3147-53-3Relevant articles and documents
Mono- and di-anionic coordination modes of arylazosalicylates in their bis(η5-cyclopentadienyl)titanium(IV) complexes: Syntheses and crystal structures
Basu Baul, Tushar S.,Manne, Rajesh,Tiekink, Edward R.T.
, p. 469 - 480 (2019)
The bis(η5-cyclopentadienyl)titanium(IV) complexes of 5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoic acids (H2LXASA) where the aryl group is an X-substituted phenyl ring such that X = CH, COEt, CMe, CF, CCl, CBr and N have been synthesised. Two types of titanium(IV) compounds viz. (i) [Ti(η5-C5H5)2(O2CC6H3(OH-2)(N[dbnd]NC6H4(H-4)-5))2] (3) and [Ti(η5-C5H5)2(O2CC6H3(OH-2)(N[dbnd]NC6H4(OC2H5-4)-5))2] (4), and (ii) [Ti(η5-C5H5)2(O2CC6H3(O-2)(N[dbnd]NC6H4(CH3-4)-5))] (5), [Ti(η5-C5H5)2(O2CC6H3(O-2)(N[dbnd]NC6H4(F-4)-5))] (6), [Ti(η5-C5H5)2(O2CC6H3(O-2)(N[dbnd]NC6H4(Cl-4)-5))] (7), [Ti(η5-C5H5)2(O2CC6H3(O-2)(N[dbnd]NC6H4(Br-4)-5))] (8) and [Ti(η5-C5H5)2(O2CC6H3(O-2)(N[dbnd]NC5H4(N-4)-5))] (9) were isolated and characterised by IR, 1H and 13C NMR spectroscopic techniques. The crystal and molecular structures of 3–9 have been determined by single crystal X-ray crystallography. Compounds 3 and 4 conform to the formula Cp2Ti(HLXASA-κO)2 with a monodentate carboxylate ligand while those of 5–9 conform to Cp2Ti(LXASA-κ2O1,O2) with the dianions chelating the titanium atoms via carboxylate-O and hydroxy-O atoms. The common feature of the molecular structures is the adoption of distorted tetrahedral geometries based (Cp)2O2 donor sets. Hydroxyl–O–H…O(carbonyl) bonding leads to supramolecular chains in the crystal of 4 but, these are absent in 3. Persistent Cp–C–H…O(carbonyl) interactions, with the carbonyl atoms accepting two or three such interactions, lead to supramolecular chains with helical (5, 7 and 8) or linear (6 and 9) topologies; C–X…π interactions also play an important role in the packing of 6–8.
Azo Derivatives of Pyrocatechol, Resorcinol, and Salicylic Acid as Collectors for Sulfide Ore Flotation
Baigacheva, E. V.,Gogolishvili, V. O.,Gusev, V. Yu.
, p. 1734 - 1744 (2020/02/25)
Heterocyclic and aromatic azo derivatives of pyrocatechol, resorcinol, and salicylic acid have been investigated as collectors for the flotation of sulfide ores. The acid-base properties of the compounds were studied, their solubility in an alkaline solution was determined. It was established that the fixing of reagents on the surface of the ore occurs mainly by the chemical mechanism. Adsorption constants were calculated. It was found that most of the studied reagents exhibit collective properties with respect to sulfide copper—nickel ore. The use of mixtures of azo compounds with potassium butyl xanthogenate leads to an increase in the degree of extraction of nickel and copper, as well as the quality of the concentrates, in comparison with one butyl xanthogenate.
Novel salicylazo polymers for colon drug delivery: Dissolving polymers by means of bacterial degradation
Saphier, Sigal,Karton, Yishai
scheme or table, p. 804 - 815 (2011/02/26)
Novel azo polymers were prepared for colonic drug delivery with a release mechanism based on structural features of azo derivatives designed for rapid bacterial degradation leading to soluble polymers. Two Salicylazo derivatives were prepared and conjugated as side chains at different ratios to methacrylic acid-methyl methacrylate copolymers (Eudragits). The azo compounds were designed to have a hydrophilic and a hydrophobic part on opposite sides of the azo bond. Upon reduction of the azo bonds, the hydrophobic part is released, resulting in a more water soluble polymer. The solubility of the polymeric films was studied relative to Eudragit S known to dissolve toward the end of the small intestine. One of the two azo derivatives prepared gave rise to polymers, which showed reduced solubility relative to Eudragit S. These polymers were subjected to reduction tests in anaerobic rat cecal suspensions by following the release of the hydrophobic product. Reduction rate was found to be rapid, comparable to that of Sulfasalazine. Studies on the azopolymeric films in anaerobic rat cecal suspensions, showed that these polymers dissolve faster than in sterilized suspensions. Solid dosage forms may be coated with these polymers to provide an efficient delivery system to the colon with a rapid release mechanism.
