This account is intended to focus on recent developments in the syntheses and metal-catalysed asymmetric reactions of not only chiral pyridine-phosphines, but also of other chiral P,N-ligands in which the pyridine framework is part of more complex heterocycles, such as quinolines, isoquinolines, phenanthridines, etc. and the phosphorus atom belongs not only to simple phosphine functionalities, but also to other groups, such as phosphites, phosphoramides, etc.

Chiral P,N-ligands with pyridine-nitrogen and phosphorus donor atoms. Syntheses and applications in asymmetric catalysis: Tetrahedron report number 659

Synthesis, characterization, and biological activity of some novel Schiff bases and their Co(II) and Ni(II) complexes: A new route for Co 3 O 4 and NiO nanoparticles for photocatalytic degradation of methylene blue dye

Three new Schiff base compounds were synthesized via condensation of 3-R-4-amino-5-hydrazino-1,2,4-triazole with dibenzoylmethane [R = H, CH3, and CH2CH3 namely L1, L2, and L3, respectively]. The synthesized Schiff bases were characterized using melting point, CHN elemental analyses, FT-IR, and 1H-NMR. The corresponding Cu(II) Schiff base complexes were synthesized via refluxing the prepared Schiff bases with CuCl2·2H2O. The synthesized complexes have been characterized by means of different spectral tools (FT-IR, ESR, and UV–Vis spectra) in addition to elemental analysis, magnetic moment, conductivity, and thermal analysis. The synthesized copper complexes are nonelectrolytes in N,N-dimethylformamide (DMF) based on their conductance values. Using modified Bauer-Kirby method, the Schiff bases and their Cu(II) complexes have been tested for antifungal (Candida albicans and Aspergillus flavus) and antibacterial (Staphylococcus aureus and Escherichia coli) activities. Moreover, CuO nanoparticles were produced via thermal decomposition of the synthesized Cu(II) complexes at 650 °C. The produced nanoparticles were characterized using XRD, HR-TEM, FT-IR, and UV–Vis spectroscopy. The CuO nanostructures exhibited good photocatalytic activity for the degradation of methylene blue dye in the presence of hydrogen peroxide with 77.36% degradation efficiency in 360 min. Proposed structure of the synthesized Cu(II) complexes

Synthesis, Characterization and Biological Activity of New 3-substitued-4-amino-5-hydrazino-1,2,4-triazole Schiff Bases and Their Cu(II) Complexes: A New Approach to CuO Nanoparticles for Photocatalytic Degradation of Methylene Blue Dye

Synthesis, spectroscopic characterization, crystal structure, Hirshfeld surface analysis and antimicrobial activities of two triazole Schiff bases and their silver complexes

Periodontal diseases, such as gingivitis and periodontitis, are inflammatory diseases triggered by pathogenic bacteria that lead to damage of the soft tissue and bone supporting the teeth. Amongst the identified oral periodontopathogenic bacteria, Porphyromonas gingivalis is able to enhance oral dysbiosis, which is an imbalance in the beneficial commensal and periodontal pathogenic bacteria that induces chronic inflammation. Given the critical role of oral pathogenic bacteria like P. gingivalis in the pathogenesis of periodontitis, local and/or systemic antibacterial therapy has been suggested to treat this disease, especially in its severe or refractory forms. Nevertheless, the majority of the antibacterial agents currently used for the treatment of periodontal diseases are broad-spectrum, which harms beneficial bacterial species that are critical in health, inhibit the growth of pathogenic bacteria, contribute in protecting the periodontal tissues to damage and aid in its healing. Thus, the development of more effective and specific antibacterial agents is needed to control oral pathogens in a polymicrobial environment. The strategies for the development of novel antibacterial agents include natural product isolation as well as synthetic and semi-synthetic methodologies. This review presents an overview of the periodontal diseases gingivitis and periodontitis along with current antibacterial treatment options (i.e., classes of antibacterial agents and the mechanism(s) of resistance that hinder their usage) used in periodontal diseases that specifically target oral pathogens such as P. gingivalis. In addition, to help medicinal chemists gain a better understanding of potentially promising scaffolds, this review provides an in-depth coverage of the various families of small molecules that have been investigated as potential anti-P. gingivalis agents, including novel families of compounds, repositioned drugs, as well as natural products.

Porphyromonas gingivalis: where do we stand in our battle against this oral pathogen?

Studies on the stable hemiaminals and Schiff bases formation in the reaction of substituted benzaldehydes with primary 3,5-dimethyl-1,2,4-triazole 4-amine were carried out under neutral conditions. These products were investigated by IR, Raman, MS, ¹H- and (13)C-NMR spectra as well as by X-ray crystallography. The effect of reaction conditions: temperature, polarity of the solvents utilized, substrate concentration and the ortho and para benzaldehyde substituents on the yield of products was also examined.

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A Study on the Condensation Reaction of 4-Amino-3,5-dimethyl-1,2,4-triazole with Benzaldehydes: Structure and Spectroscopic Properties of Some New Stable Hemiaminals

A study on the condensation reaction of aryl substituted 4-amine-1,2,4-triazole with benzaldehydes: Structures and spectroscopic properties of schiff bases and stable hemiaminals

Robert Wróbel

Papers

A Study on the Condensation Reaction of 4-Amino-3,5-dimethyl-1,2,4-triazole with Benzaldehydes: Structure and Spectroscopic Properties of Some New Stable Hemiaminals

A study on the condensation reaction of aryl substituted 4-amine-1,2,4-triazole with benzaldehydes: Structures and spectroscopic properties of schiff bases and stable hemiaminals

Antimicrobial activity of stable hemiaminals against Porphyromonas gingivalis.

Coordination studies of nitrogen-containing aryl phosphine ligands PˆN and PˆNˆN with rhodium