Logo
User Name

E. Kahrović

Društvene mreže:

Ajla Alijagic, E. Kahrović, Saida Ibragic

This paper describes the combined use of several analytical methods to characterise the painting technology used in two socialist realism portraits of national heroes from World War II that are now housed in the Historical Museum of Bosnia and Herzegovina. Inspection under UV light has shown that there was no previous retouching or overpainting on either painting. Microchemical tests identified the type of canvas. The radiograms indicated whether pigments with lower or higher atomic masses were used and how well the ground was rubbed among the threads of the canvas. A better penetration of the ground into the canvas and layers of oil dye that were applied to both sides of Painting 1 contributed to its better protection against high humidity. TLC revealed the type of ground on both paintings as a classic chalk-glue ground. The high humidity was responsible for the occurrence of metal soaps on Painting 2, which were confirmed by FTIR. The XRF analysis was used to describe the pigment palette, trace the causes of existing damages, and facilitate retouching. The results of this integrated diagnostic approach were used to optimise the conservation and better understand the features and techniques used in the creation of Bosnian socialistic artwork.

A. Zahirović, Irnesa Osmanković, A. Osmanović, A. Višnjevac, Amina Magoda, Selma Hadžalić, E. Kahrović

Two copper(II) complexes of 4-chloro- and 4-dimethylaminobenzaldehyde nicotinic acid hydrazones were prepared and characterized by elemental analysis, mass spectrometry, infrared and electron spectroscopy and conductometry. These rare examples of bis(hydrazonato)copper(II) complexes are neutral complex species with copper(II) center coordinated with two monoanionic bidentate O,N-donor hydrazone ligands coordinated in enol-imine form. The interaction of hydrazone ligands and corresponding copper(II) complexes with CT DNA and BSA was investigated. Copper(II) complexes are slightly effective in binding the DNA than pristine hydrazones. The results indicate groove binding or moderate intercalation which are not significantly affected by the nature of substituent at hydrazone ligands. On contrary, affinities of two copper(II) complexes toward BSA significantly differs and depends on the nature of the substituent, however in absence of thermodynamic data difference in nature of binding forces cannot be excluded. The complex bearing electron-withdrawing 4-chloro substituent has larger affinity toward BSA compared to 4-dimethyamino analogue. These findings were theoretically supported by molecular docking study.

: Complexes of general formula [ Ru(bpy) 2 (L) ]CF 3 SO 3 , where bpy = 2,2′ - bipyridine, and L = Schiff bases derived from salicylaldehyde and amino acids (glycine ( 1a), cysteine (1b), methionine (1c ) and phenylalanine ( 1d )) were synthesized. Characterization based on elemental analysis, Ru content, mass, infrared and electronic spectra confirmed RuN 5 O coordination unlike 1b where coordination occurred via azomethine nitrogen and cysteine sulfur. Cyclic voltammograms, except 1b, showed several quasi- reversible redox pairs in the positive potential range, the first located at about 0.5 V, corresponding to similar heteroleptic Ru(II) bipyridyl complexes. Biological activity was tested by interactions with DNA and BSA. DNA binding constants of order 10 3 M − 1 , suggest groove binding due to bpy ligand and hydrogen bonding of the OH and CO groups from the imine moiety. In vitro BSA protein inhibition assay performed by spectrofluorimetry showed Complex : BSA binding in 1 : 1 ratio with K b of 10 4 M − 1 order. Cytotoxicity studies by MTT assay for 72 h of drug action revealed activity of 1a and 1d against breast cancer MCF- 7 cells with IC 50 values 32 ± 8 and 26 ± 1µM, respectively.

A. Zahirović, S. Roca, E. Kahrović, A. Višnjevac

Abstract The chiral-at-metal, piano-stool ruthenium(II) racemic organometallic [Ru(cymene)(chalconato)(pyridine)]PF6 was prepared by a multistep solution synthesis and its molecular and crystal structure was determined by single crystal X-ray diffraction. The compound crystallizes in a centrosymmetric triclinic P-1 space group with two molecules of opposite chirality within the asymmetric unit. Ruthenium is embedded in an octahedral half-sandwich coordination environment with four different donors, which generates the chirality of the metal centre. The formation of the organometallic was monitored ex-situ by infrared spectroscopy. The pyridine coordination to Ru(II) was particularly analysed to find its characteristic marker bands. The complex was also characterized by elemental analysis and NMR spectroscopy in solution. Its interaction with CT DNA and bovine serum albumin (BSA) was investigated by electron spectroscopy and spectrofluorimetry. The organometallic binds to DNA predominantly by electrostatic forces with low Kb value. On the contrary, its high affinity for BSA was confirmed by strong fluorescence quenching. The synchronous emission spectra revealed that the microenvironment of tryptophan is more affected compared to the environment of tyrosine.

A. Zahirović, S. Roca, A. Višnjevac, E. Kahrović

Abstract Four new organoruthenium(II) compounds of 2’-hydroxychalcones, differing in the position of the chloro substituent at chalcone moiety, were prepared by solution synthesis and characterized by chemical analysis, infrared and electron spectroscopy, mass spectrometry and 1D and 2D NMR spectroscopy, as biomimetic functional models of catechol oxidase. The molecular and crystal structures of three compounds were determined by single crystal X-ray diffraction. The organometallics are neutral species having piano-stool pseudo octahedral geometry with ruthenium(II) coordinated by η6-cymene, bidentate monobasic 2’-hydroxychalcone ligand, and chloride ion. The catecholase activity of new organometallics was investigated by electron spectroscopy in three solvents at three temperatures. The kinetic measurements were done under pseudo first order conditions and vmax, kcat, KM, TON, TOF, and Ea values are determined. Compounds (1) – (4) have solvent-dependent catecholase activity with activity decreasing in order ethanol > methanol ≫ acetonitrile. The highest kcat value and the lowest activation energy were found for the reaction catalyzed by organometallic (4), having a chloro substituent at the B ring of the chalcone ligand in the para position. The kcat values of 104 h−1 and 105 h−1 order at 297 K and 307 K, respectively classify these organometallics among the best artificial functional models of catechol oxidase. The results indicate that the catechol oxidation mediated by organometallics (1) – (4) proceeds via semiquinone radical formation.

E. Kahrović, V. Jakovljevic, A. Zahirović

Studies of materials used for works of art and cultural monuments throughout the history contribute to the comprehensive understanding of particular cultures, their technological achievements and customs over time. Investigations of the authenticity of objects and the interventions they may have endured over time keep an important role for their successful restoration and preservation. A three-layer sample of the colored wall decoration from Ottoman Ćejvan Ćehaja mosque from Mostar, Bosnia and Herzegovina was investigated by FTIR spectroscopy. The plaster was identified as gypsum-lime binder. Inorganic pigments were found in two layers, reddish-brown mixture of Fe2O3 and MnO2 and green pigment recognized as viridian, Cr2O3 ∙ 2H2O. The upper layer of "golden color" is found to be a physically compact piece of gold foil or leaf whose fixation method meets both the Ottoman and "west" mode of binding. The mode of adhesion by animal glue could be the result of decoration immanent to Islamic culture, but also to reconstruction from the late 19th century during the Austro-Hungarian rule in Bosnia.

...
...
...

Pretplatite se na novosti o BH Akademskom Imeniku

Ova stranica koristi kolačiće da bi vam pružila najbolje iskustvo

Saznaj više