1,721,043 research outputs found
Weak Interactions Involving Aryl -Systems and Halogen Atoms in the Crystal Structures of Phosphorus Derivatives of Betti Bases.
No full textPlatinum complexes with the novel ligand diethyl [(methylsulfinyl)methyl]phosphonate (SMP): Solid-state characterization of potassium trichloro(SMP)platinum(II) which, in solution, gives dichloro(SMP)-platinum(II) and potassium chloride
No full textPhosphonate ligands have been employed in the synthesis of platinum complexes, which are active against bone tumors. The stability of a new compound of this family, [PtCl2(SMP)] {1; SMP = diethyl[(methylsulfinyl)methyl]phosphonate), has been investigated in water and acetone. The compound is stable in aqueous solution where it undergoes only partial solvolysis that is completely repressed by addition of free chloride ions. However, crystallization of 1 from water/acetone/chloroform (0.2:1:1, v/v/v) containing an equimolar amount of KCl affords a new compound containing monodentate SMP {K[PtCl3(SMP-S], 2}. Dissolution of 2 in water or acetone restores 1. The driving force in the formation of 2 appears to be the network of electrostatic interactions between cations and complex anions in the solid state. It is not only the detached P=O oxygen atom, but also the oxygen atom bound to the sulfur atom and a coordinated chloride ligand of the same platinum unit that interact rather strongly with the cation. It is expected that the same reaction (partial detachment of the phosphonate and anchoring of the cation) can take place in hypercalcaemic districts associated to bone tumors
Self-assemblies of chiral p-haloaryl sulfoxides through C-H center dot center dot center dot O short contacts and halogen involving interactions
No full textSingle crystal X-ray structure determination of four crystals of alkyl or aryl p-haloaryl sulfoxides is reported. Intramolecular short contacts between the ortho-hydrogen of the aryl ring and the oxygen of the sulfinyl group were found to determine the conformations of the sulfoxides. On the other hand, in the absence of classical hydrogen bond donors, crystal packing arrangements are the results of intermolecular aryl hydrogen-oxygen short contacts and of interactions involving halogen atoms. From a comparison of the structures of the investigated sulfoxides with other literature data, the crystal packings of these types of compound appear to derive from a complex balance among different interactions
“Oxidation of Natural Targets by Dioxiranes. 6.On the Direct Regio- and Siteselective Oxyfunctionalization of Estrone and of 5α-Androstane Steroid Derivatives.”
No full textUsing methyl(trifluoromethyl)dioxirane (1b), 3b,6a,17b-triacetoxy-5a-androstane (6) could be selectively
transformed into its C-14 hydroxy derivative (7) and into the valuable C-12 ketone steroid (8),
in high yields under mild reaction conditions. Similarly, the oxidation of 3a-estrone acetate (4) with
1b was carried out to yield selectively the steroid C-9 hydroxy derivative (5). The high regio- and siteselectivity
attained demonstrates that the powerful dioxirane 1b is the reagent of choice to synthesize
valuable oxyfunctionalized steroid derivatives
Crystal-chemical investigation of Al2(PO4)(OH)3 augelite from Rapid Creek, Yukon, Canada.
No full textThe structural characterization of Al-2(PO4)(OH)(3) augelite, a natural orthophosphate coming from Rapid Creek, Yukon, Canada, was carried out by means of a multi-methodological approach based on WDS-EMPA chemical analysis, single crystal X-ray diffraction, and infrared spectroscopy. The structure was solved in the C2/m monoclinic space group, with the following unit cell constants: a = 13.0740(10), b = 7.9690(7), c = 5.0910(7) angstrom, beta = 112.282(5), V = 490.81(9) angstrom(3). Phosphorus atoms display tetrahedral (PO4) coordination, while aluminum cations display octahedral and unusual five-fold coordination. The framework of the mineral can be viewed as the repetition of cationic arrays made up by AlO6/AlO5 polyhedra, bridged by PO4 groups, and further joined by O-H..O hydrogen bonds: such interactions were also correlated to IR spectroscopy analysis, by means of Libowitzky formula applied on OH stretching vibration
Stability of the complex [PtCl2(SMP)] in solution and X-ray analysis of the unexpected species K[PtCl3(SMP)].
No full textA new dinuclear platinum complex with a nitrogen-containing geminal bisphosphonate as potential anticancer compound specifically targeted to bone tissues
No full textPlatinum Complexes with the Novel Ligand Diethyl [(Methylsulfinyl)- methyl]phosphonate (SMP): Solid-State Characterization of Potassium Trichloro(SMP)platinum(II) which, in Solution, Gives Dichloro(SMP)- platinum(II) and Potassium Chloride
No full textA Raman study of chalcogen species in sodalite-group minerals from the volcanic rocks of Latium (Italy)
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