Remote‐Controlled Release of Singlet Oxygen by the Plasmonic Heating of Endoperoxide‐Modified Gold Nanorods: Towards a Paradigm Change in Photodynamic Therapy

The photodynamic therapy of cancer is contingent upon the sustained generation of singlet oxygen in the tumor region. However, tumors of the most metastatic cancer types develop a region of severe hypoxia, which puts them beyond the reach of most therapeutic protocols. More troublesome, photodynamic action generates acute hypoxia as the process itself diminishes cellular oxygen reserves, which makes it a self‐limiting method. Herein, we describe a new concept that could eventually lead to a change in the 100 year old paradigm of photodynamic therapy and potentially offer solutions to some of the lingering problems. When gold nanorods with tethered endoperoxides are irradiated at 808 nm, the endoperoxides undergo thermal cycloreversion, resulting in the generation of singlet oxygen. We demonstrate that the amount of singlet oxygen produced in this way is sufficient for triggering apoptosis in cell cultures.     

Condensation of Indoline with Some 1,2‐ and 1,3‐Diketones

Bismuth nitrate catalyzed condensation reactions of indoline with 1,2‐ and 1,3‐diketones were investigated and were reported to proceed via different reaction pathways with the involvement of one or two of the carbonyl groups. While the reaction of indoline with cyclohexane‐1,3‐dione ( 4 ) gave solely condensation product, the reaction between the acetylacetone ( 5 ) and indoline provided N‐acetyl indoline as single products on retro‐aldol process. In contrast to 1,3‐diketones, the reaction with benzil ( 17 ) was performed under difficult conditions and proceeded to give secondary products.     

Mono- and dinuclear Pd(II) complexes of different salicylaldimine ligands as catalysts of transfer hydrogenation of nitrobenzene with cyclohexene and Suzuki-Miyaura coupling reactions

In this study, the synthesis, spectroscopic, catalytic, and electrochemical properties of salicylaldimine Schiff-base ligands (L_n) and their dinuclear Pd(II) complexes for L₁ and L₂ ligands with mononuclear Pd(II) complexes for L₃ and L₄ ligands were investigated. The ligands and their mono- or dinuclear Pd(II) complexes were characterized by FT-IR, UV-Vis, ¹H NMR and elemental analysis, as well as through magnetic susceptibility and spectroelectrochemical techniques. The catalytic studies showed that the introduction of tert butyl groups on the salicyl ring of the molecules increased the catalytic activity towards hydrogenation of nitrobenzene and cyclohexene in DMF at 25 and 45 °C. It was also observed that the steric hindered mono- and dinuclear Pd(II) complexes were thermally stable complexes and were not sensitive to air or the moisture. The complexes were easily prepared from cheap materials that could be used as versatile and efficient catalysts for different C-C coupling reactions (Suzuki-Miyaura reactions).     

IR, Raman and SERS spectra of 2-phenoxymethylbenzothiazole

The FT-IR and FT-Raman spectra of 2-phenoxymethylbenzothiazole were recorded and analyzed. The surface enhanced Raman scattering (SERS) spectrum was recorded in a silver colloid. The vibrational wavenumbers of the compound have been computed using the Hartree–Fock/6-31G* basis and compared with the experimental values. The appearance of the Ag–O stretching mode at 237 cm⁻¹ in the SERS spectrum along with theoretically calculated atomic charge density, leads us to suggest that the molecule is adsorbed through the oxygen atom with the molecular plane tilted on the colloidal silver surface. The direction of charge transfer contribution to SERS has been discussed from the frontier orbital theory.     

Transformation of 2,4-dichlorophenol by H2O2/UV-C, Fenton and photo-Fenton processes: Oxidation products and toxicity evolution

In the present study, H₂O₂/UV-C, Fenton and photo-Fenton treatment of 2,4-dichlorophenol was compared in terms of oxidation products and acute toxicity. The oxidation products were identified by gas chromatography-mass spectroscopy, high performance liquid chromatography and ion chromatography, whereas changes in acute toxicity were evaluated by the Vibrio fischeri luminescence inhibition assay. H₂O₂/UV-C and photo-Fenton processes ensured complete 2,4-dichlorophenolremoval, detoxification and significant mineralization. Hydroquinone and formic acid were identified as the common oxidation products of the studied advanced oxidation processes investigated. 3,5-dichloro-2-hydroxybenzaldehyde, phenol, 4-chlorophenol and 2,5-dichlorohydroquinone were identified as the additional H₂O₂/UV-C oxidation products of 2,4-dichlorophenol. Acute toxicity decreased with decreasing 2,4-dichlorophenol and increasing chloride release.     

Thermal degradation mechanisms of aluminium phosphinate, melamine polyphosphate and zinc borate in poly(methyl methacrylate)

The aim of this study was to investigate the thermal degradability, and in particular, the thermal degradation mechanism of organophosphorus flame-retardant poly(methyl methacrylate) (PMMA). For this purpose thermogravimetry and direct pyrolysis mass spectrometry analyses were used. Release of diethylphosphinic acid, melamine, and several products involving Al-O-P and N-P linkages were detected from the organophosphorus additive containing aluminium diethylphosphinate, melamine polyphosphate and zinc borate. When incorporated in PMMA, reactions of diethylphosphinic acid, melamine and/or their derivatives with the ester group affected the decomposition pathways by generation of (C₂H₅)₂POOCH₃ and HNCO at relatively high temperatures.     

Hetero‐ and homo‐leptic Ru(II) catalyzed synthesis of cyclic carbonates from CO2; Synthesis,spectroscopic characterization and electrochemical properties

Based on the a ligand BDPPZ [(9a,13a‐dihydro‐4,5,9,14‐tetraaza‐benzo[b]triphenylene‐11‐yl)‐phenyl‐methanone] (1) and its polypyridyl hetero‐ and homoleptic Ru(II) metal complexes, [Ru(bpy)₂L](PF₆)₂ (2), [Ru(phen)₂L](PF₆)₂ (3), [Ru(dafo)₂L](PF₆)₂ (4), [Ru(dcbpy)₂L](PF₆)₂ (5) and [RuL₃](PF₆)₂ (6) (where, L = ligand, bpy = 2,2′‐bipyridine, phen = 1,10‐phenantroline, dafo = 4,5‐diazafluoren‐9‐one and dcbpy = 3,3′‐dicarboxy‐2,2′‐bipyridine), have been synthesized and characterized by elemental analysis, UV–vis, FT‐IR, ¹H and ¹³C‐NMR spectra (for ligand), molar conductivity measurements and X‐ray powder techniques. The electrochemical parameters of the substituted ligand and its polypyridyl hetero‐ and homoleptic Ru(II) metal complexes are reported by cyclic voltammetry. UV–vis spectroscopy is used to compare the differences between the conjugated π systems in this ligand and its Ru(II) metal complexes. The polypyridyl hetero‐ and homoleptic Ru(II) metal complexes also tested as catalysts for the formation of cyclic organic carbonates from carbon dioxide and liquid epoxides which served as both reactant and solvent. The results showed that the [Ru(L)₃](PF₆)₂ (6) complex is more efficient than the other Ru(II) complexes for the formation of cyclic organic carbonates from carbon dioxide. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis and asymmetric catalytic activity of (1S,1′S)-4,4′-biquinazoline-based primary amines

A series of (1S,1′S)-4,4′-biquinazoline-based primary amines were prepared from natural amino acids via a six-step reaction sequence of protection and condensation followed by key synthetic steps including chlorination, nickel(0)-mediated homocoupling, and deprotection. These novel amines were screened for the asymmetric ethylation of aryl aldehydes to yield alcohols with an (S)-configuration with enantiomeric excesses (ee) varying from 2% to 95%.     

Synthesis of new boron complexes: application to transfer hydrogenation of acetophenone derivatives

Two new boron complexes were synthesized from N‐[3‐(methylmercapto)aniline]‐3,5‐di‐tert‐butylsalicylaldimine ( LH ) with boron reagent BPh₃ or BF₃.Et₂O. These boron complexes are stable and easily soluble in protic solvents such as ethanol (C₂H₅OH) but hardly soluble in nonprotic solvents such as chloroform (CHCl₃), dichloromethane (CH₂Cl₂) and tetrahydrofuran (THF). All new boron complexes have been fully characterized by both analytical and spectroscopic methods. The catalytic activities of complexes [LBPh₂], 2 , and [LBF₂], 3 , in the transfer hydrogenation of acetophenone derivatives were tested. Stable boron complexes were found to be efficient catalysts in the transfer hydrogenation of aromatic ketones in good conversions up to 99% in the presence of iso‐PrOH/KOH. Copyright © 2011 John Wiley & Sons, Ltd.