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The condensation product of 7-acetyl-6-azaindole and Girard’s T reagent ((E)-2-(2-(1-(1H-pyrrolo[2,3-c]pyridin-7-yl)ethylidene)hydrazineyl)-N,N,N-trimethyl-2-oxoethan-1-aminium, HL ligand) was used as a ligand in the reaction with Cu(BF4)2·6H2O and NaN3. The reaction led to the formation of a binuclear Cu(II) complex containing two end-to-end (di-m-1,3-N3) azide bridges, as well as two NNO-donor hydrazone ligands, forming an axially elongated square pyramidal geometry around each Cu(II) center. This end-to-end (di-m-1,3-N3) azide bridge binding mode has not yet been reported, in Cu(II) complexes containing the NNO-donor hydrazone ligands, which makes the structure of the complex even more interesting for further studies. The com­plex was characterized by elemental analysis, IR spectroscopy and X-ray crys­tal­lography, and it was found that it crystallizes in the triclinic space group P–1 with the asymmetric unit comprising one Cu(II) centre, zwitterionic ligand L, one azide (N3-) ligand and BF4- counter anion. Examination of antimicrobial activity of the complex shows higher antifungal and antibacterial activity towards tested Gram-positive bacteria in comparison to the hydrazone ligand, with the antifungal activity of the complex even being comparable to the act­ivity of amphotericin B.

Fe(III) and Mn(II) complexes with condensation product of thiosemicarbazide and 2-acetylthiazole (HL1, (E)-2-(1-(thiazol-2-yl)ethylidene)hydrazine-1-carbothioamide) have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. In both complexes, the thiosemicarbazone ligand is coordinated in deprotonated form through the NNS donor set of atoms. However, while Fe(III) complex is in the doublet ground state with distorted octahedral geometry, the coordination environment around Mn(II) is distorted trigonal-prismatic, and the sextet state is found to be the ground state. DFT calculations were performed to rationalize spin state preferences, and continuous shape measure describes the deviation from ideal six-coordinated polyhedral geometries in the ground and excited states. Antimicrobial activity (against a panel of Gram-negative and Gram-positive bacteria, two yeast, and one fungal strain), brine shrimp assay, and DPPH radical scavenging activity of both complexes were evaluated, and these results relate to the electronic structure of the complexes.

Two new Zn(II) complexes bearing tridentate hydrazone-based ligands with NNO or NNS donor atoms were synthesised and characterised by elemental analysis, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies, and single crystal X-ray diffraction methods. These complexes, together with four previously synthesised analogues, having hydrazone ligands with a NNO donor set of atoms, were successfully employed as catalysts in the ketone-amine-alkyne (KA2) coupling reaction, furnishing tetrasubstituted propargylamines, compounds with unique applications in organic chemistry. DFT calculations at the CAM-B3LYP/TZP level of theory were performed to elucidate the electronic structure of the investigated Zn(II) complexes, excellently correlating the structure of the complexes to their catalytic reactivity.

In this paper, we report the synthesis, characterization, and X-ray structure analysis of one octahedral Ni(II) complex, [Ni(HL1 )2](BF4)2*H2O, formed by coordination of two ligands with NNS donor atom sets (HL1 ligand, (E)-2-(1-(thiazol-2-yl)ethylidene)hydrazine-1-carbothioamide), and Ni(III) complex, [Ni(L2 )(N3)3], formed by coordination of one hydrazone ligand coordinated through NNO donor set and three azide anions (HL2Cl ligand, (E)−1-(2-oxo-2-(2-(1-(pyridin-2- yl)ethylidene)hydrazinyl)ethyl)pyridin-1-ium chloride), complemented by DFT calculations. To the best of our knowledge this is the first Ni(III) complex obtained under ambient conditions.

In this paper, the previously synthesized Cu(II) complex ([CuL1(N3) (CH3OH)]BF4) with N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride, has been characterized and its biological activity has been studied in detail. The Cu(II) complex consists of ligand coordinated in a deprotonated, formally neutral zwitter-ionic form, via NNO atoms, one azido ligand and one methanol molecule. The Cu(II) complex was selected due to results of the cytotoxic activity, the brine shrimp test and DPPH radical scavenging activity, which were previously performed. The effects of Cu(II) complex on cell cycle phase distribution of cervical adenocarcinoma HeLa cells were investigated in order to examine the mechanisms of its anticancer activity. The measurement of intracellular ROS levels in HeLa and HaCaT cell lines were evaluated in order to explore their possible generation and the role in cytotoxic activity. The possible anti-invasive and anti-angiogenic properties of Cu(II) complex were evaluated. DNA binding experiments, including fluorescence displacement study and DNA cleavage experiments, were performed in order to obtain information on the type of DNA-metal complex interactions. © 2022 Serbian Chemical Society. All rights reserved.

Previously, the cytotoxic actions of five Pd(II) complexes with bidentate N-heteroaromatic chelators (complexes 1–5) on a palette of several cancer cell lines were investigated. However, the results of the cytotoxic activity did not correlate with the hydrophobic character of the complexes. To gain further insight into the structure–activity relationship, essential for the design of novel potential drugs, other factors, such as non-specific interactions with cellular proteins, have to be taken into account. To explore the potential non-specific influence of the complexes on protein structures, ovalbumin (OVA) was chosen as a model system to mimic cellular non-specific crowding environments with high protein concentrations. A Fourier-transform infrared spectroscopy study implied that the binding of 3 and 4 led to only moderate alternations in the secondary structures of the protein, without the possibility to penetrate into hydrophobic core of the protein and disruption of protein native fold. Contrary, the effect of complex 5 on OVA secondary structures was concentration-dependent. While the lower concentration of complex 5 had no effect on OVA structure, a doubled concentration of complex 5 led to complete disruption of the content native-like secondary structures. The concentration-dependent effect of complex 5 on the changes in secondary structures and considerable increase in the exposure of OVA hydrophobic surfaces to water may be related to a potential crosslinking that leads to OVA aggregation.

In this paper, the previously synthesized Cu(II) complex ([CuL1(N3) (CH3OH)]BF4) with N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride, has been characterized and its biological activity has been studied in detail. The Cu(II) complex consists of ligand coordinated in a deprotonated, formally neutral zwitter-ionic form, via NNO atoms, one azido ligand and one methanol molecule. The Cu(II) complex was selected due to results of the cytotoxic activity, the brine shrimp test and DPPH radical scavenging activity, which were previously performed. The effects of Cu(II) complex on cell cycle phase distribution of cervical adenocarcinoma HeLa cells were investigated in order to examine the mechanisms of its anticancer activity. The measurement of intracellular ROS levels in HeLa and HaCaT cell lines were evaluated in order to explore their possible generation and the role in cytotoxic activity. The possible anti-invasive and anti-angiogenic properties of Cu(II) complex were evaluated. DNA binding experiments, including fluorescence displacement study and DNA cleavage experiments, were performed in order to obtain information on the type of DNA-metal complex interactions. © 2022 Serbian Chemical Society. All rights reserved.

In this work synthesis, characterization and crystal structures of 1, Zn(II) complex ([ZnL1(NCS)2]), with (E)-1-(2-oxo-2-(2-(quinolin-2-ylmethylene)hydrazinyl)ethyl)pyridin-1-ium chloride (HL1Cl) and 2, Bi(III) complex ([BiHL2Cl4] × 1/2CH3OH), with (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL2Cl), have been reported. Zn(II) complex possesses a distorted trigonal bipyramidal geometry while surroundings around Bi(III) ion are extended pentagonal bipyramidal. Antimicrobial activity, brine shrimp assay and DPPH radical scavenging activity of both complexes, including previously synthesized complexes with HL2Cl ligand (Zn(II) and Ni(II)) and complexes with (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL3Cl) (Zn(II), Cu(II), Cd(II), Co(II), Fe(III), Ni(II)), were evaluated. For the most active complexes, cytotoxic activity against five malignant cancer cell lines (HeLa, A375, MCF7, PC-3 and A549) and normal cell line HaCaT, as well as generation of reactive oxygen species (ROS), was tested.

In this work synthesis, characterization and crystal structures of 1, Zn(II) complex ([ZnL1(NCS)2]), with (E)-1-(2-oxo-2-(2-(quinolin-2-ylmethylene)hydrazinyl)ethyl)pyridin-1-ium chloride (HL1Cl) and 2, Bi(III) complex ([BiHL2Cl4] × 1/2CH3OH), with (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL2Cl), have been reported. Zn(II) complex possesses a distorted trigonal bipyramidal geometry while surroundings around Bi(III) ion are extended pentagonal bipyramidal. Antimicrobial activity, brine shrimp assay and DPPH radical scavenging activity of both complexes, including previously synthesized complexes with HL2Cl ligand (Zn(II) and Ni(II)) and complexes with (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL3Cl) (Zn(II), Cu(II), Cd(II), Co(II), Fe(III), Ni(II)), were evaluated. For the most active complexes, cytotoxic activity against five malignant cancer cell lines (HeLa, A375, MCF7, PC-3 and A549) and normal cell line HaCaT, as well as generation of reactive oxygen species (ROS), was tested.

Two square-planar complexes, [PtLCl] (1) and [PdLCl] (2), were synthesized with quinoline-2-carboxaldehyde thiosemicarbazone ligand (HL), and characterized by IR and NMR spectroscopy and single crystal X-ray diffraction analysis. In both complexes, L- is coordinated tridentately via the same donor atom set, while the fourth coordination site is occupied by a chloride ion. However, the complexes are not isostructural due to different types of non-covalent intermolecular interactions. These interactions were analyzed using Hirshfeld surfaces and two-dimensional fingerprint plots.

Two binuclear double end-on azido bridged Ni(II) complexes, [Ni2L2(μ-1,1-N3)2(N3)2]⋅2H2O (1a), and [Ni2L2(μ-1,1-N3)2(N3)2]⋅4H2O (1b) having the same inner sphere, where L=((E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium, were synthesized from the same solution and characterized by single-crystal X-ray diffraction methods. Variable‐temperature magnetic susceptibility measurements showed intra-dimer ferromagnetic coupling between Ni(II) ions. The ferromagnetic coupling is supported by the broken-symmetry DFT calculations, with the level of theory chosen based on a benchmark study on 19 additional structurally related binuclear Ni(II) complexes. The role of water molecules in crystals of 1a and 1b is explained by DFT based energy decomposition analysis.

In this article, synthesis, spectral and X-ray structure characterization, antimicrobial activity and Brine shrimp test of two new Cu(II) complexes with a salicylaldehyde derivative have been reported. Complexes [Cu(L)(bipy)]BF4·0.5H2O and [Cu2(L)2(phen)2](BF4)2 were obtained in the reaction of Cu(BF4)2·6H2O, deprotonated 4-(diethylamino)−2-hydroxybenzaldehyde ligand (L) and α-diimine (2,2’-bipyridine or 1,10-phenanthroline). The complex with bipyridine is mononuclear, containing one L and one bipyridine ligand in a distorted square-planar cation with a BF4 − anion and lattice water molecule, whereas the complex with phenanthroline is a dinuclear centrosymmetric dimeric cation, containing two L ligands along with two phenanthroline ligands and BF4 − anions. The coordination geometry of each Cu(II) ion can be described as an elongated square pyramid. MS-ESI spectroscopy indicated that [Cu2(L)2(phen)2](BF4)2 is mononuclear in DMSO solution. In vitro antibacterial and antifungal activity was tested against four Gram-positive, four Gram-negative bacteria and three fungal strains. Complexes showed significantly stronger antibacterial activities than parent ligands. The mononuclear phenanthroline complex in solution showed very good antimicrobial activity, which is comparable to the activity of the standard antibiotic amikacin against all tested bacterial strains. The same complex has better antifungal activity than fluconazole, which was used as a standard. Results of the brine shrimp test indicate that both complexes have good toxicity against Artemia nauplii.

We have synthesized and characterized Co(II) (1), Zn(II) (2), Fe(III) (3) and Cu(II) (4) complexes of 2,2'‐[2,6‐pyridinediylbis(ethylidyne‐1‐hydrazinyl‐2‐ylidene)]bis[N,N,N‐trimethyl‐2‐oxoethanaminium] dichloride (H2LCl2) by NMR, IR, and X‐Band EPR spectroscopy, respectively, as well as by single‐crystal X‐ray structural analysis. H2LCl2 belongs to the class of diacetylpyridine bis(hydrazone) ligands and bears two positively charged quaternary ammonium functionalities. The complexes 1–3 possess a pentagonal‐bipyramidal geometry, whereas 4 has square‐pyramidal geometry. Redox reactivity and SOD activity of the complexes was studied by means of electrochemical measurements in aqueous‐buffer and DMF or DMSO solutions, respectively, as well as by stopped‐flow measurements. Complexes 1–3 do not have SOD activity, whereas 4 exhibits a high catalytic rate constant for the superoxide dismutation, kcat = 1.73 × 107 m–1 s–1 (in MOPS buffer solution of pH = 7.4). The results were discussed in terms of complex redox potentials, electrostatic interactions and their spatial distribution, kinetic lability of metal centers, and stability of peroxo intermediates, respectively.

Two Co(III) complexes with condensation product of thiosemicarbazide and 2-acetylthiazole (HL1 ligand, (E)-2-(1-(thiazol-2-yl)ethylidene)hydrazine-1-carbothioamide) and the condensation product of 2-acetylpyridine and Girard's P reagent (HL2Cl ligand, (E)-1-(2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethyl)pyridin-1-ium chloride) have been synthesized and characterized based on the results of single-crystal X-ray diffraction, NMR and IR spectroscopy and elemental analysis. Cobalt(III) complex with HL1 ligand, [Co(L1)2]BF4⋅H2O (1), is bis octahedral complex in which two deprotonated ligand molecules coordinate in a mer arrangement through two NNS sets of donor atoms. In cobalt(III) complex with HL2Cl, [Co(L2)(N3)3] (2), the ligand is coordinated in deprotonated, formally neutral, form to Co(III) ion in tridentate fashion through NNO set of donor atoms, and the other three coordination sites of a monokis octahedron are occupied by meridionally coordinated azide anions. DFT calculations were performed to elucidate coordination preferences of these ligands toward Co(III) ion.

The reaction of (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium-chloride (HLCl) with copper(II) perchlorate led to mononuclear [CuLCl]ClO 4 complex (1). The same reaction with excess of sodium azide gives dinuclear azido double end-on bridged Cu(II) complex [Cu 2 L 2 (μ- 1,1 -N 3 ) 2 ](ClO 4 ) 2 (2). In both complexes hydrazone ligand is NNO coordinated in monodeprotonated formally neutral zwitter-ionic form. Complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray crystallography. Variable‐temperature magnetic susceptibility measurements for dinuclear Cu(II) complex showed intra-dimer ferromagnetic coupling between Cu(II) ions (J = 7.4 cm −1 ). DFT-BS calculations provided explanation for magnetic properties of dinuclear Cu(II) complex. Both complexes were shown to highly efficiently catalyze the N-arylation of imidazole and benzimidazole with electron-poor or electron-rich aryl iodides, under user-friendly and sustainable conditions.

U ovom radu opisani su sinteza, strukturna karakterizacija i teorijski proračuni za komplekse Co(II), Ni(II), Zn(II) i Cd(II) sa kondenzacionim proizvodom 2-hinolinkarbaldehida i Žirarovog T reagensa. Za dinuklearne komplekse Co(II) i Ni(II) i mononuklearni Co(II) kompleks urađena su i magnetna merenja..., In this work the synthesis, structural characterization and theoretical calculations for the Co(II), Ni(II), Zn(II), and Cd(II) complexes with the condensation product of 2-quinolinecarboxaldehyde and the Girard’ T reagent are described. Magnetic measurements were performed for the dinuclear Co(II) and Ni(II) complexes and mononuclear Co(II) complex...

U potrazi za biološki aktivnim jedinjenjima, počev od progesterona i 3-okso-α,β-nezasićenih androstenskih steroida, u okviru ove disertacije sintetisano je i potpunookarakterisano pedeset novih derivata steroidnih hidrazona, od kojih po jedanaesttiosemikarbazona, tijadiazolina i semikarbazona, dvanaest tiazolidin-4-ona i petkarbazatnih estara.Po prvi put je urađena detaljna analiza stereohemije steroidnih hidrazona u položajimaC-3/17 androstenskih, odnosno C-3/20 progesteronskih derivata. Struktura istereohemija potvrđene su rezultatima rendgenske strukturne analize za tijadiazolin 7a,prvo okarakterisano steroidno jedinjenje koje sadrži šestočlani ugljenični prstenkondenzovan sa spiro-tijadiazolinskim prstenom, i tiazolidinon 9b-E, prvi steroidniderivat sa poznatom konfiguracijom dvostruke veze u položaju C-3 hidrazonotiazolidin-4-onskog fragmenta.Sintetisana jedinjenja su ispoljila najjaču citotoksičnost prema HeLa ćelijamaadenokarcinoma cerviksa i prema K562 ćelijama hronične mijeloidne leukemije, a posvojoj aktivnosti istakli su se tiosemikarbazoni 2a, 2b, 2c i 2f, tijadiazolini 8a i 8e itiazolidin-4-oni 9a i 10a. Pritom su koeficijenti selektivnosti u antikancerskom dejstvuprema malignim ćelijama u odnosu na normalne humane PBMC, kako na nestimulisanetako i na mitogenom stimulisane, bili daleko veći od vrednosti 2,5 što ova jedinjenjasvrstava u potencijalne kandidate za in vivo ispitivanja. Sumporni derivati bili su dalekoaktivniji od kiseoničnih. Najaktivniji derivati indukovali su apoptozu posredstvomkaspaza-3, -8 i -9 i inhibirali angiogezu in vitro zbog čega se smatra da posedujuznačajan antikancerski potencijal., Searching for biologically active compounds, within this doctoraldissertation fifty new steroidal hydrazone derivatives, of which 11 thiosemicarbazones,11 thiadiazolines, 12 thiazolidin-4-ones, 11 semicarbazones and 5 carbazate esters, weresynthesized starting with progesterone and 3-oxo-α,β-unsaturated androstene steroids,and fully characterized.For the first time, detailed stereochemistry analyses of steroidal hydrazones in the C-3/17 positions of androstene derivatives, or C-3/20 positions of progesterone derivativeswas done. Structure and stereochemistry were confirmed by the results of X-rayanalyses for thiadiazoline 7a, the first characterized steroid compound that contains sixmemberedcarbon ring condensed with the spiro-thiadiazoline ring, and thiazolidinone9b-E, the first steroidal derivative with known configuration of double bond in C-3position of the hydrazono-thiazolidin-4-one fragment.Synthesised compounds manifested the best cytotoxicity towards HeLa cervixadenocarcinoma cells, and K562 cells of chronic myeloide leukemia, the best activitybeing showed by thiosemicarbazones 2a, 2b, 2c and 2f, thiadiazolines 8a and 8e, andthiazolidin-4-ones 9a and 10a. All of these compounds exhibited considerably higherintensities of cytotoxic action against malignant cells when compared with normalhuman PBMC, both resting and mitogen-stimulated, with coefficient of selectivityhigher than 2.5, which makes these compounds potential candidates for in vivoexperiments. Sulfur derivatives were much more active than oxygen derivatives. Themost active derivatives induced apoptosis mediated by caspase-3, -8 and -9, and theyinhibited angiogenesis in vitro, because of what they are considered to have significantanticancer potential.

Сумпор-сумпор интеракције су препознате у многим молекулским системима, где су одговорне за молекулску структуру и функцију многих познатих неорганских и органских материјала као и протеина. У овој докторској дисертацији проучаване су геометрије и енергије сумпор-сумпор интеракција анализом података из кристалних структура и применом квантнохемијских прорачуна високог нивоа теорије..., Sulfur-sulfur interactions have been recognized in various molecular systems, where they are responsible for the molecular structure and function of many well known inorganic and organic moleculs and proteins. This doctoral study investigates the geometries and energies of sulfur-sulfur interactions by analyzing data obtained from crystal structures and by high-level quantum chemical calculations...

Magnetic anisotropy in pentagonal bipyramidal complexes of Co(II) (1 and 2), Fe(III) (3 and 4), and Ni(II) (5) with a 2,2′-[2,6-pyridinediylbis(ethylidyne-1-hydrazinyl-2-ylidene)]bis[N,N,N-trimethyl-2-oxoethanaminium] equatorial ligand and isothiocyanato axial ligands has been investigated by magnetic susceptibility measurements, powder X-band electron paramagnetic resonance (EPR) spectroscopy, Mössbauer spectroscopy, ab initio, and ligand-field density functional theory (LFDFT) calculations. The studied complexes display three distinct types of magnetic anisotropy. Co(II) complexes (1 and 2) show an easy plane anisotropy with large and positive D values and negligible rhombicity. The Ni(II) complex (5) has uniaxial magnetic anisotropy with a negative D value. Fe(III) complexes (3 and 4) have small zero-field splitting (ZFS) parameters. Theoretical modeling is used to rationalize the magnetic anisotropy in these systems and to identify the most important excited states that are responsible for the zero-field splitting. These excitations are a consequence of the electronic structure of the central metal ion in ideal pentagonal bipyramidal coordination.

In solid-state coordination chemistry, the coordination number of a metal center is not always unambiguously determined, as sometimes from the geometrical parameters it is not clear if ligands are directly bound to the central metal ion or they belong to the outer sphere of a complex. The nature of bonding between Cu(II) and weakly coordinated anions BF4–, NO3–, and ClO4– is investigated by the combined crystallographic and computational study. It is shown that the synergy between the crystal structure determination and computational chemistry allows identification of all interactions present in crystals. Three new complexes, [CuLCl]BF4 (1), [CuLCl]NO3 (2), and [Cu2L2Cl2](BF4)2 (3) with the same [CuLCl]+ moiety (L = (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-amin), were synthesized and characterized by single crystal X-ray diffraction methods and compared to the previously reported [CuLCl]ClO4 (4). Energy decomposition analysis, noncovalent interaction index analysis, independent gradient model, and the quantum theory of atoms in molecules are performed on the X-ray structures of these four complexes. The results revealed that in 1, 2, and 4, BF4–, NO3–, and ClO4– are weakly, but directly coordinated to the Cu(II) with bonds having high electrostatic character. In 3, BF4– is the counter-anion, electrostatically bonded to the L. Furthermore, the present analysis rationalized the fact that only complex 3 is binuclear with bridging Cl– ions.

U ovoj tezi ispitivane su antioksidativne aktivnosti (AA) slobodnih aminokiselina (glicin, alanin, prolin, valin, izoleucin, leucin, fenilalanin, triptofan, tirozin, serin, treonin, asparagin, glutamin, histidin, asparaginska kiselina, glutaminska kiselina, lizin, arginin, cistein i metionin, homocistein, hidroksiprolin, norleucin, 2-aminobutanska kiselina i 3,4-dihidroksifenilalanin) u Fentonovom sistemu. Redosled reaktivnosti aminokiselina u reakciji sa hidroksil-radikalom, antioksidativne aktivnosti (HO•) bio je sledeći: Trp > norleucin > Phe, Leu > Ile > His >3,4-dihidroksifenilalanin, Arg > Val > Lys, Tyr, Pro > hidroksiprolin > α-aminobutanska kiselina > Gln, Thr, Ser > Glu, Ala, Gly, Asn, Asp. Aminokiseline koje sadrže sumpor su u reakciji sa hidroksil-radikalom davale više različitih radikalskih vrsta koje su ispitivane EPR metodom sa spinskim hvatačima..., In this thesis antioxidative activities (AA) of free L-amino acids (glycine, alanine, proline, valine, isoleucine, leucine, phenylalanine, tryptophane, tyrosine, serine, threonine, asparagine, glutamine, histidine, aspartic acid, glutamic acid, lysine, arginine, cystein and methionine, homocysteine, hydroxyproline, norleucine, α-aminobutyric acid and 3,4-dihydroxyphenylalanine) against Fenton system-mediated hydroxyl radical (HO•) production in aqueous solution were studied. The rank order according to AA was: Trp > norleucine > Phe, Leu > Ile > His >3,4-dihydroxyphenylalanine, Arg > Val > Lys, Tyr, Pro > hydroxyproline> α-aminobutyric acid > Gln, Thr, Ser > Glu, Ala, Gly, Asn, Asp. Sulfur-containing FAA generated different secondary reactive products, which were discriminated by the means of electron paramagnetic resonance spin-trapping spectroscopy...

A tridentate NNO condensation product of 2-quinolinecarboxaldehyde and Girard's T reagent (HLC1) in the presence of azide ions coordinates with cobalt(II) giving mononuclear azido Co(II) complex [CoHL (N-3)(3)](1) as a main product and dinuclear end-on azido bridged Co(II) complex [Co2L2(mu-(1,1)-N-3)(2)(N-3)(2)] (2) in traces. Crystal structures of both complexes were determined. Variable temperature magnetic susceptibility measurement studies of complex I showed that Co(II) cation is in the low-spin state with t(2g)(6)e(g)(1) (S = 1/2) configuration. DFT-BS calculations for complex 2 anticipated ferromagnetic type interaction between paramagnetic centers (J = 53 cm(-1)). (C) 2017 Elsevier Ltd. All rights reserved.

The mixed chloride-azide [ZnL(N-3)(1.65)Cl-0.35] (1) and chloride-isocyanate [CdL(NCO)(1.64)Cl-0.36] (2) complexes with the condensation product of 2-quinolinecarboxaldehyde and trimethylammonium aceto-hydrazide chloride (Girard's T reagent) (HLCl) have been prepared and characterized by X-ray crystallography. In complexes 1 and 2, Znl and Cd1 ions, respectively, are five-coordinated in a distorted square based pyramidal geometry with NNO set of donor atoms of deprotonated hydrazone ligand and two monodentate ligands N-3(-) and/or N-3(-) and Cl- in the case of I and OCN- and/or OCN- and Cl- in the case of 2. The structural parameters of 1 and 2 have been discussed in relation to those of previously reported M(II) complexes with the same hydrazone ligand. Density functional theory calculations have been employed to study the interaction between the Zn2+ and Cd2+ ions and ligands. High affinity of ligands towards the Zn2+ and Cd2+ ions are predicted for both complexes. (C) 2018 Elsevier B.V. All rights reserved.

Pseudohalide metal complexes with hydrazones of the Girard T reagent are reviewed with respect to their synthesis, characterization, structures (both in solution and in the solid state), and magnetic properties. It is hoped that this microreview might serve as a concise guide to the chemistry of pseudohalide metal complexes with hydrazones of the Girard T reagent.

Octahedral Co(III) complexes with heteroaromatic hydrazones ((E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride and (E)-2-(1-(thiazol-2-yl)ethylidene)hydrazine-1-carbothioamide) and tetraisothiocyanato Co(II) complex anions have been synthesized, characterized by elemental analysis, IR and NMR spectroscopy, single-crystal X-ray diffraction and magnetic measurements. NMR spectroscopy showed that octahedral Co(III) complex cations of both compounds are stable in DMSO solution. Measured effective magnetic moments, which completely originates from complex anion [Co(NCS)4]2– are practically constant and very close to the expected value for Co2+ ion with spin S = 3/2 and completely quenched orbital angular momentum. Co(III) ions in octahedral complex cations are in a low spin magnetic state with S = 0 and do not contribute to the magnetic signal. © 2018 Elsevier Ltd