Effect of anodic pH microenvironment on microbial fuel cell (MFC) performance in concurrence with aerated and ferricyanide catholytes

The performance of dual chambered microbial fuel cell (MFC, Nafion 117, non-catalyzed graphite electrodes) in concurrence with anodic pH microenvironment was evaluated based on bioelectricity generation and wastewater treatment efficiency. Experiments were carried out at different anodic pH microenvironments (acidophilic (6), neutral (7) and alkaline (8)) using both aerated and ferricyanide catholytes with mixed consortia as anodic biocatalyst employing chemical wastewater. Acidophilic pH in anodic chamber showed effective performance with respect to power output compared to the corresponding neutral and alkaline operations. However, substrate degradation was observed to be higher at neutral condition followed by alkaline and acidophilic operations. Ferricyanide as catholyte showed positive influence on the power output parameters compared to aerated catholyte. Nature of the catholyte did not show any visible influence on the wastewater treatment efficiency.     

Synthesis of 8-heteroatom-substituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene dyes (BODIPY)

Thioketones, bis-(5-R-1H-pyrrol-2-yl)-methanethiones (R=H, Me, Et), 4 react with methyl iodide or isopropyl triflate to give the pyrrolium salts, which are treated with tertiary amine and boron trifluoride to produce the 8-(thiomethyl/thioisopropyl) 4,4-difluoro-3,5-di-R-4-bora-3a,4a-diaza-s-indacenes 6a-6c and 8a-8c. The reaction of the methyl thioether group of 6a and 6b with aniline gives the substitution products whose structure corresponds to formula 10. The structures of the thioethers 6a-6c and compound 10a were determined by X-ray diffraction. The thiomethyl groups in 6a-6c are close to be coplanar to the flat ring system, the strain due to the interaction of methyl with the hydrogen at C1 is released by shifting of the sulfur atom away from carbon C1 and opening of the angle C8-S-methyl. This coplanarity of the thiomethyl group with ring system agrees with the preference of the syn conformation of methyl vinyl thioether. In the structures of the aniline compound 10a the length of the nitrogen to C8 is close to that of NC double bond. Thioethers 6a-6c show high wavelength absorption at 523-530 nm and fluorescence with a Stokes shift of 12-24 nm and with a quantum yield of 0.15-0.37. In contrast the aniline substituted compounds 10a and 10b showed absorption at 410 and 430 nm, respectively, with no fluorescence. According to their spectral properties they are better described by structure 10 than 7.     

Evaluation of the Potential of Cobalamin Derivatives Bearing Ru(II) Polypyridyl Complexes as Photosensitizers for Photodynamic Therapy

The current photosensitizers (PSs) for photodynamic therapy (PDT) lack selectivity for cancer cells. To tackle this drawback, in view of selective cancer delivery, we envisioned conjugating two ruthenium polypyridyl complexes to vitamin B₁₂ (Cobalamin, Cbl) to take advantage of the solubility and active uptake of the latter. Ultimately, our results showed that the transcobalamin pathway is unlikely involved for the delivery of these ruthenium‐based PDT PSs, emphasizing the difficulty in successfully delivering metal complexes to cancer cells.     

Efficient and Convenient Polyethylene Glycol (PEG)‐Mediated Synthesis of Spiro‐oxindoles

Polyethylene glycol (PEG) has been reported as an efficient and convenient medium for the three‐component synthesis for spiro‐oxindole.     

Two new macrocyclic diaryl ether heptanoids from Boswellia ovalifoliolata

The stems of Boswellia ovalifoliolata BAL. & HENRY (Burseraceae) afforded two new macrocyclic diaryl ether heptanoids, ovalifoliolatin A (1) and B (2) together with three known compounds; acerogenin C (3), 3 alpha-hydroxyurs-12-ene (4), and sitost-4-en-3-one (5). The structures were established by means of spectroscopic analysis and compounds 1, 3-5 were evaluated for their antibacterial activity.     

Mixed ligand complexes of palladium(II) and platinum(II) with methionine and 2,4-disubstituted pyrimidines

Summary Mixed ligand complexes ofcis-[M(MetH)Cl₂] (M=Pd²⁺ and Pt²⁺; MetH=methionine) with 2,4-disubstituted pyrimidines were prepared and characterised. Thecis-[Pd(MetH)Cl₂] complex reacted with cytosine (2-hydroxy-4-aminopyrimidine), isocytosine (2-amino-4-hydroxypyrimidine) and thiocytosine (2-thio-4-amino-pyrimidine) to form ternary complexes.cis-[Pt(MetH)Cl₂] however reacted with cytosine, uracil (2,4-pyrimidine dione or 2,4-dihydroxypyrimidine) to yield the corresponding mixed ligand complexes. The primary ligand, methionine, binds to the metal ion through sulphur and amino nitrogenvia a six membered chelate ring. The secondary ligands (substituted pyrimidines) bind to the Pd²⁺ or Pt²⁺ metal ion through the ring nitrogen (N₃), as monodentate ligand. Thiocytosine however acts as a bidentate ligand, coordinating to the metal ion through-SH and ring nitrogen (N₃). All complexes are 11 electrolytes, except the thiocytosine complex, which is a 12 electrolyte.     

Ultrathin multilayer of Fe and Ge: structure and magnetic properties

Metal-semiconductor multilayers are interesting, artificial structures as prospective candidates for spin injection devices. A Fe–Ge multilayer sample with very thin individual layers (few crystallographic planes) has been deposited by sputtering on Si[1 0 0] substrate. We have characterized the structure of this multilayer sample using X-ray diffraction, X-ray reflectometry and neutron reflectometry. The magnetic moment density in the ferromagnetic Fe layer has been obtained by polarized neutron reflectometry and the bulk magnetic behavior of the thin film by SQUID magnetometer measurements. We found that the film is a soft ferromagnet at room temperature with a substantially reduced magnetic moment of the Fe atoms.     

Furano compounds—part XIII

The Synthesis of 3, 5′-dimethyl- and 3,4′-dimethyl-furaro (2′, 3′:1, 2)?6, 7-benzoxanthones (III and IV) is described.