Química organometálica de superfície aplicada à preparação de catalisadores heterogêneos bem definidos

The study of the reactions of organometallic complexes with the surfaces of inorganic oxides, zeolites and metals constitutes the basis of Surface Organometallic Chemistry (SOMC). The basic rules of organometallic chemistry are often valid when applied to surfaces and well-defined surface organometallic complexes can be obtained. These complexes can be used as heterogeneous catalysts or, by controlled reactions, can be transformed in other species useful for a given catalytic reaction. In some cases, these catalysts exhibit higher activity and/or selectivity than their analogous molecular complexes.

A nova química do estanho

The organometallic chemistry of tin has experienced a phenomenal growth in the last decades. From virtually no important research or applications 50 years ago it has blossomed into a vigorous branch of the chemical sciences. This article aims at reviewing its characteristics and the reasons for this growth, concentrating on the current trends and the latest research in the area.

Experimentação em química de compostos organometálicos: preparação do cloreto de dicarbonilciclopentadienilferro(II)

In this work, we describe a new method for obtaining [Fe(CO)2[(eta5-C5H5)Cl] employing simple techniques and low-cost reagents. It is worth mentioning that this method is faster than others reported in the literature. It was applied in laboratory classes for undergraduate students, exploring different concepts in organometallic chemistry and discussing the steps involved in the synthetic route.

Catalisadores contendo carbenos n-heterocíclicos como ligantes: propriedades, sínteses, aplicações e comparação com outros ligantes

N-heterocyclic carbenes (NHCs) have become of considerable importance in modern organometallic chemistry and homogeneous catalysis. There are several advantages in the use NHCs over their phosphorus analogues, which explains the enormous development of NHC ligands in the field of organometallic catalysis in the past few years. In this article, we present an overview of the importance of the catalysts containing NHC ligands, their synthesis, some pertinent synthetic applications, and a brief comparison with other catalysts.

Estanilenos: organometálicos de estanho (II) σ - ligados a grupos orgânicos

This article provides a short review of the chemistry of stannylenes and their derivatives, including the preparation, spectroscopic properties, molecular structure and reactivity of the various species. The organometallic chemistry of Sn(II) is far less explored than that of its much more common Sn(IV) counterpart. Organometallics of main group metals have become increasingly important in recent years, which prompted us to present an overview of the situation regarding the case of Sn(II).

Síntese de heterociclos bioativos derivados do ferroceno

The discovery of ferrocene marked one of the points of departure for modern organometallic chemistry. In general, the compounds of ferrocene derivatives are widely applied in several areas. One of the most important applications of ferrocene is the development of more active drugs, especially in cases where there is resistance to current drugs. Bioactive agents containing ferrocene have proven effective in combating diseases such as cancer, malaria, HIV, Alzheimer and conditions caused by fungi and bacteria. In this context, the present paper aims to highlights the synthesis of heterocycles containing ferrocene moiety and their use in medicinal chemistry.

DNA-lipid systems: A physical chemistry study

It is well known that the interaction of polyelectrolytes with oppositely charged surfactants leads to an associative phase separation; however, the phase behavior of DNA and oppositely charged surfactants is more strongly associative than observed in other systems. A precipitate is formed with very low amounts of surfactant and DNA. DNA compaction is a general phenomenon in the presence of multivalent ions and positively charged surfaces; because of the high charge density there are strong attractive ion correlation effects. Techniques like phase diagram determinations, fluorescence microscopy, and ellipsometry were used to study these systems. The interaction between DNA and catanionic mixtures (i.e., mixtures of cationic and anionic surfactants) was also investigated. We observed that DNA compacts and adsorbs onto the surface of positively charged vesicles, and that the addition of an anionic surfactant can release DNA back into solution from a compact globular complex between DNA and the cationic surfactant. Finally, DNA interactions with polycations, chitosans with different chain lengths, were studied by fluorescence microscopy, in vivo transfection assays and cryogenic transmission electron microscopy. The general conclusion is that a chitosan effective in promoting compaction is also efficient in transfection.