Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Valentina Uivarosi x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

A series of new complexes with mixed ligands of the type RuL2(DMSO)mCl3·nH2O ((1) L: norfloxacin (nf), m = 1, n = 1; (2) L: ciprofloxacin (cp), m = 2, n = 2; (3) L: ofloxacin (of), m = 1, n = 1; (4) L: enrofloxacin (enro), m = 0.5, n = 4; DMSO: dimethylsulfoxide) were synthesised and characterised by chemical analysis and IR data. In all complexes both fluoroquinolone derivative and DMSO act as unidentate. The thermal behaviour steps were investigated in synthetic air flow. The thermal transformations are complex processes according to TG and DTG curves including dehydration, quinolone derivative and DMSO degradation respectively. The final product of decomposition is ruthenium (IV) oxide.

Restricted access

Abstract

Two new complexes with formula VOL2·nH2O ((1) L: 4′,5,7-trihydroxyflavone-7-rhamnoglucoside (naringin), n = 8; (2) L: 3′,4′,7-tris[O-(2-hydroxyethyl)]rutin (troxerutin), n = 0) were synthesised and characterised. The IR and UV–Vis spectral data indicate that these flavones act as bidentate chelating ligands and generate VO(II) complexes with a square-pyramidal stereochemistry. The thermal analysis (TG, DTA) elucidated the composition and also the number and nature of the water molecules. The thermal behavior indicates also a strong interaction between oxovanadium (IV) and these oxygen donor ligands.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Mihaela Badea, Rodica Olar, Valentina Uivarosi, Dana Marinescu, Victoria Aldea, Stefania Felicia Barbuceanu, and George Mihai Nitulescu

Abstract

Two new complexes having general formula VOL2·nH2O [(1) L: 5-hydroxyflavone, n = 1; (2) L: chrysin, n = 4] were synthesized and characterized. Based on IR and electronic data we concluded that studied flavones act as bidentate ligands in complexes with metallic ion coordinated in a square-pyramidal stereochemistry. The thermal analysis (TG, DTA) elucidated the composition and also the number and nature of the water molecules. The thermal behavior also indicated strong interactions between oxovanadium (IV) and these oxygen donor ligands.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Mihaela Badea, Rodica Olar, Dana Marinescu, Valentina Uivarosi, Teodor Nicolescu, and Daniela Iacob

Abstract  

A series of new complexes with mixed ligands of the type RuLm(DMSO)nCl3·xH2O ((1) L: oxolinic acid (oxo), m = 1, n = 0, x = 4; (2) L: pipemidic acid (pip), m = 2, n = 1, x = 2; (3) L: enoxacin (enx), m = 2, n = 1, x = 0; (4) L: levofloxacin (levofx), m = 2, n = 2, x = 8; DMSO: dimethylsulfoxide) were synthesized and characterized by chemical analysis, IR and electronic data. Except oxolinic acid that behaves as bidentate, the other ligands (quinolone derivatives and DMSO) act as unidentate. Electronic spectra are in accordance with an octahedral stereochemistry. The thermal analysis (TG, DTA) in synthetic air flow elucidated the composition and also the number and nature of both water and DMSO molecules. The TG curves show 3–5 well-separated thermal steps. The first corresponds to the water and/or DMSO loss at lower temperatures followed either by quinolone thermal decomposition or pyrolisys at higher temperatures. The final product is ruthenium(IV) oxide.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Valentina Uivarosi, Mihaela Badea, Rodica Olar, Dana Marinescu, Teodor Octavian Nicolescu, and George Mihai Nitulescu

Abstract

Three new complexes with ligands belong to the fluoroquinolone class having the general formula [RuL2Cl2]Cl nH2O ((1) L: norfloxacin (nf), n = 4; (2) L: ciprofloxacin (cp), n = 3; (3) L: enrofloxacin (enro), n = 5) were synthesized and characterized by chemical analysis UV–Vis and IR spectroscopy. In all complexes fluoroquinolone derivative acts as bidentate chelate ligand. The thermal behavior steps were investigated in synthetic air flow. The thermal transformations are complex processes according to TG and DTG curves including dehydration, quinolone derivative degradation, as well as RuCl3 conversion in RuO2.

Restricted access

A series of new complexes of the type VO(OH)L·nH2O ((1) L: fisetin, n = 3; (2) L: quercetin, n = 2; (3) L: morin, n = 4) were synthesised and characterised by analytical as well as IR and electronic data. The modification evidenced in IR spectra was correlated with the presence of flavonoid as bidentate in all complexes. The electronic reflectance spectra showed the dd transition characteristic for the square-pyramidal stereochemistry of vanadium (IV) ion. The thermal analysis (TG, DTA) in synthetic air flow elucidated the composition and also the number and nature of the water molecules. The TG curves show three well-separated thermal events. The first corresponds to the water loss at lower temperatures, which is followed by flavonoid derivative decomposition and pyrolysis at higher temperatures. The final product is vanadium (V) oxide.

Restricted access