Barbara Miroslaw

Disubstituted thiourea derivatives and their activity on CNS: Synthesis and biological evaluation

A series of new thiourea derivatives of 1,2,4-triazole have been synthesized. The difference in structures of obtained compounds are directly connected with the kind of isothiocyanate (aryl/alkyl). The (1)H NMR, (13)C NMR, MS methods were used to confirm structures of obtained thiourea derivatives. The molecular structure of (1, 17) was determined by an X-ray analysis. Two of the new compounds (8 and 14) were tested for their pharmacological activity on animal central nervous system (CNS) in behavioural animal tests. The results presented in this work indicate the possible involvement of the serotonergic system in the activity of 8 and 14. In the case of 14 is also a possible link between its activity and the endogenous opioid system. All obtained compounds were tested for antibacterial activity against gram-positive cocci, gram-negative rods and antifungal activity. Compounds (1, 2, 5, 7, 9) showed significant inhibition against gram-positive cocci. Microbiological evaluation was carried out over 20 standard strains and 30 hospital strains. Selected compounds (1-13) were examined for cytotoxicity, antitumor, and anti-HIV activity.

4-Azatricyclo[5.2.2.02,6]undecane-3,5,8-triones as Potential Pharmacological Agents

A series of twenty six arylpiperazine and aminoalkanol derivatives of 4-aza-tricyclo[5.2.2.02,6]undecane-3,5,8-trione have been prepared. The synthesized compounds were evaluated for their cytotoxicity and anti-HIV-1 activity in MT-4 cells.

Vibrational spectroscopy (FT-IR and Laser-Raman) investigation, and computational (M06-2X and B3LYP) analysis on the structure of 4-(3-fluorophenyl)-1-(propan-2-ylidene)-thiosemicarbazone.

In this study, the experimental and theoretical vibrational spectral analysis of 4-(3-fluorophenyl)-1-(propan-2-ylidene)-thiosemicarbazone have been carried out. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) have been recorded for the solid state samples. The theoretical vibrational frequencies and the optimized geometric parameters (bond lengths and angles) have been calculated for gas phase using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with 6-311++G(d,p) basis set. The diversity in molecular geometry of fluorophenyl substituted thiosemicarbazones has been discussed based on the X-ray crystal structure reports and theoretical calculation results from the literature. The assignments of the vibrational frequencies have been done on the basis of potential energy distribution (PED) analysis by using VEDA4 software. A good correlation was found between the computed and experimental geometric and vibrational data. In addition, the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbital energy levels and other related molecular energy values of the compound have been determined using the same level of theoretical calculations.

Synthesis and characterization of CuII–LnIII (Ln = Ho, Tm, Yb, or Lu) complexes with N2O4-donor Schiff base ligand

The heterodinuclear complexes [CuLnL(NO3)2(H2O)3MeOH]NO3·MeOH (Ln = Ho (1), Tm (2), Yb (3), and Lu (4); L = N,N′-bis(5-bromo-3-methoxysalicylidene)propylene-1,3-diamine) have been synthesized and characterized by elemental analysis, FTIR, thermogravimetric (TG)/differential scanning calorimetry (DSC), TG-FTIR, single crystal X-ray diffraction studies, and magnetic measurements. The isostructural compounds crystallized in the monoclinic space group P21/n. The rare earth(III) cation is nine coordinate, whereas the coordination number for copper(II) is six. The complexes were stable at room temperature. The thermal decomposition products were mainly CH3OH, H2O, CH3Br, NOx (x = 1 or 2), CO2, and CO. The magnetic properties of 1–3 were dominated by the crystal field effect on the LnIII site, masking the magnetic interaction between the paramagnetic centers. The CuII–LuIII pair in 4 showed no significant interaction, which is in accord with the diamagnetic nature of the ground state for lutetium(III). Graphical Abstract The heterodinuclear compounds [CuLn(L)(NO3)2(H2O)3MeOH]NO3·MeOH (where Ln = Ho (1), Tm (2), Yb (3), and Lu (4)) have been synthesized and characterized by elemental analysis, FTIR, TG/DSC, TG-FTIR, single crystal X-ray diffraction studies, and magnetic measurements. The complexes are isostructural and crystallize in the monoclinic space group P21/n. The magnetic properties of 1, 2, and 3 are dominated by the crystal field effect on the LnIII site, masking the magnetic interaction between the paramagnetic centers.

Unexpected course of reaction between (E)-2-aryl-1-cyano-1-nitroethenes and diazafluorene: why is there no 1,3-dipolar cycloaddition?

Reactions between (E)-2-aryl-1-cyano-1-nitroethenes and diazafluorene lead to acyclic 2,3-diazabuta-1,3-diene derivatives, instead of the expected pyrazoline systems. DFT calculations suggest that this is a consequence of formation of zwitterionic structure in the first stage of the reaction. It must be noted that this is a specific property of the (E)-2-aryl-1-cyano-1-nitroethenes group, in contrast to most other conjugated nitroalkenes.Graphical abstract

Synthesis, antibacterial and antiproliferative potential of some new 1-pyridinecarbonyl-4-substituted thiosemicarbazide derivatives

In this study, the antibacterial, cytotoxic and antiproliferative activities of novel thiosemicarbazide derivatives were assessed. Our results demonstrated that some of the novel compounds possess good antibacterial properties against Staphylococcus epidermidis, Streptococcus mutans and Streptococcussanguinis and are only slightly cytotoxic; thus, they exhibit an excellent therapeutic index, which is higher than that of ethacridine lactate. Moreover, our data showed that compounds 2 and 4 have an antiproliferative activity against human breast adenocarcinoma and human hepatocellular carcinoma cell lines. We expect that the novel thiosemicarbazide derivatives can be used as agents for treatment of dental caries and also for chemotherapy support.

A simple and easy way to enhance sensitivity of Sn(IV) on bismuth film electrodes with the use of a mediator

For the first time an in situ-plated bismuth film electrode prepared with the use of a reversibly deposited mediator (Zn) was applied to anodic stripping voltammetry of the metal ions. This simple and easy way of the electrode surface modification by metal films was suggested to increase the voltammetric signal of Sn(IV) and, consequently, to improve the sensitivity and tin detection limit. The structural and chemical information about the bismuth films plated with and without the use of the mediator were derived from AFM and XPS data analysis.Graphical abstract

Antimicrobial and Anti-biofilm Activity of Thiourea Derivatives Bearing 3-amino-1H-1,2,4-triazole Scaffold

A set of 21 thiourea derivatives were prepared through reacting 3-amino-1H-1,2,4-triazole with the commercial aliphatic and aromatic isothiocyanates. The aliphatic isothiocyanate was used as reagent leading to substitution on NH atom of 3-aminotriazole ring, whereas the triazole amino group was substituted when isothiocyanate group was bonded to the Csp2 hybridized atom, e.g. an aryl or C=O fragment. All compounds were evaluated in vitro for the antimicrobial activity. The derivatives 1, 2, 4, 8, 9, 10 and 12 showed the highest inhibition against Gram-positive cocci (S. aureus and S. epidermidis). The observed MIC values were in the range of 4-32 μg/mL. Compounds were also tested for their in vitro antimicrobial activity against the hospital methicillin-resistant strains of S. aureus. The observed MIC values varied from 4 to 64 μg/mL. The products 4 and 10 effectively inhibited the formation of biofilms of the methicillin-resistant and standard strains of S. epidermidis. The compound 10 was found to be more promising with IC50 values of 2-6 μg/mL as compared to the control. Moreover, the cytotoxicity against the MT-4 cells of all studied thioureas was evaluated. The compound 18 was significantly cytotoxic (CC50 = 8 μM).

Asymmetry in propeller-like trinuclear diphenoxo-bridged CuII–LnIII–CuII (Ln = La, Pr, Nd) Schiff base complexes – synthesis, structure and magnetic properties

Neutral heterotrinuclear complexes 2{[Cu2Ln(H2L)2(NO3)3]}·6CH3OH (Ln = La (1), Nd (2)) and [Cu2Ln(H2L)2(NO3)3]·4CH3OH·2H2O (Ln = Pr (3)) were obtained in the reaction of N,N′-bis(2,3-dihydroxybenzylidene)-1,3-diaminopropane (H4L = C17H18N2O4) with the respective salts of LnIII and CuII. Compounds 1–3 have similar coordination units and display asymmetry in the degree of planarity of the bridging CuO2Ln fragments, which is unusual for CuII–LnIII–CuII complexes. The geometry of the obtained complexes has been compared to the structural data of other 3d–4f–3d trinuclear diphenoxo-bridged complexes. The temperature dependence of the magnetic susceptibility and the field-dependent magnetization indicate that the interaction between CuII and LnIII ions is antiferromagnetic for Ln = Pr (2) and Nd (3), whereas in 1 the CuII–LaIII pairs show no significant interaction, which is in accord with the non-magnetic nature of the ground state for lanthanum(III).

Recurrent supramolecular motifs in discrete complexes and coordination polymers based on mercury halides: prevalence of chelate ring stacking and substituent effects

In recent years, the crystal engineering library has been enriched with a number of previously unrecognized or unnoticed intermolecular interactions, such as agostic, tetrel, chalcogen, pnicogen bonding and chelate ring stacking – collectively referred to as “unconventional interactions”. Many open questions remain unaddressed regarding their ability to form synthon interactions, specificity, and cooperativity, for example with π–π stacking interactions. In this work, we throw light on the formation of chelate ring stacking in metal–organic assemblies of nicotinohydrazide ligands (N′-(1-(2-pyridyl)ethylidene)nicotinohydrazide (HL) and N′-(phenyl(pyridin-2-yl)methylene)nicotinohydrazide (HL1)) with mercury(II) halide (HgBr2, HgI2) salts. Their reaction produced five compounds, namely [Hg(μ-L)BrHgBr2]n (1), [Hg(μ-L1)Br]n (2), [Hg(L)I2] (3), [Hg(HL1)I2]·(CH3OH) (4), and [Hg(μ-L1)I]n (5). Crystal structure analysis reveals that chelate ring stackings are formed in four of the reported metal–organic compounds, and are common also in the literature precedents. The energies of chelate ring stackings and π–π heterocycle stackings have been computed and analyzed by means of DFT calculations, and the results were verified using Baders theory of “atoms in molecules”. These results provide a rationale for preferential formation of both unconventional and conventional stackings and allow us to conclude that chelate ring interaction may be considered as a synthon interaction for nicotinohydrazide metal complexes. Interpretations for packing differences imposed by the substituent effect (substitution of methyl group in HL for phenyl group in HL1) were provided based on the Hirshfeld surface analysis and 2D fingerprint plots of the crystal structures reported here.