Sonication accelerated formation of Mg-Al-phosphate layered double hydroxide via sol-gel prepared mixed metal oxides

Single-phase magnesium-aluminium layered double hydroxide (LDH) intercalated with dihydrogen phosphate was successfully produced by hydration of nanopowder of the respective mixed metal oxide (MMO) obtained using sol-gel based method followed by a two-step anion exchange hydroxide-to-chloride and chloride-to-phosphate. The MMO with the metal cation ratio of Mg/Al = 2:1 was prepared using the aqueous sol-gel method. Processes of the parent Mg2Al-OH LDH formation and the successive anion-exchanges, ОН- → Cl- and Cl- → H2PO4-, were considerably accelerated via the application of high-power (1.5 kW) ultrasound. The crystalline phases formed at all stages of the Mg2Al-H2PO4 LDH production were characterized using X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductive coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Based on the data of chemical analysis and the XRD data, the type of the intercalated phosphate anion was determined and the arrangement of this anion in the interlayer was modelled.publishe

Syntheses of symmetric and unsymmetric 2,6-bis(phosphino)phenols

Compounds bearing the structural motif of 2,6-bis(phosphino)phenol have been synthesized via two general methods. Double lithium-halogen exchange occurred in low-temperature reactions of O-protected (by methyl- or tetrahydropyranyl groups) 2,6-dibromo-4-methylphenol derivatives with BuLi (2 equivalents); quenching the reaction mixtures with chlorophosphines ClPR 2 (R = Ph, iPr) and corresponding O-deprotection yielded symmetrically substituted 2,6-bis(phosphino)phenols. Sequential incorporation of -PR2 functionalities was accomplished via single lithium-halogen exchange (1 eq. of BuLi) of tetrahydropyranyl-protected 2,6-dibromo-4- methylphenol followed by ClPR2 quenches, thus enabling the syntheses of unsymmetric 2,6-bis(phosphino)phenols. Such compounds were also obtained via sequential ortholithiations of tetrahydropyranyl-protected 4-tert-but ylphenol, followed by ClPR2 quenches. All of the new compounds have been characterized by spectrometric methods (1H and 31P NMR, and mass spectrometry). In addition, two of the compounds, 1-(diphenylphosphino) -3-(diphenylphosphoryl)-2-methoxy-5-methylbenzene (3a-ox) and 1,3-bis(diphenylphosphino)-2-methoxy-5-methylbenzene (6a) have also been characterized via single crystal X-ray diffraction experiments

Synthesis and characterisation of new molybdenum - oxo complexes containing diphenylphosphinylacetic acid and 2-(tert-butylsulphoxide)phenyldiphenylphosphine oxide as bidentate ligands

Reaction of the ligands diphenylphosphinylacetic acid Ph2P(O)CH2COOH (1) and 2-(tert-butylthio)phenyldiphenylphosphine oxide Ph2P(O)C6H4tBuS (2) with MoO2Cl2 , resulted in two complexes MoO2Cl2Ph2P(O)CH2COOH (3) and MoO2Cl2Ph2P(O)C6H4tBuS(O) (4). Complexes 3 and 4 were isolated and analysed by 1H NMR, 31P NMR and X-ray crystallography. Complex 3 crystallised with a molecule of the free ligand in a 1:1 ratio (3·1) and complex 4 crystallised with molecules of the solvent CH2Cl2 within the unit cell in a 2:1 ratio (4·0.5CH2Cl2). Tetrameric arrangements comprised of hydrogen bonds were observed in complexes 1 and 3. Complex 4 exhibited a seven-membered ring structure owing to the oxidation of the sulphide in 2 to sulphoxide and coordination of this ligand via the oxygen atoms to the molybdenum atom. © 2010 Elsevier B.V. All rights reserved

Synthesis, structures and ligating properties of 2,6-bis(phosphino)thiophenol derivatives

New t-butyl-aryl thioethers where the aryl group is 2,6-bis(phosphino)phenyl have been synthesized. The syntheses were completed via sequential ortho-lithiations of t-butylphenylsulfide, followed by chlorophosphine (ClPR2) quenches; symmetric (2,6-bis(diphenylphosphino)phenyl, (4a)) and unsymmetric (2-diisopropylphosphino-6-diphenylphosphino)phenyl, (4b) aryl groups were obtained. Treatment of 4a with Li or Na naphthalenide yielded 2,6-bis(diphenylphosphino)thiophenol 5. Reactions of 4a or 5 with NiCl2 · 6H2O yielded nickel bis(phosphinothiophenolate) 6. Compounds 4a,b, 5 and 6 were characterized by 1H and 31P NMR, and by mass-spectrometry. In addition, 4a, 5 and 6 were characterized by single crystal X-ray diffraction methods. © 2007 Elsevier B.V. All rights reserved