A new near‐infrared switchable electrochromic polymer and its device application

A new near‐infrared switchable electrochromic polymer containing carbazole pendant (poly‐SNSC), synthesized by electrochemical polymerization of 2,5‐bis‐dithienyl‐1H‐pyrrole (SNS) main chain, has been prepared. The electrochemical and optical properties of SNSC monomer and its polymer have been investigated. Because of having two different electro‐donor moieties; that is, carbazole and SNS, SNSC gave two separate electrochemical oxidation and also light brown color of the film in the neutral state turn into gray on oxidation. An electrochromic device, contructed in the sandwich configuration [indium tin oxide (ITO)‐coated glass/anodically coloring polymer (poly‐SNSC)//gel electrolyte//cathodically coloring polymer (PEDOT)/ITO‐coated glass] and exhibited a high coloration efficiency (1216 cm² C^–1), a very short response time (about 0.3 s), low driving voltage, and a high redox stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Microwave-Induced Solvent-Free Synthesis and Antifungal Screening of Novel Spiro Heterocyclic Systems Containing 3,5-Diphenyl-7H-thiazolo[3,2-a]pyrimidine and Indolin-2-one

A microwave-induced technique has been developed for the synthesis of a series of novel spiro indoline-based heterocycles (7a–g) at atmospheric pressure in an open vessel using an environmentally benign procedure. This rapid method produces pure products in good yields within a few minutes in comparison to the conventional procedure developed for the synthesis of these heterocycles. The synthesized compounds have been screened in vitro for antifungal activity against two fungal strains (i.e., Aspergillus niger and Aspergillus flavus). All compounds have shown significant activity against these pathogens.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

Monolithic packed 96‐tips set for high‐throughput sample preparation: determination of cyclophosphamide and busulfan in whole blood samples by monolithic packed 96‐tips and LC‐MS

A monolithic methacrylate packed 96‐tips device was used for the extraction of the busulfan and cyclophosphamide in whole blood samples. Using a packed 96‐tips set, a 96‐well plate could be handled in about 2 min. The key aspect of the monolithic phase is that monolithic material can offer both good extraction capacity and low‐back‐pressure properties. The validation of the methodology showed that the accuracy values of quality‐control samples were between 99 and 113% for busulfan, and between 103 and 110% for cyclophosphamide. The inter‐day precision ranged from 7.0 to 12% for busulfan and from 13 to 16% for cyclophosphamide. The standard calibration curves were obtained within the concentration range 5–2000 nm for busulfan and from 10 to 5000 nm for cyclophosphamide in blood samples. The coefficients of determination were ≥0.99. Copyright © 2012 John Wiley & Sons, Ltd.     

Impact of ionic strength of growth on the physiochemical properties, structure, and adhesion of Listeriamonocytogenes polyelectrolyte brushes to a silicon nitride surface in water

The adhesion energies between pathogenic Listeriamonocytogenes EGDe to a model surface of silicon nitride were quantified using atomic force microscopy (AFM) in water for cells grown in pure media (as the control) and in media of four different ionic strengths of added NaCl (IS of 0.05 M, 0.1 M, 0.3 M and 0.5 M NaCl). The physiochemical properties of L. monocytogenes EGDe surface brushes were shown to have a strong influence on the adhesion of the microbe to the silicon nitride surface. The transitions in the adhesion energies, physiochemical properties, and the structure of bacterial surface polyelectrolyte brushes were observed for the cells grown in the media of 0.1 M added NaCl. Our results suggested that the highest long-range electrostatic repulsion which was partially balanced by the Liftshitz-van der Waals attraction for the cells grown at 0.1 M was responsible for the highest energy barrier to adhesion for these cells as predicted by the soft-particle analysis of DLVO theory and the lower adhesion measured by AFM.     

Synthesis, IR spectral studies and quantum-chemical calculations on 1,2-dihydronaphto[1,2-e]oxazine-3-thiones and 3,4-dihydrobenzo[e][1,3]oxazine-2-thione

2-Hydroxy-1-naphthaldehyde (1) was reacted with substituted anilines to afford 1-(substituted phenyliminomethyl)naphthalen)-2-ols (2). The reduction of these imines by NaBH₄ gave 1-((substituted phenylaminomethyl)naphthalen)-2-ols (3) which were cyclized with thiophosgene to give corresponding 2-substituted phenyl-1,2-dihydronaphto[1,2-e]oxazine-3-thiones (4). 3-p-Tolyl-3,4-dihydrobenzo[e][1,3]oxazine-2-thione (8) was also obtained by the same way. The structures of these new compounds were determined by ¹H NMR, IR spectroscopic data and elemental analyses. AM1, PM3 and ab initio (at Hartree–Fock level with 3-21G basis set) methods were used to study the molecular geometry of the compounds. A complete infrared spectral analysis of the oxazines has been performed in this paper. Observed frequencies of the molecules were compared with calculated normal mode analysis which was carried out on the basis of RHF/3-21G method. Assignments of vibrational bands (in the range of 1760–400 cm⁻¹) have been performed by taking into account the results of the ab initio vibrational analysis. The mechanism of the cyclization reaction between (3a) and thiophosgene was studied by the semi-empirical AM1 and ab initio (RHF) calculations.     

Sulfonyl transfer mechanism in C-S coupling of phenylmagnesium bromide with phenyl arenesulfonates

The kinetics of C-S coupling of phenylmagnesium bromide with phenyl arenesulfonates has been studied in THF:toluene (7:10) at 90 °C. Kinetic data and Hammett relationship are consistent with an asynchronous S_Na mechanism in which rate determining thiophilic attack of carbanion takes place much ahead of phenoxy group departure.     

Fluorescent aminoarylcyclotetraphosphazenes

In the present work, octachlorocyclotetraphosphazatetraene (1), N₄P₄Cl₈, is reacted with aniline (2), 1-napthylamine (4) and 2-aminoanthracene (6) to give octakis(arylamino)cyclotetraphosphazenes (3, 5 and 7). These cyclotetraphosphazene compounds (3, 5 and 7) have been fully characterized by elemental analysis, mass (MS), FT-IR, ¹H and ³¹P NMR spectroscopies. The molecular and crystal structures of 5 have been characterized by X-ray crystallography. The structure of 5 is monoclinic with the space group P21/c. The octakis(1-napthylamino)-(5) and octakis(2-aminoanthracene)-(7) cyclotetraphosphazene compounds have been synthesised for the first time in this study. The fluorescence properties of 3, 5 and 7 have been investigated in tetrahydrofuran (THF) and have been shown to have highly fluorescence behavior. This work also presents the quenching of arylamino substituted cyclotetraphosphazene derivatives (3, 5 and 7) by p-benzoquinone (BQ) or hydroquinone (HQ).     

Synthesis,structure, and solvent-extraction properties of tridentate oxime ligands and their cobalt(II), nickel(II), copper(II), zinc(II) complexes

Synthesis of four different types of ligands Ar[COC(NOH)R] _n (Ar = biphenyl, n = 1, HL¹; Ar = biphenyl, n = 2, H₂L²; Ar = diphenylmethane, n = 1, HL³; Ar = diphenylmethane, n = 2, H₂L⁴; R = furfurylamine in all ligands) and their dinuclear Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ complexes is reported herein. These compounds were characterized by elemental analysis, ICP-OES, FT-IR spectra, and magnetic susceptibility measurements. The ligands were further characterized by ¹H NMR. The results suggest that dinuclear complexes of HL¹ and HL³ have a metal to ligand mole ratio of 2: 2 and dinuclear complexes H₂L² and H₂L⁴ have a metal to ligand mole ratio of 2: 1. Square pyramidal or octahedral structures are proposed for complexes of oxime ligands. Furthermore, extraction abilities of the four ligands were also evaluated in chloroform using selected transition metal picrates such as Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Pb²⁺. The ligands show strong binding ability towards Hg²⁺ and Cu²⁺ ions.     

One-pot multicomponent synthesis of some 5,6-dihydro-benzo[h]quinoline derivatives

5,6-Dihydrobenzo[h]quinoline derivatives 4a–f and 5a–c were prepared via condensation of the corresponding arylidenes 2, with 1-tetralone in the presence of ammonium acetate and sodium methoxide, respectively, following thermal, microwave and ultrasound methodologies. The yields of 4a–f were moderate when the latter two methodologies used, but the products were pure. Ultrasound and microwave irradiation methods were also used in the synthesis of 4-aryl-3-cyano-1,2,5,6-tetrahydro-benzo[h]quinoline-2-ones (6a–e) and its analogues 7a,b. The majority of compounds 4–7 were synthesized via one-pot multicomponent reactions of aldehydes, active cyanomethylene compounds, 1-tetralone and ammonium acetate. Attempts to cyclocondensation of the aminocyano derivative 4a,d with acetic anhydride in presence of conc. H₂SO₄ failed; instead the acetylamino derivative 8 was isolated. On the other hand, refluxing of 4d with formamide in DMF led to the formation of dihydrobenzo-pyrimidoquinoline 9 giving good yield. All prepared condensates were structurally elucidated by various spectroscopic methods. Screening of the potential cytotoxicity for compounds 4a–f on five cell lines, namely: colorectal carcinoma (HCT-116), Hepatocellular carcinoma (HEPG2), Human breast adenocarcinoma (MCF7), Cervix adenocarcinoma (HELA) and Glioblastoma (U251), did not show any cytotoxic activity.     

Specific Interaction of the Legume Lectins, Concanavalin A and Peanut Agglutinin, with Phycocyanin

In a recent study, we found that jacalin, a T-antigen specific lectin could interact with phycocyanin (PC) in a carbohydrate-independent manner. We show here that concanavalin A and peanut agglutinin too can interact with PC, although the nature of the interaction is distinctly different from that for jacalin. The legume lectins bind PC weaker in the presence of their specific carbohydrate ligands. Like jacalin, the legume lectins too interact with PC via two distinct sites. Higher ionic strengths resulted in a weakening of the interaction at site 1 and did not affect the interaction at site 2 , clearly indicating that the interactions involve charged residues at the former and hydrophobic interactions at the latter site. The implications for the use of these lectin–PC complexes in photodynamic therapy and other clinical applications are discussed.