POCl3 mediated one-pot deoxygenative aromatization and electrophilic chlorination of dihydroxy-2-methyl-4-oxo-indeno[1,2-b]pyrroles.

A class of indenopyrroles is presented by the treatment of known dihydroxy-2-methyl-4-oxoindeno[1,2-b]pyrroles with phosphorus oxychloride (POCl3). The elimination of vicinal hydroxyl groups at the 3a and 8b positions, formation of a π bond, and electrophilic chlorination of the methyl group attached to C2 resulted in the fused aromatic pyrrole structures. Benzylic substitution of various nucleophiles such as H2O, EtOH, and NaN3 with a chlorine atom gave diverse 4-oxoindeno[1,2-b]pyrrole derivatives in 58 to 93% yields. The reaction was investigated in different aprotic solvents, and the highest reaction yield was obtained in DMF. The structures of the products were confirmed by spectroscopic methods, elemental analysis, and X-ray crystallography.

A novel water-soluble thiosemicarbazone Schiff base ligand and its complexes as potential anticancer agents and cellular fluorescence imaging.

A novel fluorescent ligand (H2LCl⋅1.5CH3OH, 1) was synthesized and metal complexes of 1 with Mn(II), Fe(III), Ni(II), Cu(II), and Zn(II) were obtained as Mn(HL)2Cl2 (2), Fe(HL)2Cl3⋅3H2O (3), Ni(L)(HL)Cl⋅8H2O (4), Cu(HL)Cl2⋅4H2O (5), Zn(H2L)Cl3 (6), respectively. These compounds were identified by spectroscopic methods, elemental analysis, molar conductivity, and single-crystal X-ray crystallography. According to the crystal structure of 4 nickel (II), center is surrounded by two ligands in a distorted octahedral geometry. The ligand and its complexes are soluble in water and have excellent stability. In vitro anti-proliferative activity of these compounds was evaluated against human breast adenocarcinoma (MCF-7) and human lipo-sarcoma (SW-872) as cancer cells and human fibroblasts (HFF-2) as normal cells by MTT assay. Interestingly, complex 5 exhibited excellent activity against both cancer cells with low IC50 value 22.18 ± 0.35 µg/mL (35.66 ± 0.56 µM) for SW-872 and 79.41 ± 3.54 µg/mL (127.6 ± 5.69 µM) for MCF-7 among the compounds and in comparison with paclitaxel (PTX) which acts finely. Morphological changes were evaluated by flow cytometry that revealed apoptosis is the main cause of cell death. Likewise, cell cycle studies indicated the cell cycle arrest in the G1 and S phases for complex 5 against MCF-7 and SW-872 cancer cells, while complex 6 could arrest the MCF-7 and SW-872 cells in G2 and G1 phases, respectively. All of the compounds are fluorescent which enabled us to monitor the uptake and intracellular distribution in living human cancer cells by fluorescence microscopy.

Five new complexes with deferiprone and N,N-donor ligands: evaluation of cytotoxicity against breast cancer MCF-7 cell line and HSA-binding determination.

In this study, five new complexes containing deferiprone (dfp) and N,N-donor ligands [bipyridine (bpy), 1,10-phenanthroline (phen) and ethylenediamine (en)] were synthesized: [Fe(dfp)2(bpy)](PF6) (1), [Fe(dfp)2(phen)](PF6) (2), [Cu2(dfp)2(bpy)2](PF6)2 (3), [Ga(dfp)2(bpy)](PF6) (4), and [Fe(dfp)2(en)](PF6) (5). Characterization of these complexes was carried out through elemental analysis and FT-IR, and single-crystal X-ray crystallography was used to determine their structures. Whilst the polyhedron has a distorted octahedral geometry in 1, 2, 4, and 5, it adopts a distorted square-pyramidal geometry in 3. Interaction of these compounds with human serum albumin (HSA) has been investigated through electronic absorption and fluorescence titration techniques. Emission quenching was performed separately for each complex at three different temperatures and thermodynamic parameters were calculated using binding constants to better understand the power of different binding forces with the HSA. Results demonstrated that compounds interact strongly with the HSA with a static quenching mechanism. Our evaluation of the cytotoxicity of complexes against the breast cancer MCF-7 cell line showed that complex 2 presents a better cytotoxicity than the standard cis-Pt. Finally, using the AutoDock 4.2 program, simulations to analyze the mechanism of complex-HSA interactions and their binding mode were carried out. Results showed that the best binding mode is located in subdomain IB for 1, 2, and 4, in I/II for 3, and in IA/IIA for 5. Communicated by Ramaswamy H. Sarma.

A new ß-CdTeO3 polymorph with a structure related to α-CdTeO3.

A new ß-CdTeO3 polymorph was obtained by hydrothermal synthesis and its structure was solved ab initio from powder X-ray diffraction data. It appears that the structure of ß-CdTeO3 (Pnma, Z = 16, a = 7.45850(3) Å, b = 14.52185(6) Å, c = 11.04584(5) Å) is closely related to that of α-CdTeO3 (P21/c, Z = 8, a = 7.790(1) Å, b = 11.253(2) Å, c = 7.418(1) Å, ß = 113.5(1)°) previously reported. The 3D framework of ß-CdTeO3 is built of both [CdO6] distorted octahedra and [CdO7] mono-capped trigonal prisms and three different tellurium polyhedra: trigonal pyramids [TeIVO3E] and trigonal bipyramids [TeIVO4E] and [TeIVO3+1E] (E denotes the lone pair of TeIV). The electronic structure calculations based on density functional theory methods show that at the ground state α-CdTeO3 is slightly more stable than ß-CdTeO3 with an energy difference of 4.64 kJ mol-1. The band structures confirm the results of optical UV-Vis spectroscopy measurements: both polymorphs are wide bandgap semiconductors with Eg = 3.55 eV for ß-CdTeO3 and Eg = 3.91 eV for α-CdTeO3. The DOS calculations for both polymorphs enable one to understand that the presence of the [TeIVO4E] polyhedra in ß-CdTeO3 (absent in α-CdTeO3) lowers its bandgap. Above 540 °C ß-CdTeO3 transforms into α-CdTeO3 in a first order phase transition.

Hydrothermal Synthesis and Dehydration of CaTeO3(H2O): An Original Route to Generate New CaTeO3 Polymorphs.

CaTeO3(H2O) was obtained from microwave-assisted hydrothermal synthesis as a polycrystalline sample material. The dehydration reaction was followed by thermal analysis (thermogravimetric/differential scanning calorimetry) and temperature-dependent powder X-ray diffraction and leads to a new δ-CaTeO3 polymorph. The crystal structures of CaTeO3(H2O) and δ-CaTeO3 were solved ab initio from PXRD data. CaTeO3(H2O) is non-centrosymmetric: P21cn; Z = 8; a = 14.785 49(4) Å; b = 6.791 94(3) Å; c = 8.062 62(3) Å. This layered structure is related to the ones of MTeO3(H2O) (M = Sr, Ba) with layers built of edge-sharing [CaO6(H2O)] polyhedra and are capped of each side by [Te(IV)O3E] units. Adjacent layers are stacked along the a-axis and are held together by H-bonds via the water molecules. The dehydration reaction starts above 120 °C. The transformation of CaTeO3(H2O) into δ-CaTeO3 (P21ca; Z = 8; a = 13.3647(6) Å; b = 6.5330(3) Å; c = 8.1896(3) Å) results from topotactic process with layer condensation along the a-axis and the 1/2b⃗ translation of intermediate layers. Thus, δ-CaTeO3 stays non-centrosymmetric. The characteristic layers of CaTeO3(H2O) are also maintained in δ-CaTeO3 but held together via van der Waals bonds instead of H-bonds through water molecules. Electron localization function and dipole moment calculations were also performed. For both structures and over each unit cell, the dipole moments are aligned antiparallel with net dipole moments of 3.94 and 0.47 D for CaTeO3(H2O) and δ-CaTeO3, respectively. The temperature-resolved second harmonic generation (TR-SHG) measurements, between 30 and 400 °C, show the decreasing of the SHG intensity response from 0.39 to 0.06 × quartz for CaTeO3(H2O) and δ-CaTeO3, respectively.