Cobalt(III) complexes with Schiff base ligands derived from hydrazone, (  = ()-'-(3,5-dichloro-2-hydroxybenzylidene)-4-hydroxybenzohydrazide,  = ()-'-(3,5-dichloro-2-hydroxybenzylidene)-4-hydroxybenzohydrazide (3,5-dibromo-2-hydroxybenzylidene), and  = ()-4-hydroxy-'-(2-hydroxy-3-ethoxybenzylidene)benzohydrazide), were synthesized and characterized by elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, UV-Vis spectroscopy, and cyclic voltammetry. X-ray diffraction was used to determine the single crystal structure of the complex (). Co(III) was formed in a distorted, very regular octahedral coordination in this complex; three pyridine moieties complete this geometry. Schiff base complexes' redox behaviors are represented by irreversible (), quasi-reversible (), and quasi-reversible () voltammograms. A density functional theory (DFT)/B3LYP method was used to optimize cobalt complexes with a base set of 6-311G. Furthermore, fragments occupying the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were investigated at the same theoretical level. Quantum theory of atoms in molecules (QTAIM) computations were also done to study the coordination bonds and non-covalent interactions in the investigated structures. Hirshfeld surface analysis was used to investigate the nature and types of intermolecular exchanges in the crystal structure of the complex (). The capacity of cobalt complexes to bind to the major protease SARS-CoV-2 and the molecular targets of human angiotensin-converting enzyme-2 (ACE-2) was investigated using molecular docking. The molecular simulation methods used to assess the probable binding states of cobalt complexes revealed that all three complexes were stabilized in the active envelope of the enzyme by making distinct interactions with critical amino acid residues. Interestingly, compound () performed better with both molecular targets and the total energy of the system than the other complexes.

Amino-functionalized P(V) derivatives providing both - and -donor modes have attracted interest owing to their potential to form interesting coordination assemblies with applications such as biological drugs. Novel coordination modes of two- and four-dentate tris (pyridin-2-yl)phosphoric triamide OP[NH-Py] as ([Co{[O][NH-Py]P(O)[Ph]}(DMF)], ) and ([CuCl{[NH-Py]P(O)[N-Py]}].DMF, ) have been synthesized and structurally studied. The metal center environment is distorted octahedral for and distorted square pyramidal for . The crystal structure of a new complex of Cu with a Cu[N][Cl] environment ([CuCl(Pyrazole)], ) is also investigated. An evaluation of the inhibitory effect against the coronavirus (Main Protease [M] of SARS-CoV-2) was carried out by a molecular docking study and illustrates that these compounds have a good interaction tendency with CoV-2, where has the best binding affinity with the biological target comparable with other SARS-CoV-2 drugs. Moreover, theoretical QTAIM and natural bond orbital (NBO) calculations are used to evaluate the metal-oxygen/-nitrogen bonds suggesting that they are mainly electrostatic in nature with a slight covalent contribution. A molecular packing analysis using Hirshfeld surface (HS) analysis shows that N-H … O (in and ) and N-H … Cl (in ) hydrogen bonds are the dominant interactions that contribute to the crystal packing cohesion. The semi-empirical PIXEL method indicates that the electrostatic and repulsion energy components in the structures of and and the dispersion and electrostatic components in that of are the major contributors to the total lattice energy.

Two new mixed-ligand complexes with general formula [Cu(SB)(L')]ClO ( and ) were synthesized and characterized by different spectroscopic and analytical techniques including Fourier transform infrared (FT-IR) and UV-Vis spectroscopy and elemental analyses. The SB ligand is an unsymmetrical tridentate NN'O type Schiff base ligand that was derived from the condensation of 1,2-ethylenediamine and 5-bromo-2-hydroxy-3-nitrobenzaldehyde. The L' ligand is pyridine in () and 2,2'-dimethyl-4,4'-bithiazole () in (). Crystal structure of () was also obtained. The two complexes were used as anticancer agents against leukemia cancer cell line HL-60 and showed considerable anticancer activity. The anticancer activity of these complexes was comparable with the standard drug 5-fluorouracil (5-FU). Molecular docking and pharmacophore studies were also performed on DNA (PDB:1BNA) and leukemia inhibitor factor (LIF) (PDB:1EMR) to further investigate the anticancer and anti-COVID activity of these complexes. The molecular docking results against DNA revealed that () preferentially binds to the major groove of DNA receptor whereas () binds to the minor groove. Complex () performed better with 1EMR. The experimental and theoretical results showed good correlation. Molecular docking and pharmacophore studies were also applied to study the interactions between the synthesized complexes and SARS-CoV-2 virus receptor protein (PDB ID:6LU7). The results revealed that complex () had better interaction than (), the free ligands ( and ), and the standard drug favipiravir.

Since 2019, the infection of SARS-CoV-2 has been spreading worldwide and caused potentially lethal health problems. In view of this, the present study explores the most commodious and environmentally benign synthetic protocol for the synthesis of tetrahydrobenzo[]pyran and pyrano[2,3-]pyrimidinones as SARS-CoV-2 inhibitors via three-component cycloaddition of aromatic aldehyde, malononitrile, and dimedone/barbituric acid in water. Lemon peel from juice factory waste, namely, lemon (), sweet lemon (), and Kaffir lime or Citron (), effectually utilized to obtain WELPSA, WESLPSA, and WEKLPSA, respectively, for the synthesis of title compounds. The catalyst was characterized by scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDX). The concentration of sodium, potassium, calcium, and magnesium in the catalyst (WELPSA) was determined using atomic absorption spectrometry (AAS). The current approach manifests numerous notable advantages that include ease of preparation, handling and benignity of the catalyst, low cost, green reaction conditions, facile workup, excellent yields (93%-97%) with extreme purity, and recyclability of the catalyst. Compounds were docked on the crystal structure of SARS-CoV-2 (PDB: 6M3M). The consensus score obtained in the range 2.47-4.63 suggests that docking study was optimistic indicating the summary of all forces of interaction between ligands and the protein.

The purpose of this study was to develop a multifunctional theranostic probe for imaging (magnetic resonance imaging [MRI] and single-photon emission computed tomography [SPECT]) and therapy (photodynamic therapy). For this purpose, Tc-99m-labeled lupulone-conjugated FeO@TiO nanocomposites (Tc-DTPA-FeO@TiO-HLP and Tc-DTPA-FeO@TiO-ALP nanocomposites) were synthesized. The average diameter of the nanocomposites was 171 ± 20 nm as seen on transmission electron microscopy images. FeO@TiO nanocomposites exhibited fluorescence spectra at an emission wavelength of 314 nm. Lupulone-conjugated FeO@TiO nanocomposites were spherical-shaped with a suitable dispersion and without visible aggregation, and their radiolabeling yields were over 85%. Healthy (RWPE-1 normal human prostate epithelial cell line) and cancer prostate cell lines (PC-3 human prostate cancer cell line) were used to determine the in vitro biological behavior of the nanocomposites. The PC-3 cells treated with lupulone-conjugated FeO@TiO nanocomposites showed a lower cell viability compared with RWPE-1 cells treated with lupulone-conjugated FeO@TiO nanocomposites. Lupulone-modified FeO@TiO nanocomposites may serve in the future as a multifunctional probe for positron emission tomography (PET)/MRI, photodynamic therapy, and hyperthermia therapy of cancer.

Symmetrical bis-Schiff bases (LH ) have been synthesized by the condensation of 1,6-hexanediamine (hn) and carbonyl or dicarbonyl. One of the synthesized Schiff bases has been subjected to the molecular docking for the prediction of their potentiality against coronavirus (SARS-CoV-2). Molecular docking revealed that tested Schiff base possessed high binding affinity with the receptor protein of SARS CoV-2 compared with hydroxychloroquine (HCQ). The ADMET analysis showed that ligand is non-carcinogenic and less toxic than standard HCQ. Schiff bases acting as dibasic tetra-dentate ligands formed titanium (IV) complexes of the type [TiL(HO)Cl] or [TiL(HO)]Cl being coordinated through ONNO donor atoms. Ligands and complexes were characterized by the elemental analysis and physicochemical and spectroscopic data including FTIR, H NMR, mass spectra, UV-Visible spectra, molar conductance, and magnetic measurement. Optimized structures obtained from quantum chemical calculations supported the formation of complexes. Antibacterial, antifungal, and anti-oxidant activity assessments have been studied for synthesized ligands and complexes.

Approximately every 100 years, as witnessed in the last two centuries, we are facing an influenza pandemic, necessitating the need to combat a novel virus strain. As a result of the new coronavirus (severe acute respiratory syndrome coronavirus type 2 [SARS-CoV-2] outbreak in January 2020, many clinical studies are being carried out with the aim of combating or eradicating the disease altogether. However, so far, developing coronavirus disease 2019 (COVID-19) detection kits or vaccines has remained elusive. In this regard, the development of antiviral nanomaterials by surface engineering with enhanced specificity might prove valuable to combat this novel virus. Quantum dots (QDs) are multifaceted agents with the ability to fight against/inhibit the activity of COVID-19 virus. This article exclusively discusses the potential role of QDs as biosensors and antiviral agents for attenuation of viral infection.

In this study, FeO@TiO nanoparticles were synthesized as a new Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) hybrid imaging agent and radiolabeled with Zr. In addition, FeO nanoparticles were synthesized and radiolabeled with Zr. Df-Bz-NCS was used as bifunctional ligand. The nanoconjugates were characterized with transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. Radiolabeling yields were 100%. Breast and prostate cancer cell affinities and cytotoxicity were determined using cell culture assays. The results demonstrated that FeO@TiO nanoparticles are promising for PET/MR imaging. Finally, unlike FeO nanoparticles, FeO@TiO nanoparticles showed a fluorescence spectrum at an excitation wavelength of 250 nm and an emission wavelength of 314 nm. Therefore, in addition to bearing the magnetic properties of FeO nanoparticles, FeO@TiO nanoparticles display fluorescence emission. This provides them with photodynamic therapy potential. Therefore multimodal treatment was performed with the combination of PDT and RT by using human prostate cancer cell line (PC3). The development of Zr-Df-Bz-NCS-FeO@TiO nanoparticles as a new multifunctional PET/MRI agent with photodynamic therapy and hyperthermia therapeutic ability would be very useful.

Host-guest interactions between α-, β-, and γ-cyclodextrins and vanadocene dichloride (Cp(2)VCl(2)) have been investigated by a combination of thermogravimetric analysis, differential scanning calorimeters, PXRD and solid state and solution EPR spectroscopy. The solid state results demonstrated that only β- and γ-cyclodextrins form 1:1 inclusion complexes, while α-cyclodextrin does not form an inclusion complex with Cp(2)VCl(2). The β- and γ-CD-Cp(2)VCl(2) inclusion complexes exhibited anisotropic electron-(51)V (I = 7/2) hyperfine coupling constants whereas the α-CD- Cp(2)VCl(2) system showed only an asymmetric peak with no anisotropic hyperfine constant. On the other hand, solution EPR spectroscopy showed that α-CD may be involved in weak host-guest interactions in equilibrium with free vanadocene species.