Browsing by Author "Marinova P."
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Item Crystal Structure of N-(2-Benzoyl-4,5-dimethoxyphenethyl)-2-phenylacetamide(2022-06-01) Marinova P.; Nikolova S.; Dołęga A.; Ahmedova A.The crystal structure of N-(2-benzoyl-4,5-dimethoxyphenethyl)-2-phenylacetamide indi-cates that the compound crystallizes in the monoclinic C2/c space group with eight molecules in the unit cell. The heteroatoms from the amide group form a chain of intermolecular N-H ··· O hydrogen bonds propagating along the b axis. The carbonyl group from the benzoyl substituent participates in short contacts with two H-atoms from the ethyl or phenyl groups.Item Investigation of the Complexation Activity of 2,4-Dithiouracil with Au(III) and Cu(II) and Biological Activity of the Newly Formed Complexes(2024-08-01) Marinova P.; Stoitsov D.; Burdzhiev N.; Tsoneva S.; Blazheva D.; Slavchev A.; Varbanova E.; Penchev P.The goal of this study is to synthesize, determine the structure, and examine the antimicrobial properties of novel Cu(II) and Au(III) complexes of 2,4-dithiouracil and its derivatives. These complexes were obtained by mixing aqueous solutions of the corresponding metal salts with the ligand dissolved in DMSO and aqueous NaOH, using a metal-to-ligand ratio of 1:4:2. The structures of the new compounds were analyzed by melting point determination, microwave plasma atomic emission spectrometry (MP-AES) for Cu and Au, inductively coupled plasma optical emission spectrometry (ICP-OES) for S, attenuated total reflection (ATR), solution and solid-state NMR, and Raman spectroscopy. The data for 2,4-dithiouracil obtained from the 1H NMR, 13C NMR, distortionless enhancement by polarization transfer spectrum (DEPT-135), proton–proton homonuclear correlation spectrum (1H-1H COSY), long-range 1H-13C heteronuclear multiple bond correlation experiment (HMBC), and heteronuclear single quantum coherence spectra (HSQC) aided the interpretation of the NMR data for the gold and copper complexes. Furthermore, the antimicrobial effect of the free ligands and their complexes was assessed against Gram-positive and Gram-negative bacteria, as well as yeasts.Item New platinum(II) complexes of cycloalkanespiro-5-(2-thiohydantoins). Synthesis and quantum chemical investigation(2015-01-01) Marinova P.; Marinov M.; Delchev V.; Stoyanov N.Synthesis and characterization of new Pt(II) complexes of cyclohexanespiro-5-(2-thiohydantoin) (L1) and cyclohepta-nespiro-5-(2-thiohydantoin) (L2) are discussed. The new complexes are studied by elemental analysis, IR and 1H NMR spectroscopy. The free ligands are investigated by UV-Vis, IR, 1H NMR, 13C NMR and Raman spectroscopy. The ground-state equilibrium geometries of the ligands L1 and L2 and their complexes with Pt(II) are optimized at the BLYP/CEP-31G theoretical level.Item Study on the synthesis, characterization and bioactivities of 3-methyl-9'-fluorenespiro-5-hydantoin(2016-01-01) Marinova P.; Marinov M.; Kazakova M.; Feodorova Y.; Slavchev A.; Blazheva D.; Georgiev D.; Penchev P.; Sarafian V.; Stoyanov N.This work describes a method for synthesis, as well as in vitro antiproliferative and antibacterial investigation of 3-methyl-9'-fluorenespiro-5-hydantoin. The structure of the substituted fluorenylspirohydantoin derivative was verified by UV-Vis, FT-IR, Raman, 1H NMR and 13C NMR spectroscopy, and by using a combination of 2D NMR experiments, which included 1H-1H COSY, HMQC and HMBC sequences. The geometry of the compound was optimized by the B3LYP density functional with 6-31G(d) basis set and the 1H and 13C NMR spectra were predicted with the HF/6-31G(d) calculations at the optimized geometry. The anticancer activity of the 3-methyl-9'-fluorenespiro-5-hydantoin was determined in suspension cell lines originating from tumors in humans (WERI-Rb-1). The cytotoxic effect was evaluated by WST-assay (Roche Applied Science). The antimicrobial effect of the compound against Gram-negative, Gram-positive bacteria and the yeast Candida albicans was investigated.Item Synthesis and Antibacterial Studies of a New Au(III) Complex with 6-Methyl-2-Thioxo-2,3-Dihydropyrimidin-4(1H)-One(2024-06-01) Marinova P.; Burdzhiev N.; Blazheva D.; Slavchev A.This article describes the synthesis of a new metal complex using 6-methyl-2-thioxo-2,3-dihydropyrimidin-4(1H)-one. The compound was analyzed using several methods, including determining its melting point and employing UV-Vis, IR, ATR, 1H NMR, HSQC, and Raman spectroscopy for the free ligand. The metal complex was formed by combining aqueous solutions of metal salts with the ligand dissolved in DMSO and water, along with NaOH in a metal-to-ligand-to-base ratio of 1:4:2. The NMR signals of the ligand were assigned using 1H-1H COSY, DEPT-135, HMBC, and HMQC spectra. Furthermore, the compound’s antimicrobial activity against Gram-positive and Gram-negative bacteria, as well as yeasts, was assessed.Item Synthesis and antimicrobial study of new Pt(IV) and Ru(III) complexes of fluorenylspirohydantoins(2019-01-01) Marinova P.; Marinov M.; Georgiev D.; Becheva M.; Penchev P.; Stoyanov N.The present work presents a synthesis, characterization and antimicrobial activitiy of new Pt(IV) and Ru(III) complexes of (9’-fluorene)-spiro-5-hydantoin (HL1) and (9’-fluorene)-spiro-5-(2-thiohydantoin) (HL2). The complexes were investigated by elemental analysis, UV-Vis and IR spectroscopy. The free ligands were studied by UV-Vis, IR, 1H NMR, 13C NMR and Raman spectroscopy. The antimicrobial tests of HL1 showed week bacteriostatic effect against Staphylococcus aureus ATCC 6538. The results for [Pt(L1)2(H2O)2(OH-)2] complex showed a good antimicrobial activity against Esсherichia coli ATCC 8739, Bacillus licheniformis ATCC 6633, S. aureus and the absence of such effect on the yeasts. The HL2 and its [Pt(L2)2(H2O)2(OH-)2] and [Ru(L2)3(H2O)3] complexes do not possess antimicrobial activity against the tested bacteria and yeasts.Item Synthesis and Biological Activities of Some Metal Complexes of Peptides: A Review(2024-06-01) Marinova P.; Tamahkyarova K.Peptides, both natural and synthetic, are well suited for a wide range of purposes and offer versatile applications in different fields such as biocatalysts, injectable hydrogels, tumor treatment, and drug delivery. The research of the better part of the cited papers was conducted using various database platforms such as MetalPDB. The rising prominence of therapeutic peptides encompasses anticancer, antiviral, antimicrobial, and anti-neurodegenerative properties. The metals Na, K, Mg, Ca, Fe, Mn, Co, Cu, Zn, and Mo are ten of the twenty elements that are considered essential for life. Crucial for understanding the biological role of metals is the exploration of metal-bound proteins and peptides. Aside from essential metals, there are other non-essential metals that also interact biologically, exhibiting either therapeutic or toxic effects. Irregularities in metal binding contribute to diseases like Alzheimer’s, neurodegenerative disorders, Wilson’s, and Menkes disease. Certain metal complexes have potential applications as radiopharmaceuticals. The examination of these complexes was achieved by preforming UV–Vis, IR, EPR, NMR spectroscopy, and X-ray analysis. This summary, although unable to cover all of the studies in the field, offers a review of the ongoing experimentation and is a basis for new ideas, as well as strategies to explore and gain knowledge from the extensive realm of peptide-chelated metals and biotechnologies.Item Synthesis and Biological Activity of Novel Complexes with Anthranilic Acid and Its Analogues(2023-08-01) Marinova P.; Hristov M.Item Synthesis and in vitro activity of platinum(II) complexes of two fluorenylspirohydantoins against a human tumour cell line(2014-01-01) Marinova P.; Marinov M.; Kazakova M.; Feodorova Y.; Penchev P.; Sarafian V.; Stoyanov N.This paper presents a method for synthesis and cytotoxicity of new platinum(II) complexes of (9′-fluorene)-spiro-5-hydantoin (L1) and (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2). The new obtained complexes were studied by elemental analysis: ultraviolet-visible, attenuated total reflection Fourier transform infrared (ATR-FTIR), and 1H- and 13C-NMR for Pt(II) compounds and additionally Raman spectroscopy for free ligands. Based on the experimental data, the most probable structure of the complexes is suggested. In the present study, we have examined cytotoxic activity of (9′-fluorene)-spiro-5-hydantoin (L1) and (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2) and their Pt(II) complexes on the retinoblastoma cell line WERI-Rb-1. © 2014 The Author(s). Published by Taylor & Francis.Item Synthesis of N-[1-(2-Acetyl-4,5-dimethoxyphenyl)propan-2-yl]benzamide and Its Copper(II) Complex(2023-01-01) Marinova P.; Nikolova S.; Tsoneva S.Abstract: This paper represents a convenient method for the synthesis of N-[1-(2-acetyl-4,5-dimethoxyphenyl)propan-2-yl]benzamide and its Cu(II) complex. In silico analysis predicted spasmolytic activity for the compound. Based on the in silico calculations, the importance of the predicted ketoamide, and our previous experiments, we synthesized the ketoamide via ortho-acylation of N-[1-(3,4-dimethoxyphenyl)propan-2-yl]benzamide with acetic anhydride in polyphosphoric acid. We applied the title ketoamide in reaction with Cu(II) varying the solvents. We found that the reaction leads to the formation of a coordination compound when the ligand dissolved in DMSO reacts with a water solution of CuCl2 in an alkaline environment in a molar ratio M : L : OH– = 1 : 2 : 2. The structures of the new compounds are discussed based on their melting points, IR, 1H, 13C NMR and Raman spectral data.Item Synthesis, characterization and spectroscopic properties of some 2-substituted 1,3-indandiones and their metal complexes(2009-07-10) Ahmedova A.; Atanasov V.; Marinova P.; Stoyanov N.; Mitewa M.New 2-acyl-1,3-indandione derivatives, compounds 1-4, were obtained by condensation of 2-acetyl-1,3-indandione with benzaldehyde, thiophene-2-aldehyde, thiophene-3-aldehyde and furane-2-aldehyde, respectively. The structures of the newly synthesized 2-substituted 1,3-indandiones were characterized by means of spectroscopic methods (FT-IR, 1H and 13C NMR, UV-Vis and MS). Based on the obtained results it is suggested that the compounds exist in the exocyclic enolic form. Mass spectral fragmentation paths are also proposed. In order to verify the possibility for tautomerization processes of the newly synthesized compounds their absorption spectra were recorded in various solvents. Furthermore, the complexation properties of the compounds with metal(II) ions were also studied. A series of non-charged complexes with Cu(II), Cd(II), Zn(II), Co(II) and Ni(II) was isolated and analyzed by elemental analyses and IR. The paramagnetic Cu(II) complexes were studied by EPR and distorted, flattened tetrahedral structures are predicted. The other metal complexes show the presence of water molecules, most probably coordinated to the metal ion, thus forming octahedral geometry. Ultimately, the studied properties of the newly synthesized compounds, 1-4, suggest that they may find application as extracting agents for metal ions, rather than as optical sensors. © Versita Warsaw and Springer-Verlag Berlin Heidelberg 2009.Item Synthesis, Characterization, and Antibacterial Studies of New Cu(II) and Pd(II) Complexes with 6-Methyl-2-Thiouracil and 6-Propyl-2-Thiouracil(2023-12-01) Marinova P.; Hristov M.; Tsoneva S.; Burdzhiev N.; Blazheva D.; Slavchev A.; Varbanova E.; Penchev P.The aim of the present study is to synthesize new metal complexes of 6-methyl-2-thiouracil and 6-propyl-2-thiouracil, elucidate their structures, and investigate their biological properties. All metal complexes were obtained after mixing water solutions of the corresponding metal salts and the ligand dissolved in DMSO and water solutions of NaOH in a metal-to-ligand ratio of 1:4:2. The structures of the new compounds are discussed based on melting point analysis (MP-AES) for Cu and Pd, UV-Vis, IR, ATR, 1H NMR, 13C NMR, and Raman spectroscopy. The interpretation of complex spectra is assisted by the data for 6-methyl-2-thiouracil and 6-propyl-2-thiouracil obtained from 1H-1H COSY, DEPT-135, HMBC and HMQC spectra. In addition, the antimicrobial activity of these complexes and the free ligands are assessed against both Gram-positive and Gram-negative bacteria, as well as yeasts. In general, the addition of metal ions improved the antimicrobial activity of both 6-methyl-2-thiouracil and 6-propyl-2-thiouracil. The Cu(II) complex with 6-methyl-2-thiouracil and the Pd(II) complex with 6-propyl-2-thiouracil exhibited the highest activity against the test microorganisms.Item Synthesis, Characterization, and Antibacterial Studies of New Cu(II) and Pd(II) Complexes with 6-Methyl-2-Thiouracil and 6-Propyl-2-Thiouracil(2023-12-01) Marinova P.; Hristov M.; Tsoneva S.; Burdzhiev N.; Blazheva D.; Slavchev A.; Varbanova E.; Penchev P.The aim of the present study is to synthesize new metal complexes of 6-methyl-2-thiouracil and 6-propyl-2-thiouracil, elucidate their structures, and investigate their biological properties. All metal complexes were obtained after mixing water solutions of the corresponding metal salts and the ligand dissolved in DMSO and water solutions of NaOH in a metal-to-ligand ratio of 1:4:2. The structures of the new compounds are discussed based on melting point analysis (MP-AES) for Cu and Pd, UV-Vis, IR, ATR, 1H NMR, 13C NMR, and Raman spectroscopy. The interpretation of complex spectra is assisted by the data for 6-methyl-2-thiouracil and 6-propyl-2-thiouracil obtained from 1H-1H COSY, DEPT-135, HMBC and HMQC spectra. In addition, the antimicrobial activity of these complexes and the free ligands are assessed against both Gram-positive and Gram-negative bacteria, as well as yeasts. In general, the addition of metal ions improved the antimicrobial activity of both 6-methyl-2-thiouracil and 6-propyl-2-thiouracil. The Cu(II) complex with 6-methyl-2-thiouracil and the Pd(II) complex with 6-propyl-2-thiouracil exhibited the highest activity against the test microorganisms.