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.
Tweaking the affinity of aryl-substituted diazosalicylato- and pyridine ligands towards Zn (II) and its neighbors in the periodic system of the elements, Cu (II) and Cd (II), and their antimicrobial activity
Basu Baul, Tushar S.,Nongsiej, Khrawborlang,Lamin Ka-Ot, Augustine,Joshi, Santa Ram,Rojas León, Irán,H?pfl, Herbert
, (2019/05/15)
A series of six new Zn (II) compounds, viz., [Zn(HLASA)2(Py)2] (1), [Zn(HLMASA)2(Py)2] (2), [Zn(HLMASA)2(4-MePy)2] (3), [Zn(HLCASA)2(4-MePy)2] (4), [Zn(HLBASA)2(Py)2] (5), [Zn(HLBASA)2(4-MePy)2] (6) and representative Cu (II) and Cd (II) complexes, viz., [Cu(HLASA)2(Py)2(H2O)] (7) and [Cd(HLBASA)2(Py)3] (8) [(HLXASA)??=?para-substituted 5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoate with X?=?H (ASA), Me (MASA), Cl (CASA) or Br (BASA); Py?=?pyridine; 4-MePy?=?4-methylpyridine] have been synthesized and characterized by spectroscopic techniques and single-crystal X-ray diffraction analysis. The structural characterization of the compounds revealed distorted tetrahedral (1–6), square-pyramidal (7) and pentagonal-bipyramidal (8) coordination geometries around the metal atom, in which the aryl-substituted diazosalicylate ligands are coordinated only through the oxygen atoms of carboxylate groups, either in an anisobidentate or isobidentate mode; meanwhile, the 2-hydroxy groups of the monoanionic ligand (HLXASA)? are involved only in intramolecular O-H···O hydrogen bonds with the carboxylate function. In the crystal structures of 1–8, the complex molecules are assembled by π-stacking interactions giving mostly infinite 1D strands. The intermolecular binding in the solid state structures is accomplished by diverse additional non-covalent contacts including C-H···O, C-H···N, C-H···π, C-H···Br, O···Br, Br···π and van der Waals contacts. Although the primary and secondary ligands in the Zn (II) complex series 1–6 carry different substituents at the periphery (X?=?H, Me, Cl, Br for (HLXASA)? and R?=?H, Me for 4-Py-R), five of the crystal structures were isostructural. Additionally, the antimicrobial activity of the pro-ligands H2LXASA and their Zn (II), Cu (II) and Cd (II) compounds were studied in a comparative manner, showing high sensitivity (IZD?≥?20) against Bacillus subtilis.
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.