Synthesis, properties, antitumor and antibacterial activity of new Pt(II) and Pd(II) complexes with 2,2'-dithiobis(benzothiazole) ligand

Phenylbenzothiazole-Based Platinum(II) and Diplatinum(II) and (III) Complexes with Pyrazolate Groups: Optical Properties and Photocatalysis

Based on 2-phenylbenzothiazole (pbt) and 2-(4-dimethylaminophenyl)benzothiazole (Me2N-pbt), mononuclear [Pt(pbt)(R'2-pzH)2]PF6 (R'2-pzH = pzH 1a, 3,5-Me2pzH 1b, 3,5-iPr2pzH 1c) and diplatinum (PtII-PtII) [Pt(pbt)(μ-R'2pz)]2 (R'2-pz = pz 2a, 3,5-Me2pz 2b, 3,5-iPr2pz 2c) and [Pt(Me2N-pbt)(μ-pz)]2 (3a) complexes have been prepared. In the presence of sunlight, 2a and 3a evolve, in CHCl3 solution, to form the PtIII-PtIII complexes [Pt(R-pbt)(μ-pz)Cl]2 (R = H 4a, NMe2 5a). Experimental and computational studies reveal the negligible influence of the pyrazole or pyrazolate ligands on the optical properties of 1a-c and 2a,b, which exhibit a typical 3IL/3MLCT emission, whereas in 2c the emission has some 3MMLCT contribution. 3a displays unusual dual, fluorescence (1ILCT or 1MLCT/1LC), and phosphorescence (3ILCT) emissions depending on the excitation wavelength. The phosphorescence is lost in aerated solutions due to sensitization of 3O2 and formation of 1O2, whose determined quantum yield is also wavelength dependent. The phosphorescence can be reversibly photoinduced (365 nm, ∼ 15 min) in oxygenated THF and DMSO solutions. In 4a and 5a, the lowest electronic transitions (S1-S3) have mixed characters (LMMCT/LXCT/L'XCT 4a and LMMCT/LXCT/ILCT 5a) and they are weakly emissive in rigid media. The 1O2 generation property of complex 3a is successfully used for the photooxidation of p-bromothioanisol showing its potential application toward photocatalysis.

Biomedical applications of selective metal complexes of indole, benzimidazole, benzothiazole and benzoxazole: A review (From 2015 to 2022)

Indole, benzoxazole benzothiazole and benzimidazole are excellent classes of organic heterocyclic compounds. These compounds show significant application in pharmacy, industries, dyes, medicine, polymers and food packages. These compounds also form metal complexes with copper, zinc, cadmium, nickel, cobalt, platinum, gold, palladium chromium, silver, iron, and other metals that have shown to be significant applications. Recently, researchers have attracted enormous attention toward heterocyclic compounds such as indole, benzimidazole, benzothiazole, benzoxazole, and their complexes due to their excellent medicinal applications such as anti-ulcerogenic, anti-cancer, antihypertensive, antifungal, anti-inflammatory, antitubercular, antiparasitic, anti-obesity, antimalarial, antiglycation, antiviral potency, antineuropathic, analgesic antioxidant, antihistaminic, and antibacterial potentials. In this article, we summarize the medicinal applications of these compounds as well as their metal complexes. We hope this article will help researchers in designing and synthesizing novel and potent compounds with significant applications in various fields.

Natural Pigments Production and Their Application in Food, Health and Other Industries

In addition to fulfilling their function of giving color, many natural pigments are known as interesting bioactive compounds with potential health benefits. These compounds have various applications. In recent times, in the food industry, there has been a spread of natural pigment application in many fields, such as pharmacology and toxicology, in the textile and printing industry and in the dairy and fish industry, with almost all major natural pigment classes being used in at least one sector of the food industry. In this scenario, the cost-effective benefits for the industry will be welcome, but they will be obscured by the benefits for people. Obtaining easily usable, non-toxic, eco-sustainable, cheap and biodegradable pigments represents the future in which researchers should invest.

Insights into Two Novel Orthopalladated Chromophores with Antimicrobial Activity against Escherichia coli

Advanced chromophoric tools, besides being biologically active, need to meet the expectations of the technological demands including stability, colour retention, and proper solubility for their target. Many coordination compounds of conjugated ligands are antibacterial dyes, able to combine a strong dyeing performance with a useful biological activity. Specifically, palladium (II) complexes of Schiff base ligands are known for their relevant activity against common bacteria. In this article, we report the synthesis and comprehensive experimental and theoretical characterization of two novel Pd(II) chromophore complexes obtained from a cyclopalladated Schiff base as two different chelating azo dyes. The antibacterial response of these two novel complexes was tested against the ubiquitous Escherichia coli bacterium in an aqueous medium and revealed a noteworthy antimicrobial activity, higher than when compared with their uncoordinated biologically active ligands.

Palladium(ii) and platinum(ii) complexes with ONN donor pincer ligand: synthesis, characterization and in vitro cytotoxicity study

New Pd(ii) and Pt(ii) complexes with ONN donor pincer ligand are synthesized. Antiproliferative activity of the complexes is explored towards HCT116, HepG2, MCF-7 and A549 cell lines.

Antimicrobial activity of mono- and polynuclear platinum and palladium complexes

Introduction. Infectious diseases remain a serious threat to humanity worldwide as bacterial pathogens grow more diverse. Bacteria, fungi, and parasites develop resistance to clinically approved antimicrobials, which reduces the efficacy of available drugs and treatment measures. As a result, there is an ever growing demand for new highly effective pharmaceuticals. This review describes mono- and polynuclear platinum and palladium complexes with antimicrobial properties. We compared several groups of antibacterial agents: antibiotics, antioxidant biologically active substances, antimicrobial nanoparticles, nanocomposite materials, biopolymers, micellar systems, and plant extracts. Study objects and methods. The review covered relevant articles published in Web of Science, Scopus, and Russian Science Citation Index for the last decade. The list of descriptors included such terms as mononuclear and binuclear complexes of platinum, palladium, and antimicrobial activity. Results and discussion. Chelates of platinum, palladium, silver, iridium, rhodium, ruthenium, cobalt, and nickel are popular therapeutic agents. Their antimicrobial activity against pathogenic microorganisms can be enhanced by increasing their bioavailability. Metalbased drugs facilitate the transport of organic ligands towards the bacterial cell. The nature of the ligand and its coordination change the thermodynamic stability, kinetic lability, and lipophilic properties of the complex, as well as the reactivity of the central atom. Polynuclear platinum and palladium complexes contain two or more bound metal (coordinate) centers. Covalent bonding with bacterial DNA enables them to form a type of DNA adducts, which is completely different from that of mononuclear complexes. Conclusion. Metal-based drugs with functional monodentate ligands exhibit a greater antimicrobial effect compared to free ligands. Poly- and heteronuclear complexes can increase the number of active centers that block the action of bacterial cells. When combined with other antibacterial agents, they provide a synergistic effect, which makes them a promising subject of further research.

Mononuclear Perfluoroalkyl-Heterocyclic Complexes of Pd(II): Synthesis, Structural Characterization and Antimicrobial Activity

Two mononuclear Pd(II) complexes [PdCl₂(pfptp)] (1) and [PdCl₂(pfhtp)] (2), with ligands 2-(3-perfluoropropyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfptp) and 2-(3-perfluoroheptyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfhtp), were synthesized and structurally characterized. The two complexes showed a bidentate coordination of the ligand occurring through N atom of pyridine ring and N4 atom of 1,2,4-triazole. Both complexes showed antimicrobial activity when tested against both Gram-negative and Gram-positive bacterial strains.

Synthesis, crystal structures, DFT studies, antibacterial assays and interaction assessments with biomolecules of new platinum(ii) complexes with adamantane derivatives

Synthesis, crystal structures and antibacterial activities of new Pt(ii) complexes with adamantane derivatives are presented in this article.

Essential Oil Composition of Alluaudia procera and in Vitro Biological Activity on Two Drug-Resistant Models

Drug resistance is a major obstacle in antibiotic and antitumor chemotherapy. In response to the necessity to find new therapeutic strategies, plant secondary metabolites including essential oils (EOs) may represent one of the best sources. EOs in plants act as constitutive defenses against biotic and abiotic stress, and they play an important role in the pharmacology for their low toxicity, good pharmacokinetic and multitarget activity. In this context, natural products such as EOs are one of the most important sources of drugs used in pharmaceutical therapeutics. The aim of this paper was to identify the chemical composition of the essential oil of Alluaudia procera leaves, obtained by hydrodistillation and analysed by gas chromatography-mass spectrometry, and to verify its biological activities on acute myeloid leukemia cancer cell HL60 and its multidrugresistant variant HL60R and the Gram-positive Staphylococcus aureus exhibiting multi-antibiotic resistance. We speculate that cytotoxic and antibiotic effects observed in the tested resistant models may be due to the coordinate activities of forty compounds detected or to the C₁₆ macrocyclic lactones which are the major ones (30%). Our data confirm the possibility of using EOs as therapeutic strategies in resistant models is due to the heterogeneous composition of the oils themselves.

Methanol-dispersed of ternary Fe3O4@γ-APS/graphene oxide-based nanohybrid for novel removal of benzotriazole from aqueous solution

A novel nanohybrid: Fe₃O₄ coated with γ-APS polymer deposited on graphene oxide (F@γ-A/G), to remove an emergent heterocyclic contaminant benzotriazole (BTA) from solution. F@γ-A/G was synthesized in methanol-dispersion via aminosilanization under ultra-sonication. We newly found that F@γ-A/G crystallite lattice has a 2D triangular-network intersection with angle of 60° in three types of d₃₁₁, d₂₂₀ and d₁₁₁ planes with different interplanar spacings. Textural characteristics did not affect BTA adsorption, which was desired at high temperature (40 °C), neutral solution (pH = 6) and controlled by endothermic process. Considering the maximum BTA adsorption capacity of 312.5 mg/g, which was much higher than previously reported adsorbents, the plausible mechanism was attributed to hydrophobic, electrostatic and π-π interaction. Effects of pH and temperature are significant on BTA adsorption to F@γ-A/G. Methanol was the best solvent for multiple cycle regeneration with only 2% loss of BTA removal efficiency even after five cycles of F@γ-A/G.

Synthesis and antibacterial activity of iron-hexacyanocobaltate nanoparticles

This paper deals with the synthesis and characterization of iron-hexacyanocobaltate (FeHCC) and its antibacterial properties. The nanoparticles were prepared by a facile co-precipitation technique. Crystal structure, particle morphology, and elemental composition were determined using X-ray Powder Diffraction, X-ray fluorescence spectroscopy, Transmission Electron Microscopy (TEM), and Infrared Spectroscopy (IR). The antibacterial activity of the FeHCC nanoparticles was tested against Escherichia coli and Staphylococcus aureus as models for Gram-negative and Gram-positive bacteria, respectively, by bacterial counting method and microscopic visualization (TEM, FEG-SEM, and fluorescence microscopy). The results showed that the FeHCC nanoparticles bind to the bacterial cells, inhibit bacterial growth in a dose- and time-dependent manner, inducing a loss of the membrane potential, the production of reactive oxygen species and the release of macromolecules (nucleic acids and proteins) in the extracellular environment. To the best of our knowledge, this is the first study reporting the antimicrobial effects of metal-hexacyanometallates suggesting practical uses of these materials in different areas, such as self-cleaning surfaces or food packaging.

A water-soluble near-infrared fluorescent probe for specific Pd2+ detection

Palladium (Pd) is widely used in chemistry, biology, environmental science etc., and Pd²⁺ is the most plenitudinous oxidation state of the Pd that can exist under physiological conditions or in living cells, which could have adverse effects on both our health and environment. Thus, it is of great significance to monitor the changes of Pd²⁺. Hence, a novel near-infrared fluorescent probe M-PD has been developed for selective detection of Pd²⁺ based on naphthofluorescein in this work. The result demonstrated that M-PD exhibited favorable properties for sensing Pd²⁺ such as excellent water solubility, high selectivity and sensitivity. And the limit of detection was estimated as 10.8 nM, much lower than the threshold in drugs (5-10 ppm) specified by European Directorate for the Quality Control of Medicines. More importantly, detection and recovery experiments of Pd²⁺ in aspirin aqoeous solution and soil are satisfactory. In addition, M-PD has also been successfully used for near-infrared fluorescence imaging of Pd²⁺ in living cells, indicating that the probe has better feasibility and application potential in the determination of Pd²⁺.

Synthesis, structure and in vitro cytotoxicity of platinum(II) complexes containing eugenol and a quinolin-8-ol-derived chelator

The synthesis of potassium (η2-4-allyl-2-methoxyphenol)trichloridoplatinate(II), K[PtCl3(C10H12O2)], (1), starting from Zeise's salt and Ocimum sanctum L. oil has been optimized. Starting from (1), three new platinum(II) complexes, namely (η2-4-allyl-2-methoxyphenol)chlorido(2-methylquinolin-8-olato-κ2 N,O)platinum(II), (2), (η2-4-allyl-2-methoxyphenol)chlorido(5-nitroquinolin-8-olato-κ2 N,O)platinum(II), (3), and (η2-4-allyl-2-methoxyphenol)chlorido(5,7-dichloroquinolin-8-olato-κ2 N,O)platinum(II), [Pt(C9H4Cl2NO)Cl(C10H12O2)], (4), containing eugenol and a quinolin-8-ol derivative (R-OQ), have been synthesized and characterized by elemental analyses, MS, IR, 1H NMR and NOESY spectra. For (1) and (4), single-crystal X-ray diffraction studies were also carried out. Complexes (2)–(4) show good inhibiting abilities on three human cancer cell lines, i.e. KB, Hep-G2 and LU, with IC50 values of 1.42–17.8 µM. Complex (3) gives an impressively high activity against KB, Hep-G2, LU and MCF-7, with IC50 values of 1.42–4.91 µM, which are much lower than those of cisplatin and some other platinum(II) complexes.