Synthesis, Structural Characterization and Antimicrobial Activity of Cu(II) and Fe(III) Complexes Incorporating Azo-Azomethine Ligand.

We are reporting a novel azo-azomethine ligand, HL and its complexes with Cu(II) and Fe(III) ions. The ligand and its complexes are characterized by various physico-chemical techniques using C,H,N analyses, FT-IR, ¹H-NMR, ESI-MS and UV-Vis studies. TGA analyses reveal complexes are sufficiently stable and undergo two-step degradation processes. The redox behavior of the complexes was evaluated by cyclic voltammetry. Furthermore, the ligand and its complexes were tested for antimicrobial activity against bacterial and fungal strains by determining inhibition zone, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The complexes showed moderate antimicrobial activity when tested against Gram +ve and Gram -ve bacterial strains. To obtain insights into the structure of ligand, DFT studies are recorded. The results obtained are quite close to the experimental results. In addition, the energy gap, chemical hardness, softness, electronegativity, electrophilic index and chemical potential were calculated using HOMO, LUMO energy value of ligand.

Novel nickel(II), palladium(II), and platinum(II) complexes having a pyrrolyl-iminophosphine (PNN) pincer: Synthesis, crystal structures, and cytotoxic activity.

A pyrrolyl-iminophosphine (PNNH) which would act as a potential terdentate ligand has been prepared by Schiff base reaction. Complexes [M(PNN)X] (M = Ni; X = Cl (1), Pd; X = Cl (2), Br (3), I (4), M = Pt; X = Cl (5)) were prepared. The title complexes were characterized by various spectroscopic (IR, 1H, 13C, and 31P NMR) and elemental analyses. The molecular structures of 1, 2, and 5 have been established by single-crystal X-ray crystallography, demonstrating a distorted square planar geometry comprising two 5-membered metallacyclic rings. Complexes 1 and 2 were found to crystallize in the orthorhombic while complex 5 crystallizes in the monoclinic. Cytotoxicities of the complexes along with PNNH were evaluated against A549 (lung), SK-OV-3 (ovarian), SM-MEL-2 (skin), and HCT15 (colon) human cancer cell lines by sulforhodamine B assay. Notably, the palladium(II) complex (2) shows the highest activity. Apoptosis activity along with the caspase inhibitor Z-VAD (Z-Val-Ala-Asp-fluoromethyl ketone) assay of 2 and 5 against A549 and HCT15 cancer cell lines were investigated to learn a mechanistic pathway for the observed cytotoxicity, practically eliminating an apoptotic cell-death route. Complexes 2 and 5 were studied to DNA cleavage assay and molecular docking simulation. The DNA (pcDNA3.0) cleavage experiment evaluates complex 5 interacting with DNA, more effectively, in comparison to complex 2. Molecular docking simulation of 2 and 5 toward DNA and GRP78 (glucose-regulated protein 78) was performed to predict binding sites of ligand-receptors and a plausible mechanistic aspect of metallodrug-action.

Synthesis, Antibacterial Activity and Molecular Docking of Phospholidinones in Stigmastane Series.

INTRODUCTION: Steroid compounds are widely distributed in nature throughout scientific history. Living organisms such as animals and vegetables have steroids that show a significant effect on their vital activities. Sterols are key components of all eukaryotic cell membranes. METHODS: Steroidal compounds; 3ß-oxo-[1',3',2'-oxathiaphos-phalidine-2'-one] stigmast-5-ene and 3ß- oxo[1`,3`,2`-dioxaphosphalidine-2`-one]-stigmast-5-ene were successfully prepared using easily accessible 3ß-hydroxy stigmast-5-ene with phosphorous oxychloride (POCl3), 2- mercaptoethanol/ethylene glycol and triethylamine (Et3N) in dry diethyl ether. Products were obtained in semi-solid state and characterized using physicochemical techniques. RESULTS: The results of the bioassay showed that the synthesized compound containing the sulfur atom had antibacterial activity. Molecular docking was also done in order to show in silico antibacterial activity and to make out the probable binding mode of compound with the amino acid residues of protein. CONCLUSION: The results of the docking study showed that synthesized compound 2 had minimal binding energy with substantial affinity for the active site.

DFT/TD-DFT calculations, spectroscopic characterizations (FTIR, NMR, UV-vis), molecular docking and enzyme inhibition study of 7-benzoyloxycoumarin.

The quantum chemical study, spectroscopic characterization and biological activity of the pharmaceutically active 7-benzoyloxycoumarin (2) molecule have been presented. Potential energy surface (PES) scanning has been performed to search for the most stable molecular geometry of the present compound. The stable geometry in the ground state, IR, UV-Vis absorption and NMR (13C, 1H) spectra of the title compound were theoretically obtained and compared with the experimental one. Various theoretical molecular parameters like molecular energy, atomic charges, dipole moment, thermodynamic parameters, donor-acceptor natural bond orbital (NBO) hyperconjugative interaction energies, frontier molecular orbitals energies, HOMO-LUMO gap, molecular electrostatic potential, chemical reactivity descriptors, molecular polarizability and non-linear optical (NLO) properties are presented. Moreover, the 3D Hirshfeld surfaces and the associated 2D fingerprint plots have been explored. The percentages of various non-covalent interactions are studied and pictorialized by fingerprint plots of Hirshfeld surface. 7-Benzoyloxycoumarin has shown promising inhibitory activity against butrylcholinesterase (BuChE) as compared to the reference drug, galantamine. Molecular docking is carried to introduce compound into the X-ray crystal structures of butrylcholinesterase at the active site to find out the probable binding mode. The results of molecular docking indicated that 7-benzoyloxy derivative of coumarin may show enzyme inhibitor activity.

Synthesis and Characterization of [Mn(III)(6)(N-formylsalicylhydrazidate)(6)(MeOH)(6)]: A New Type of Macrocyclic Hexanuclear Manganese Cluster.

The macrocyclic hexanuclear metal cluster, [Mn(III)(6)(fshz)(6)S(6)], 1 (S = MeOH), was prepared using a trianionic pentadentate ligand, N-formylsalicylhydrazidate (fshz(3)(-)). Due to the meridional coordination of the ligand to the metal ion, the ligand is not only bridging the ring metal ions using a hydrazide N-N group but also enforcing the stereochemistry of the metal ions as a propeller configuration. The alternations of the chiralities of the metal centers expand the cyclic ring system of complex 1 to the 24-membered ring system. The neutral hexanuclear manganese complex with noncrystallographic pseudo-C(3)(i)() symmetry is in the crystallographic inversion center. The disc-shaped hexanuclear cluster is 1.8 nm in diameter and 0.8 nm in thickness and has a vacant cavity in the center of the cluster. Three solvent molecules coordinated at the metal centers with Lambda configuration are in one face of the cluster, and the remaining three solvent molecules coordinated at the other metal centers with Delta configuration are in the other face of the cluster. The two faces of the cluster have opposite chiralities to each other. The crystal packing structure of complex 1 shows that the disc-shaped hexanuclear clusters are aligned approximately along the crystallographic a axis. The cavities of the clusters in the crystal structure are also aligned, and one-dimensional channels are formed. The solution integrity of the cluster was addressed using solution mass spectrometry, paramagnetically shifted (1)H NMR spectroscopy, and UV-visible spectroscopy. Crystallographic data for 1: triclinic, P&onemacr;, a = 10.0237(9) Å, b = 15.096(1) Å, c = 15.617(1) Å, alpha = 112.142(5) degrees, beta = 106.615(5) degrees, gamma = 99.958(7) degrees, V = 1989.8(3) Å(3), Z = 2, D(calcd) = 1.510 g cm(-)(1), R1 = 0.0502 and wR2 = 0.1424 for 4249 reflections with I > 2sigma(I), GOF = 1.065.