Thermal behaviour of Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and Pd(II) complexes with isatin-beta-thiosemicarbazone

The isatin-beta-thiosemicarbazone (ITC) complexes of Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and Pd(II) were prepared and characterized by elemental analysis, as well as molar conductivity, magnetic susceptibility, FTIR, UV-Vis and H-1 NMR spectroscopic methods. The complexes were also studied for its thermal stability. They all behaviour as anhydrous complexes and its thermolysis passes through the stages of deamination (517-547 K) and complete thermal decomposition (619-735 K).32nd Workshop on Heterogeneous Equilibria between Phases (JEEP 2006), Mar 30-31, 2006, Univ Rouen, Rouen, Franc

Antimicrobial activity of some isatin-3-thiosemicarbazone complexes

Isatin-3-thiosemicarbazone complexes with Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and Pd(II) were synthesized and evaluated for their antimicrobial activity against 7 pathogenic bacteria and 4 fungi. The complexes have an enhanced activity compared to the ligand due to transition metal involved in coordination. The anti-amoebic activity in vitro was evaluated against the HM1:IMSS strain of Entamoeba histolytica and the results were compared with the standard drug, metronidazole. The preliminary test results showed that the complexes had better anti-amoebic activity than their respective ligands. Moreover, the complexes showed better inhibition of the test organism

The influence of Schiff base inclusion complexes with β-cyclodextrine on antibiotic production by Streptomyces hygroscopicus CH-7

A media consisting of isatin-Schiff bases and its inclusion complexes with beta-cyclodextrine was developed to maximize the production of antibiotics Hexaene H-85 and azalomycine B by Streptomyces hygroscopicus CH-7. The media With (-cyclodextrine inclusion complex of isatin-3-thiosemicarbazone resulted in the maximum antibiotics concentration of 493 ìg/cm3 for Hexaene H-85 and 191 ìg/cm3 for azalomycine B. The production of hexaene H-85 and azalomycine is higher when (-cyclodextrine complex is added as a nitrogen source, comparing to pure isatin-Schiff base. The maximum concentration of hexaene H-85 in medium with inclusion complex of isatin-Schiff base is 1.4-2.3 times higher than the basal medium. The maximum production of azalomycine is 2.1-3.4 times higher in media with inclusion complex of Schiff base. During the fermentation process, the nutrient media with (-cyclodextrine inclusion complexes with isatin-Schiff bases affect the strain morphology, since it is in the form of compact pellets, which are formed from short and long, branched filaments.Streptomyces hygroscopicus je soj poznat po produkciji različitih vrsta antibiotika i komercijalno važnih sekundarnih metabolita. Formiranje metabolita je rezultat mikrobioloških procesa u toku fermentacije i zavisi od nivoa biomase mikroorganizma, morfološkog profila kulture, kao i od ekoloških uslova. U cilju povećanja prinosa antibiotika, osnovna hranljiva podloga je redefinisana izmenom izvora azota, tako što su umesto sojinog brašna (10 g/dm3) dodati kompleksi Šifovih baza sa (-ciklodekstrinom (10 g/dm3). Dodatak kompleksa Šifovih baza sa bciklodekstrinom rezultirao je znatno povećanje koncentracije oba antibiotika. Maksimalna koncentracija heksaena H-85 je ostvarena na podlozi sa kompleksom izatin-3-tiosemikarbazona sa (-ciklodekstrinom i iznosila je 493 ìg/cm3, dok je za azalomicin B iznosila 191 ìg/cm3. Povećanje maksimalnih koncentracija antibiotika na podlogama sa kompleksima Schiff-ovih baza je iznosilo 1,4-2,3 puta za heksaen H-85, odnosno 2,1-3,4 puta za azalomicin B, u odnosu na osnovnu podlogu. U toku procesa fermentacije na hranljivim podlogama sa kompleksima Šifovih baza sa (-ciklodekstrinom, soj raste u obliku kompaktnih peleta, koji se formiraju od kratkih i dugih, razgranatih filamenata

Spectrophotometric study of Co(II), Ni(II), Cu(II), Zn(II), Pd(II) and Hg(II) complexes with isatin- β-thiosemicarbazone

The composition and stability of the complexes of isatin-b-thiosemicarba­zone with Co(II), Ni(II), Cu(II), Zn(II), Pd(II) and Hg(II) have been investigated us­ing spectrophotometric method at 30 °C and constant ionic strength of 0.1 mol dm-3 (KNO3) in 70 % ethanol. Experimental results indicate the formation of MeL and MeL2 complexes for Ni(II) and Co(II), and MeL for Cu(II), Zn(II), Pd(II) and Hg(II) complexes, whose stability constants, bn, have been calculated using a com­puteri­zed iterative method of successive approximation

Nanocomposites based on silica-reinforced ethylene-propylene-diene-monomer/acrylonitrile-butadiene rubber blends

Rheometric characteristics, curing kinetics, mechanical properties before and after thermal aging and morphology of nanocomposites based on various network precursors (i.e., acrylonitrile-butadiene rubber (NBR), ethylene-propilene-diene monomer (EPDM) and its blend (NBR/EPDM) reinforced of nanosilica) is presented here. The ratios of EPDM and NBR as binary blend system vary significantly. The rheometric characteristics and curing kinetics of nanocomposites were determined using a rheometer with an oscillating disk, in which the network formation process was registered by the varying torque durations. The mechanical properties of the elastomeric composites were determined before and after thermal aging using an air-circulating oven. The specific interactions between the rubber and filler were characterized by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was employed to study the surface morphology of fractured rubber. The obtained results demonstrated a correlation between the calculated activation energies of cross linking (Eac) and reversion (Ear) and mechanical properties, which can be seen in sample EPDM/NBR = 20/80. For this blend, maximum tensile strength values and synergism were observed. Additionally, this blend exhibited a relatively co-continuous morphology, which was investigated by SEM. The differential scanning calorimetry (DSC) curves reported that the silica-reinforced EPDM/NBR rubber blends were immiscible. FIR studies showed a strong interaction between the polymer matrix and filler, which was reflected in the peak shifts at 1441.9 and 1462.5 cm(-1) to higher wave numbers. (C) 2011 Elsevier Ltd. All rights reserved