D Aleksandar Marinkovic

Synthesis, antioxidant and antimicrobial activity of carbohydrazones

Fourteen mono - and bis -carbohydrazone ligands have been synthesized and characterized. Antioxidant activity of the substances was investigated together with possible ( E ) / ( Z ) isomerization, and explained on the most active antioxidant compound a4 in various dimethylsulphoxide–water mixtures. The addition of water to the system was involved in the formation of hydrated molecules which was confirmed in NMR after the addition of D 2 O. The ligands were tested in vitro against Gram-positive and Gram-negative bacteria and fungis, and their activity was discussed in relation to the structure of investigated carbohydrazone.

Solvatochromism of isatin based Schiff bases: LSER and LFER study

The derivatives of isatin have already been reported to show a variety of biological activities. However, there has been no report on solvatochromic effect of isatin derivatives so far, and that could be of interest to study and relate to their electronic structure, as a part of the characterisation of these compounds. Linear solvation energy relationships (LSER) were used to analyze solvent influence on the UV absorption maxima shifts of investigated isatin derivatives, i.e . isatin based Schiff bases, by using Kamlet–Taft model. Linear free energy relationships (LFER) were applied to the substituent-induced NMR chemical shifts ( SCS ) using SSP (single substituent parameter). The obtained correlations together with theoretical calculations gave insight into the influence of the molecular conformation on the transmission of substituent effects, as well as on solute/solvent interactions. The molecular electrostatic potential (MEP) surface map was plotted over the optimized geometry of the molecules in order to visualize electron density distribution and explain origin of solvent/solute interactions.

Removal of heavy metals from water using multistage functionalized multiwall carbon nanotubes

The multistage synthesis of the multi-wall carbon nanotubes (MWCNT) modified with polyamidoamine dendrimers, A1/ and A2/MWCNT, capable of cation removal, is presented in this work, as well as novel adsxadorbents based on these precursor materials and modified with goethite nano-deposit, α -FeOOH, A1/ and A2/MWCNT– α -FeO(OH) adsorbents used for As(V) removal. In a batch test, the influence of pH, contact time, initial ion concentration and temxadperature on adsorption efficiency were studied. Adsorption data modelling by the Langmuir isotherm, revealed good adsorption capacities (in mg g -1 ) of 18.8 for As(V) and 60.1 and 44.2 for Pb 2+ and Cd 2+ on A2/MWCNT, respectively. Also, 27.6 and 29.8 mg g -1 of As(V) on A1/ and A2/MWCNT– α -FeO(OH), respectively, were removed. Thermodynamic parameters showed that the adsxadorpxadtion is spontanexadous and endothermic processes. Results of the study of infxadluences of competxaditive ions: bicarbonate, sulfate, phosphate, silicate, chromate, fluoride and natxadural organic matter (NOM), i.e. , humic acid (HA), showed the highest effect of phosphate on the decrease of arsenate adsorption. Time-depxadendent adsorption was best described by pseudo-second-order kinetic model and Weber–Morris model which predicted intra-particle diffusion as a rate-conxadtrolling step. Also, activation energy ( E a / kJxa0mol -1 ): 8.85 for Cd 2+ , 9.25 for Pb 2+ and 7.98 for As(V), were obtained from kinetic data.

Synthesis and characterization of phencyclidine and his derivatives

Phencyclidine (PCP) or 1-phenyl-cyclohexylpiperidine is the best-known representative drug from the compound class of arylcyclohexylamines. On a pharmacological activities basis, it belongs to the family of drugs known as dissociative anesthetics. In recent years, great attention has been paid to the investigation of substances that have been abused, including PCP. PCP is a synthetic drug with stimulating and hallucinogenic effects (street name angel dust), and it is included in the Schedule Substances List in Serbia and worldwide. In the beginning, PCP has been sold in pharmacies as a local anesthetic, but very quickly it was withdrawn from sale because of unwanted effects on consumer health causing psychoactive addiction. Taking into account that great attention is being given nowadays to substances that are subject of abuse, biological and pharmacological effects of PCP and its derivative, which depend on their structure and methods for synthesis, is described in this paper. It is shown that PCP is antagonist of N-methyl-D-aspartate (NMDA) and that it causes antiglutamatergic hallucinations, unlike BTCP whose agonist is an NMDA receptor and is obtained by modifying the structure of PCP. This paper presents a PCP metabolism and provides an overview of the methods for their identification and quantification in biological samples. Immunological tests of PCP in biological samples can provide a quick but wrong result because of the possible interference with the other substances of abuse as opposed to instrumental methods. Based on the presented method and the results it was concluded that the method of choice for the examinations of biological samples for the presence of PCP is gas chromatography in combination with mass spectroscopy.