Biological Activity of Some Cobalt(II) and Molybdenum(VI) Complexes: in vitro Cytotoxicity

Cytotoxicity and cell growth inhibition studies were performed for five distinct cobalt(ll) [Co2(acac)tpmc](ClO4)3, [Co2(dibzac)tpmc](ClO4)3, [Co2(hfac)tpmc](CIO4)2, [Co2(tmhd)tpmc](CIO4)3 and [Co2(ox)tpmc](CIO4)2.3H20 and five molybdenum(Vl) complexes, [MoO2(pipdtc)2], [MoO2(morphdtc)], [MoO2(timdtc)2], [MoO2(pzdtc)2] and [MoO2(N-Mepzdtc)2]. The former were tested in two leukemia cell lines: chronic myelogenic leukemia (K562) and human promyelocytic cell line (U937). They showed to have relatively high toxicity in K562 cells and a relatively low cytotoxicity in U937 cells, as assessed by both MTT and Trypan Blue assays. The five molybdenum complexes were tested in human promyelotic U937 cell line and they showed to have high toxicity

Komparativno elektrohemijsko ispitivanje nekih kobalt(III)i kobalt(II) kompleksa sa azamakrocikličnim i β-diketonato ligandima

The electrochemical properties of eight mixed-ligand cobalt(III) and co balt(II) complexes of the general formulas [CoIII(Rac)cyclam (ClO4)2 (1)–(4) and [Co2II(Rac)tpmc](ClO4)3 (5)–(8) were studied. The substances were investigated in aqueous NaClO4 solution and non-aqueous LiClO4/CH3CN solution by cyclic voltam metry at a glassy carbon electrode. In aqueous solution, cyclam and Rac ligands being soluble in water undergo anodic oxidation. Coordination to Co(III) in complexes 1–4, stabilizes these ligands but reversible peaks in catohodic region indicate the redox reaction CoIII/CoII ion. In the case of the binuclear Co(II) complexes 5–8, peaks recorded on the CVs represent oxidation of the bridged Rac ligand. The complexes examined influence the cathodic reaction of hydrogen evolution in aqueous solutions by shifting its potential to more negative values and its current is increased. In non-aqueous solution the CVs of the ligands show irreversible anodic peaks for cyclam, tpmc and for the Rac ligands soluble in acetonitrile. The absence of any peaks in the case of the investigated complexes 1–4 indicates that coordination to Co(III) stabilizes both the cyclam and Rac ligands. Cyclic voltammograms of the complexes 5–8 show oxidation processes of the Rac ligand and Co(II) ions but the absence of a highly anodic peak of the coordinated macrocycle tpmc shows its stabilization. Contrary to in aqueous solution, the redox reaction Co(III)/Co(II) does not occur in acetonitrate indicating a higher stability of the complexes 1–4 in this media in comparison with the binuclear cobalt(II)-tpmc complexes 5–8.Cikličnom voltametrijom ispitano je osam kompleksa kobalta(III) i kobalta(II)sa mešovitim ligandima, opšte formule CoIII(Rac)cyclam (ClO4)2 (1)–(4) i CoII(Rac)tpmc (ClO4)3 (5)–(8), u vodenoj (NaClO4) i nevodenoj (LiClO4/CH3CN) sredini. U vodenoj sredini cyclam i Rac ligandi podležu anodnoj oksidaciji. Koordinacija sa Co(III) u komp- leksima (1)–(4) stabilizuje ove ligande ali dolazi do redoks reakcije Co(III)/Co(II).U slučaju binukelarnih Co(II) kompleksa (5)–(8) dolazi do oksidacije Rac liganada. Ispitivani kompleksi u vodenom rastvoru utiču na reakciju izdvajanja vodonika katodno pomerajući potencijal i povećavajući struju. U nevodenim rastvorima anodno se oksiduju oba makrociklična (cyclam i tpmc) i Rac ligandi rastvorni u acetonitrilu. Međutim, u ovim rastvorima Co(III) kompleksa ne dolazi do elektrohemijskih reakcija što znači ne samo da i ovde koordinacija sa kobaltom stabilizuje ligande već nema ni redoks reakcije za kobalt. Sa druge strane, u Co(II) komplesima stabilizovan je tpmc ali se oksiduju Rac ligandi i Co(II) pa su tako u nevodenim rastvorima kompleksi Co(III) stabiliniji od binukelarnih Co(II)-tpmc kompleksa

Mehanizam oksidacije legura Fe-C-Si-Al-Zr

Mechanism of the oxidation of the thermal-resistant Fe-C-Si-Al-Zr alloys was investigated at high temperatures. For the analysis three series samples: L1, L2 and L3, had been annealed at 1100 °C, were cast. After annealing the samples were investigated on the oxide thickness increase. They were observed and analysed by optical and electron microscopes. In case of the small zirconium content in the L1 sample, the graphite lamellae and only a significant amount of zirconium carbide in the ferrite matrix have been observed. At higher zirconium content (the L2 and L3 samples) graphite lamellae and particles of ZrC have been observed. During annealing an oxidation of graphite and ZrC took place. The oxidation of ZrC into ZrO2 is direct and progressive. Evolving CO gas formed the pores around ZrO2. Under sufficient amount of the dissolved oxygen the oxidation of aluminium was taking place too. Al2O3 was precipitating in the CO-ferrite interface filling up the formed pores. Finally the interaction between ZrO2 and Al2O3 were taking place and formation the compound of ZrO2·Al2O3 retarded further oxidation.Ispitivao se mehanizam oksidacije termički otpornih legura Fe-C-Si-Al-Zr na visokim temperaturama. Za analizu su izlivena tri serijska uzorka L1, L2 i L3, i žarena na 1100 °C. Nakon žarenja uzoraka ispitivana je debljina oksidnog sloja. Promatrani su i analizirani optičkim i elektronskim mikroskopom. Kad je količina cirkonija bila mala u uzorku L1 uočene su grafitne lamele i čestice ZrC. Tijekom žarenja došlo je do oksidacije grafita i ZrC. Oksidacija ZrC u ZrO2 je vanjska i progresivna. Razvija se plin CO, koji oko ZrO2 formira pore. Kad je količina rastopljenog kisika postala dovoljno velika došlo je također do oksidacije aluminija. Al2O3 se istaložio u CO-feritnom međuprostoru i popunio postojeće pore. Konačno je došlo do interakcije između ZrO2 i Al2O3 te se stvorio spoj ZrO2·Al2O3 koji je usporio daljnju oksidaciju

Electrochemical examination of mixed-ligand cobalt(III) complexes with tetraazamacrocyclic ligand and heterocyclic dithiocarbamates

Electrochemical stability of eight complexes of the general formula [co 111 Rdtc(1-8)cyclam](ClO 4 ) 2 , where cyclam=1,4,8,11-tetraazacyclotetradecane and Rdtc - (1-8)=4-morpholine (Morphdtc), 4-thiomorpholine (Timdtc), 4-piperazine (Pzdtc), N-methyl piperazine (N-Mepzdtc), piperidine (Pipdtc), 2-, 3- or 4-methylpiperidine (2-, 3- or 4-Mepipdtc) dithiocarbamates, respectively, were studied. The substances were examined in aqueous NaClO 4 solution and nonaqueous LiClO 4 in CH 3 CN solution by cyclic voltammetry. In aqueous solution, macrocyclic ligand cyclam is characterized by the anodic peak at 0.95 V. The Rdtc - ligands have two anodic peaks, one in the region 0.25-0.30 V and the other in the 0.78-0.95 V region. Absence of these anodic peaks in the case of the complexes indicates that coordination to cobalt(III) stabilizes both cyclam and Rdtc - ligands, but reversible peaks in the range -0.68 to -0.78 V support the Co(III) redox reaction. In nonaqueous solutions cyclam has one anodic peak at 1.75 V. The ligands with heteroatom in the ring (Morphdtc, Timdtc, Pzdtc, N-Mepzdtc) have two anodic peaks, while the other four ligands (Pipdtc, 2-, 3- and 4-Mepipdtc) have only one anodic peak. In nonaqueous solution again, coordination to Co(III) ion stabilizes the Rdtc - ligands and contrary to aqueous solution no Co(III) redox reaction occurs, indicating a greater stability of the complexes in this media. Finally, the electrochemical results are compared with spectroscopic data obtained previously

Actes du 12e Colloque de l'ARC

Eight mixed-ligand cobalt(III) complexes with the macrocyclic amine 1,4,8,11-tetraazacyclotetradecane (cyclam) and a heterocyclic dithiocarbamate (Rdtc-)i.e., morpholine-(Morphdtc), thiomorpholine- (Timdtc), piperazine-(Pzdtc), N-methylpiperazine-(Mepzdtc), piperidine- (Pipdtc), 2-, 3- or 4-methylpiperidine-(2-, 3- and 4-Mepipdtc) carbodithionato-S,S ions, of the general formula [Co(cyclam)Rdtc](ClO4)2, were investigated in deoxygenated 0.1 MHClO4 solutions. Cyclic voltammetry data at a glassy carbon (GC) electrode demonstrate a redox reaction of cobalt(III) from the complexes at potentials strongly influenced by the presence of different heterocyclic Rdtc- ligands. In this respect, the complexes were separated into two groups: the first, with a heteroatom O, S or N in the heterocyclic ring, and the second, with a methyl group on the piperidine ring of the Rdtc- ligand. Anodic polarization of an Fe electrode in the presence of the complexes shows their influence not only on the dissolution of iron but also on the hydrogen evolution reactions and on this basis complexes the complexes could be divided into the same two groups. It was found that the weaker the inhibiting effect of the free heterocyclic amines is, the significantly higher is the efficiency of the corresponding complexes.Osam mešovito-ligandnih kompleksa kobalta(III) sa makrocikličnim aminom 1,4,8,11-tetraazaciklotetradekanom (cyclam) i heterocikličnim ditiokarbamatima (Rdtc-) t.j., morfolin-(Morphdtc), tiomorfolin-(Timdtc), piperazin-(Pzdtc), N-metilpiperazin-(Mepzdtc), piperidin-(Pipdtc), 2-, 3- ili 4-metilpiperidin- (2-, 3- i 4-Mepipdtc) karboditionato-S,S jonima, opšte formule [Co(cyclam)Rdtc)](ClO4)2 , ispitano je u 0,1 M HClO4 rastvoru na elektrodi od staklastog ugljenika i gvožđa. Ciklična voltametrija na elektrodi od staklastog ugljenika pokazala je da dolazi do redoks reakcije kobalt(III) jona iz kompleksa. Različiti heterociklični Rdtc- ligandi utiču na vrednost potencijala ove redoks reakcije. Na osnovu ovih vrednosti kompleksi se mogu podeliti u dve grupe: jednu sa heteroatomom u heterocikličnom prstenu i drugu sa metil-grupom na piperidinskom prstenu Rdtc- liganda. Anodna polarizacija gvožđa u prisustvu kompleksa pokazala je njihov uticaj ne samo na reakciju rastvaranja metala već i na reakciju izdvajanja vodonika. Rezultati su pokazali da što je slabiji inhibitorski efekat heterocikličnog amina to je veći uticaj odgovarajućeg kompleksa

The inhibiting effect of cobalt(III)-cyclam complexes with substituted β-diketones on iron corrosion in perchlorate solution

The inhibiting effect of cobalt(III) complexes with macrocyclic ligand cyclam (1,4,8,11-tetraazacyclotetradecane) and β-diketonato ligands have been investigated on iron corrosion in 0.1 M HClO 4 by potentiodynamic, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) measurements. Analysis of the polarization curves and impedance spectra, by adding complex compounds to the acid solution and comparing with inhibitor-free solution, show corrosion current decrease and charge transfer resistance increase, respectively. Impedance data are fitted with equivalent circuit models. The stability of the adsorbed film was followed by LPR. Scanning electron microscopy (SEM) was used to screen physical changes of the reacted surfaces both treated and untreated. The differences in inhibitor efficiencies depend on the substituent group of the coordinated β-diketone ligand. Structural and electronic properties of this group of compounds in relation to inhibitor efficiency were analyzed by using the molecular modeling structures and correlated with previously reported spectroscopy data

Using Radio Irregularity for Increasing Residential Energy Awareness

Radio irregularity phenomenon is often considered as a shortcoming of wireless networks. In this paper, the method of using radio irregularity as an efficient human presence detection sensor in smart homes is presented. The method is mainly based on monitoring variations of the received signal strength indicator (RSSI) within the messages used for the communication between wireless smart power outlets. The radio signals used for the inter-outlets communication can be absorbed, diffracted or reflected by objects in their propagation paths. When a human enters the existing radio communication field, the variation of the signal strength at the receiver is even more expressed. Based on the detected changes and compared to the initial thresholds set during the initialization phase, the system detects human presence. The proposed solution increases user awareness and automates the power control in households, with the primary goal to contribute in residential energy savings. Compared to conventional sensor networks, this approach preserves the sensorial intelligence, simplicity and low installation costs, without the need for additional sensors integration

Canine babesiosis treatment with three different medicines

Canine babesiosis is a relatively frequent disease in Croatia. Elevated body temperature, anemia and haemoglobinuria are the most common signs. Diagnosis is rapidly obtained by employing blood smears, as B. canis is present in the red blood cells of affected dogs. Treatment is favourable and without consequences. Blood work was performed initialy, prior to treatment, and on the 1st and the 7th day following treatment. Following history and examination of the dogs blood and urine samples were taken. After confirmation of B. canis in the red blood cells, alltogether 226 dogs were tretated. Out of them 80 were tretaed with Berenil® (diminazen aceturate, Hoechst), 72 were tretated with Imizol® (imidocarb dipropionate, Schering-Plough-Animal-Health) and 74 with Oxopirvedin® (fenamidine dizetionate, Merial). Clinical findings, haematological analysis and urine analysis are given and statistically assesed. After tretment with Berenil®, symptoms of babesiosis regressed within 24 hours. Health improved more slowly in the group treated with Oxopirvedin® in comparioson with the group treated with Berenil®. Contrary to the above, Imizol® displayed the slowest regression of the disease and reinfestation with B. canis within 30 days was not noted. That is not the case if treatment was provided by Berenil® and Oxopirvedin®. In all 226 cases of canine babesiosis side effects were not noted, except topically inflammed tissue at the site of subcutaneous application