New copper(II) complexes produced by the template reaction of acetoacetic-2-pyridylamide and amino-aliphatic alcohols

The template condensation of acetoacetic-2-pyridylamide with amino aliphatic alcohols such as 2-aminoethanol (HL1) and 3-amino propanol (HL2) in the presence of copper(II) ions gave octahedral complexes, which have been characterized by elemental analyses, u.v.-vis. and i.r. spectra, conductivity, d.t.a, magnetic and e.s.r. measurements. The molar conductance in DMF indicate that the complexes are non-ionic in character. The e.s.r. spectra of solid complexes (2) and (5) at room temperature indicate axial type symmetry (dx2-y2) with covalent bond character.     

Near-infrared fluorescent probes: a next-generation tool for protein-labeling applications

The development of near-infrared (NIR) fluorescent probes over the past few decades has changed the way that biomolecules are imaged, and thus represents one of the most rapidly progressing areas of research. Presently, NIR fluorescent probes are routinely used to visualize and understand intracellular activities. The ability to penetrate tissues deeply, reduced photodamage to living organisms, and a high signal-to-noise ratio characterize NIR fluorescent probes as efficient next-generation tools for elucidating various biological events. The coupling of self-labeling protein tags with synthetic fluorescent probes is one of the most promising research areas in chemical biology. Indeed, at present, protein-labeling techniques are not only used to monitor the dynamics and localization of proteins but also play a more diverse role in imaging applications. For instance, one of the dominant technologies employed in the visualization of protein activity and regulation is based on protein tags and their associated NIR fluorescent probes. In this mini-review, we will discuss the development of several NIR fluorescent probes used for various protein-tag systems.

This minireview describes the development of NIR chemical probes for various protein-tag systems.     

Kinetic studies on the solvolysis and axial ligand substitutions of bis-triphenylphosphine(cyclohexane-1,2-dione-dioximato)ruthenium(II) in non-aqueous solvents

Kinetic studies of ligand substitutions of the six-coordinated Ru^II pseudo-macrocyclic complex [Ru(CHDH)₂- (PPh₃)₂] (CHDH=cyclohexanedione-dioximato) have been spectrophotometrically investigated in a variety of solvents and at 70, 80, 85 and 90°C. The reactions studied are of the form:[(PPh₃)Ru(CHDH)₂(PPh₃)] + L =[(PPh₃)Ru(CHDH)₂L] + PPH₃ where L is imidazole, pyridine, piperidine or thiophene or a solvent molecule (PhCl, PhMe, MeCN, DMSO or DMF). The solvolysis reactions with chlorobenzene and toluene proceed to an equilibrium position favoring the bis-triphenylphosphine complex. All other reactions proceed to completion. From a mechanistic point of view the reactions were found to proceed through the formation of a five coordinate intermediate that possesses little or no discriminating ability towards the incoming nucleophiles. The rate data were thus interpreted in terms of a dissociative (D) or dissociative interchange (Id) mechanism. Activation parameters H and S are reported. Preliminary studies on the solvatochromic behavior of [Ru(CHDH)₂(PPh₃)₂] and the corresponding mixed complexes are discussed.     

Blends of starch with ethylene vinyl alcohol copolymers: effect of water,glycerol, and amino acids as plasticizers

Blends of thermoplastic starch with poly(ethylene‐co‐vinyl alcohol) copolymer (EVOH) were melt extruded with water/glycerol as plasticizer and a series of amino acid additives. The biggest factor in end‐use mechanical properties proved to be the relative humidity (RH) during storage. Plasticized starch‐EVOH blends stored at 0 and 50% RH changed significantly over time, with, for example, the tensile strength (TS) of the glycerol‐plasticized blend increasing from 4.7 to 26.3 MPa over 8 weeks when maintained at 0% RH. In contrast, the TS of this same sample stored at 75% RH remained unchanged for 8 weeks. Amino acids provided relatively minor, but significant changes in mechanical properties with time. Based on TS, elongation‐to‐break, and modulus, it may be concluded that β‐alanine, sarcosine, and L ‐proline were more effective than glycerol at maintaining strong flexible blends. Increases in crystallinity and changes in morphology with time, as described by modulated DSC were correlated to these changes in mechanical properties. Published in 2007 by John Wiley & Sons, Ltd.     

Environmentally degradable bio-based polymeric blends and composites

Blends and composites based on environmentally degradable-ecocompatible synthetic and natural polymeric materials and fillers of natural origin have been prepared and processed under different conditions. Poly(vinyl alcohol) (PVA) was used as the synthetic polymer of choice by virtue of its capability to be processed from water solution or suspension as well as from the melt by blow extrusion and injection molding. Starch and gelatin were taken as the polymeric materials from renewable resources. The fillers were all of natural origin, as waste from food and agro-industry consisted of sugar cane bagasse (SCB), wheat flour (WF), orange peels (OR), apple peels (AP), corn fibres (CF), saw dust (SD) and wheat straw (WS). All the natural or hybrid formulations were intended to be utilized for the production of: a) Environmentally degradable mulching films (hydro-biomulching) displaying, in some cases, self-fertilizing characteristics by in situ spraying of water solutions or suspensions; b) Laminates and containers to be used in agriculture and food packaging by compression and injection molding followed by baking. Some typical prototype items have been prepared and characterized in relation to their morphological and mechanical properties and tested with different methodology for their propensity to environmental degradation and biodegradation as ultimate stage of their service life. A relationship between chemical composition and mechanical properties and propensity to biodegradation has been discussed in a few representative cases.     

Anti-HIV Active Naphthyl Analogues of HEPT and DABO

Summary.  5-Isopropyl-6-naphthyl uracil and 5-isopropyl-6-naphthyl-2-thiouracil were alkylated to give N-1-(ethoxymethyl and methylthiomethyl) uracil and S²-cyclohexyl-thiouracil, respectively. 5-Ethyl-6-naphthyl uracil and 5-ethyl-6-naphthyl-2-thiouracil afforded N-1-(ethoxymethyl, methoxy-methyl, methylthiomethyl, acetoxyethoxy methyl and hydroxyethoxy methyl) uracil and S²-((2,2- diethoxyethyl), methoxycarbonylmethyl, ethoxycarbonylpropyl, methylthiomethyl, ethoxymethyl, methyl and cyclohexyl)-thiouracil upon alkylation. Received September 25, 2001. Accepted (revised) December 3, 2001     

Trichosides A and B,new withanolide glucosides from Tricholepis eburnea

Trichosides A (1) and B (2), new withanolide glucosides, have been isolated from the n-butanolic fraction of the 75% methanolic extract of aerial parts of Tricholepis eburnea. Their structures were elucidated through spectroscopic analysis including ESI-MS, 2D NMR and acid hydrolysis.     

Celestine blue as a new indicator in electrochemical DNA biosensors

Celestine blue(CB)was introduced as a new electroactive indicator in DNA biosensors.The interaction of CB with DNA was investigated by electrochemical and spectroscopic methods.The effect of buffer kind and p H on the electrochemical behavior of CB was studied.The peak currents of CB were linearly related to DNA concentration in the range of 5.0×10~(-9) to 1.0×10~(-7)mol/L.The detection limit of this approach was 4.76×10~(-10) mol/L.Based on spectrometry data a hypochromic effect was observed in UV-Vis spectra of CB with increasing DNA concentration.The results illustrate the possible interaction mode between CB and DNA is electrostatic binding.