H)-ones

4-Acyl(alkoxycarbonyl)-5-fluoroalkyl-3,5-dihydroxyfuran-2(5H)-ones were obtained for the first time by the reactions of fluoroalkyl-containing 1,3-diketones and 3-oxo esters with oxalyl chloride.     

Chiral complex-forming and trans-phase transfer agents. 7. Complex forming properties of podands based on 1,4∶3,6-dianhydro-D-mannitol

In their complexation with alkali metal picrates, podands prepared from l,43,6-dianhydro-D-mannitol display affinity to Na and Li cations but virtually do not bind K ions. It was shown using the¹H NMR method that these podands form complexes with -phenylethylammonium perchlorate, the composition and strength of which depends on the nature of the side-chains of the podand. The podands studied are not capable of participating in the enantioselective transfer of the chiral substrate from the aqueous phase into chloroform.For previous communication, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2501–2504, November, 1989.     

Reactivity of Al(III) complexes with substituted phthalocyanines

The results of a study of reactivity of Al(III) complexes with acido ligands (Cl^?, OH^?) and substituted phthalocyanine, containing 4 and 8 substituents (Cl, Br, NO₂ or COOH) in different positions of annelated benzene residues, are reviewed. Reactivity of coordinated phthalocyanines is studied by quantum-chemical and spectrophotometric methods for acid-base reactions and reactivity of coordination core is estimated by chemical kinetics methods using reactions of dissociation at the Al-N bonds. The Hammett-Taft correlation equations are derived for mono-and diprotonated tetrasubstituted phthalocyanines of Al(III) with positive ρ values of 10.2 and 59.8, respectively     

Conformational analysis of N‐phenyl‐ and N‐trifyl‐4,4‐dimethyl‐4‐silathiane 1‐sulfimides

N‐Substituted 4,4‐dimethyl‐4‐silathiane 1‐sulfimides [R = Ph ( 1 ), CF₃ ( 2 )] were studied experimentally by variable temperature dynamic NMR spectroscopy. Low temperature ¹³C NMR spectra of the two compounds revealed the frozen ring inversion process and approximately equal content of the axial and equatorial conformers. Calculations of the 4‐silathiane derivatives 1 , 2 and the model compound [R = Me ( 3 )] as well as their carbon analogs, the similarly N‐substituted thiane 1‐sulfimides [R = Ph ( 4 ), CF₃ ( 5 ), Me ( 6 )] at the DFT/B3LYP/6–311G(d,p) level in the gas phase and in chloroform solution using the PCM model at the same level of theory showed a strong dependence of the relative stability of the conformer on the solvent. The electronegative trifluoromethyl group increases the relative stability of the axial conformer. Copyright © 2010 John Wiley & Sons, Ltd.     

Decomposition of solid NaCl-AgCl solutions

The dependence of the microhardness on the aging time for NaCl-AgCl solid solutions was found at room temperature for solutions of between 10 and 30 mole% AgCl in NaCl. During decomposition under these conditions the microhardness passes through a maximum. The relationship between the change in the microhardness and the changes in the intensity distribution of x radiation scattered by the decomposing solid solution has been established.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 11, pp. 18–22, November, 1970.