Vol. 105 No. 3 (2009)

This article introduces an alternative view to ylide nature that allows the definition of carbon ylides. Their physical and chemical properties, as well as the attempts directed to the synthesis of carbon bisylides are also reviewed. The highly non canonical bonding situation in such compounds forces an interpretation as coordination compounds, in which carbon serves as a central atom that interacts with its ligand sphere via donor-acceptor bonds.

The detection of specific DNA sequences has an enormous diagnostic and clinical potential because of the genetic origin of many pathologies, and the influence of particular genotypes in the response to medical treatments. Current methods for the specific detection of DNA sequences are based on hybridization of single-stranded DNA fragments to complementary sequences conveniently conjugated to fluorescent reporters. However, the advantages offered by directly probing double-stranded DNA have encouraged the search for new methods for such direct detection. Herein we review the current developments in this field, most of them based in the modification of known double-stranded DNA-binding agents like hairpin polyamides.

In this work, we exposed a brief report about the development of the asymmetric aminocatalysis by using secondary-amines such as the initial enantioselective aldol reactions, the iminium activation, or the last organocatalytic tandem and cascade reactions. These pioneer works have opened a new research area in asymmetric catalysis in which is possible to developed new synthetic tools. The asymmetric aminocatalysis is currently being applied to the synthesis of drugs or bioactive compounds (e.g. Tamiflu®).

Keywords: organocatalysis, proline, aldehydes, ketones, secondary amines

Nonstop use of bioresistent polyolefins is beginning to be a serious problem to our society. The work showed here gives us a global vision for a better understanding of the problem and proposes the polyesters as an interesting alternative to polyolefins. Herein we describe in detail the types of polyesters, origin, classification, synthetic methods, and current applications.

This paper presents a review of methods for analysis of metallic elements, mainly for Cu and Zn, in agricultural soils, highlighting those most commonly used. Some of the methods described have a greater scope, and have been used in analysis of sediments, sludge, sewage sludge, sewage sludge amended soils, polluted soils, etc. It also outlines some possible lines of future development of these methods.

Dangerous situations connected with fire can be created in daily life and they can have serious consequences without a basic scientific information. Not knowing what to do in these cases and being unfamiliar with the adequate use of each fire extinguisher, may provoke that a small fire becomes a huge one. In consequence, the best safety measure is the knowledge of the different chemical agents´ properties. With this purpose, experiences of their properties as well as their behaviours against different types of fires are shown.

Keywords: fire, extinction ways, fire extinguisher agents

In this article the preparation of jam is proposed as a didactic resource, that serves as reason for the study of a set of physical and chemical phenomena related to the process and the own jam. Although a qualitative analysis is proposed, the exposed ideas can be developed more quantitatively.

Metallic electroplates and the technique used to produce them (Electroplating) are very important in the actual technologic world. In this work, the advent and development of metal deposition and related techniques are described. Researchers who contribute to Electroplating development through its history are also mentioned.

Based in a partition of the Nobel Prizes in Chemistry (154) into 19 fields, young chemists are encouraged to work in a field that could lead to the first Spanish Nobel Prize in Chemistry.

Keywords: Nobel Prize, ordinary science, revolucionary science, Kuhn, Watson