We have reported herein a simple and efficient synthesis method of thymyl ethers for structural modifications of natural products such as monoterpenoids and studies of ether derivatives of thymol in biological importance.The investigations showed that thymol reacts very smoothly with different types of substituted acetanilides.The synthesized compounds have been tested for their bacterial potency against four bacterial species. Such a structural modification will be beneficial in the field of pest management for designing the active molecules.

2,4,5-Trisubstituted imidazole derivatives with heteroaromatic groups are versatile heterocyclic compounds exhibiting a wide range of biological activities, as well as very interesting thermal, optical, electronic and redox properties. In the past years, this type of imidazole derivatives has been explored as optical colorimetric and fluorimetric chemosensors due to their ability to coordinate with ions with biological and environmental relevance.

In order to continue the work developed by the research group, we report the synthesis and characterization using usual spectroscopic techniques (NMR, absorption and emission spectroscopies) of a new imidazole derivative, substituted at position 2 of the imidazole with an 8-hydroxy-quinoline group. Furthermore, to complement the characterization of the synthesized imidazole compound, a preliminary study as an optical chemosensor was carried out in acetonitrile in the presence of ions with biological, medicinal and environmental relevance.

Small fluorescent molecules have emerged as essential tools for contemporary analytical methodologies applied in the biosciences field [1]. In this regard, 2-amino-3-carbonitrile presents a set of features that suits them as the best fluorescent probes for biological applications [2]. They are characterized by presenting high photostability, molar absorption molar coefficients, and modest Stokes shifts, great features for fluorescence applications [3,4]. As such, they have been used in covalent and non-covalent labeling of amino acids, proteins, DNA, among other biological materials [5, 6].

The observed shifts of the electronic absorption and emission bands of organic compounds induced by solvents are commonly understood as an indication of the extent of charge reorganization upon electronic excitation.

Considering all these facts, we are interested in the study of the effect of seven solvents of different polarities on the fluorescence of three derivatives of 2-amino-3-carbonitrile. The results recorded were reported using fluorescence microscopy analysis.

The three compounds under study display fluorescence with wavelength shifts between 350 and 437 nm. The results support the concept that associated the polarity of the compounds with the solvents.

N –Heterocyclic Carbenes (NHCs) have become one of the most popular organometallic ligands. A considerable attention has been paid to the synthesis NHCs complexes owing to their significant biological activity. Many compounds containing the moiety (NHCs) have shown capacity in biomedical applications, including as antimicrobial, Antiproliferative, anticancer, anti-HIV, antiseptic, antioxidants, anti-inflammatory, and as antitumor agents.

Many years ago the researchers discovered the bioorganometallic chemistry of the silver metal. On the other hand, there were an emergent number of publications have been widely studied bioorganometallic chemistry of the Ag (I) complexes of N - heterocyclic carbenes (NHCs). Silver (I)-NHC complexes used as potential curative applications, and also are useful as carbine transfer agents. For this reason we are interested to synthesize Silver (I)-NHC.

The synthesis and characterization of three tridentate ligands for new MOFs is described. A triple aminolysis of the 1,3,5-tribenzoyl chloride with p-aminobenzoic acid gave the tricarboxylic acid 1 in 90% yield. Moreover, the same reaction, also from the 1,3,5-tribenzoyl chloride, but using p-aminobenzonitrile gave the new tris-benzonitrile 2 in 85% yield. Finally, this later one was treated with sodium azide and a Lewis acid to synthesize the also new tris-tetrazole-based ligand 3 in 72% yield through a [3+2] azide-nitrile cycloaddition. It is noteworthy that the isosterism between carboxylic acids and tetrazoles may be considered to design and fabricate new MOFs with expected similar properties.

The development of compounds capable of recognizing ions with biological and environmental importance through optical signals (colorimetric and/or fluorimetric) is an attractive goal nowadays. Fluoride is an example of an anion harmful to human health at certain levels since its high intake can lead to chronic diseases such as dental and skeleton fluorosis, and metabolic dysfunctions. Thus, simple and rapid sensing tools to monitor fluoride levels in biological samples are of great importance. Boron-dipyrromethene (BODIPY) derivatives have received great attention for chemosensory applications due to their remarkable physical-chemical properties, such as high molar absorption coefficients, high quantum fluorescence yields, intense and narrow absorption/emission bands in the visible region of the electromagnetic spectrum, and good photochemical stability. Additionally, the BODIPY core can be easily functionalized to be used as selective chromo-fluorogenic chemosensor for various analytes. In continuation of the work developed in our research group, regarding chromofluorogenic chemosensors, we report the synthesis, spectroscopic characterization, and evaluation of the chemosensory ability of a novel BODIPY derivative functionalized with a carbazolyl group at the meso position as a fluorimetric chemosensor for the selective detection of fluoride.

Antibiotic resistance has become a serious global health problem in the 21st century requiring urgent remedial action, as high levels of resistance in several micro-organisms spread rapidly. This research seeks to identify a new molecule with inhibitory activity against DNA gyrase in Gram-negative microorganisms resistant to fluoroquinolones, through in silico models starting from a group of compounds designed in a previous study. AutoDock was used for the molecular docking of the 9 new molecules analogous to ciprofloxacin optimized through the semi-empirical method PM6, with gyrA Wild Type and Mutant Type of C. jejuni, E. coli, N. gonorrhoeae, P. aeruginosa, S. enteritidis and S. typhi; where the molecule with the highest affinity for the DNA gyrase was selected as the one with the best binding free energy parameters and inhibition constant, to estimate the spontaneity and the IC₅₀ of the process respectively. Subsequently, a retrospective docking was performed for the validation of the results obtained with the new molecules. Molecular docking results position Molecule 7 as the one with the highest affinity for gyrA in 5 microorganisms, with binding free energy values lower than -7.0 kcal/mol and small inhibition constant compared to those obtained in ciprofloxacin. Moreover, the validation of these results in the gyrA MT systems of S. typhi, E. coli and P. aeruginosa, suggest a good degree of reliability in the affinity shown by the new fluoroquinolones with their protein target. Finally, Molecule 7 is nominated as a potential drug with good antibacterial activity so that it can be evaluated in vitro.

The design and synthesis of colorimetric chemosensors for recognition of anions is an essential research topic since these negatively charged species display an important role in biomedical and environmental fields. Among optical chemosensors based on organic molecules, BODIPY is a multifaceted signaling scaffold which can be modified through chemical functionalization to modulate its photophysical properties and to introduce selective recognition sites for a higher target binding affinity. Moreover, benzimidazole and its derivatives have been investigated as anion and cation recognition systems that exhibit optical changes upon analyte complexation. As an extension of the work developed in our research group, we report the synthesis of a BODIPY functionalized with an anthracenyl group at meso position and a benzimidazole heterocycle at 2-position, for a selective colorimetric response towards hydrogensulfate anion (HSO₄^-). The recognition behavior of the BODIPY derivative was studied in aqueous acetonitrile/water (75:25) solutions in the presence of different anions and the results showed a specific color change of the solution of the BODIPY derivative upon interaction with HSO₄^-.

IDAS-CONICET, Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, X5804BYA Río Cuarto, Córdoba, Argentina.

Increasing of resistant bacteria to clinical antibiotics has conducted to establish new treatments for infections. One of them includes photodynamic inactivation of microorganisms. In general, the presence of positive charge precursor groups allows improving the photoinactivation due to an increase in interaction with microbial cells. In this context, 5,15-di(4-(N,N-dimethylaminophenyl)-10,20-di(pentafluorophenyl)porphyrin (1) and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (2) were synthesized from the condensation of 4-pentafluorobenzaldehyde and 5-(pentafluorophenyl)dipyrromethane or pyrrole catalysed by boron diethyl etherate in dichloromethane. After oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and purification using flash chromatography, porphyrin 1 and 2 were isolated in 24% and 36%, respectively. An aromatic nucleophilic substitution reaction was used to obtain conjugated polymers based in these porphyrins covalently linked to polyethylenimine (PEI-1 and PEI-2). The reaction was carried out in N,N-dimethylformamide (DMF) giving 100% conversion. After that, the solvent was removed by distillation under reduce pressure and the solid was washed with petroleum ether and drying in a vacuum oven. These conjugates showed the Soret absorption band and the four characteristic Q bands of porphyrins. Photodynamic studies indicated that PEI-2 is more effective than PEI-1 to produce singlet oxygen and decompose L-tryptophan with a significant contribution of a type II mechanism. In addition, in vitro PDI studies demonstrated that both polymers are effective phototherapeutic agents for the eradication of bacteria.

Bacterial infections have one of the extensive impacts on public health. Therefore, finding compounds with antibacterial properties could serve as an effective method. In this work, a nanocomposite, Ag/CaO was prepared from silver nitrate and egg shells. After calcination of the egg shells at 900°C, the solid remaining, CaO was cooled, then silver nitrate was added and the mixture was ground to a fine powder, and finally heated at 300°C. The brown solid obtained was characterized by SEM, XRD and XRF methods. Afterwards, the prepared Ag/CaO nanocomposite was applied and compared with CaO for antibacterial activity against gram positive and gram negative bacteria. The used bacteria were pseudomonas aeruginosa, keleb pneumonia, staphylococcus aureus, staph saprophyticus, Ecoli.