0000000000805474
AUTHOR
Umberto Russo
Synthesis and chemico-physical characterization of tin(IV) complexes with some crown ethers
Abstract Some neutral adducts of diorganotin(IV) perchlorates and thiocyanates with three crown-ethers have been synthesised; they are of the type Me 2 SnX 2 L m · n H 2 O where m = 1 or 2, n = 2 or 4, X = ClO 4 or NCS, and L = 18-crown-6, 15-crown-5, and 12-crown-4. The values for m and n have been correlated with the coordinating ability of the two anions and with the steric hindrance by the crown ether molecules. From infrared and Mossbauer data, an octahedral coordination geometry is proposed for all the complexes. The Mossbauer parameters are discussed in terms of the electronegativity of the ligands on the tin(IV) center and of the distortions produced in the coordination polyhedra by…
Synthesis and x-ray crystal structure of dimethyltin(IV) dithiocyanate bihydrate adduct with a crown ether
Me 2 Sn(NCS) 2 (OH 2 ) 2 . 18-crown-6 cristallise dans P2 1 /n avec Z=2; affinement jusqu'a R=0,058
The blue enamels in the baroque decorations of the churches of Palermo, Sicily: Fe2+-coloured glasses from lime kilns
Deep blue glasses coloured by octahedral Fe 2+ cations are often reported as textbook examples of blue pigmentation. However, despite the possibility of laboratory synthesis under reducing conditions, to date there are no well-reported occurrences of their production and use in the past. A thorough historical, ethnographic, mineralogical, and chemico-physical investigation of the 'smaltini di calcara' from several baroque churches in Palermo, Sicily, has revealed that the blue enamels widely used for altar decorations in the 17th and 18th centuries are actually a unique case of ancient blue glasses pigmented by divalent iron cations in distorted octahedral coordination. This mixed-alkali gl…
Radiofrequency ablation of osteoid osteoma
Osteoid osteoma is a benign bone neoplasm with a reported incidence of 2-3% among all bone primary tumors. Although it is a small and benign lesion, it is often cause of patient complaint and discomfort. It is generally characterized by a long lasting, unremitting pain that typically exacerbates at night, often leading to sleep deprivation and functional limitation of the skeletal segment involved, with a significant reduction of patient daily life activities and consequent worsening of the overall quality of life. Over decades, complete surgical resection has represented the only curative treatment for symptomatic patients. In the last years, new percutaneous ablation techniques, especiall…
INTERACTIONS OF ORGANOTIN(IV) HALIDES WITH REDUCED GLUTATHIONE IN AQUEOUS-SOLUTION
Abstract Glutathione (GSH) is a compound extremely common among many living organisms in which it plays a fundamental role in the processes of detoxification. Also, organotin(IV) derivatives are more and more commonly used in technological processes or as antitumor drugs. So it seemed interesting to investigate the possible interactions between GSH and organotin compounds in water. Particularly, it has been studied because of its role in the organic radicals linked to the tin center on the stoichiometry and the structure of the adducts. Information was obtained following the reaction between Me n SnCl 4-n (n = 1 to 3) and GSH by Mossbauer and NMR spectroscopies on the assumption that change…
Synthesis and mössbauer studies of some aquo complexes of tin(IV) with crown ethers
Abstract The preparation, characterization, and 119Sn Mossbauer spectra of a number of tin(IV) complexes with cyclic polyethers are presented. With tin(IV) chloride and methyltin(IV) trichloride, 1:1 and 2:1 metal-to-crown-ether complexes are formed, while dimethyltin(IV) dichloride forms only 2:1 complexes; in every case, two water molecules are present in the solid state structure. An octahedral coordination geometry around the tin(IV) center is proposed on the basis of Mossbauer and IR spectra.