Molecular structure–property relationships for molecular electronics are beginning to emerge. Recent experiments lend credibility to the single-molecule nature of transport measurements and illustrate the molecular features that give rise to various interesting conductance behaviors (see picture).

Struktur-Eigenschafts-Beziehungen sind die Voraussetzung für den Einsatz von Molekülen als Komponenten in der molekularen Elektronik. Kürzlich konnten Einzelmoleküle in Transportmessungen analysiert werden. Die Ergebnisse verdeutlichen das bemerkenswerte Leitfähigkeitsverhalten von Einzelmolekülanordnungen (siehe Bild).

Dendrimers are potentially useful for encapsulation of core moieties. Although the conformation that a dendrimer assumes around a core moiety cannot be directly determined, the effect of increasing dendrimer size on the photophysical and electrochemical properties of the core has been documented. Specifically, studies of electroactive core dendrimers have shown attenuation of electron transfer rates with increasing dendrimer size, which is an indication of encapsulation. However, in two recent, independent reports of electroactive core dendrimers, electron transfer rates are not attenuated as the dendrimer size increases. These reports illustrate the caution that must be taken when inferring conformation from primary structure in dendritic macromolecules.

Die molekulare Elektronik ist zwar eine noch junge Disziplin, dennoch konnten bereits große Fortschritte erzielt werden, und wir erkennen heute sehr deutlich, welche Materialien geeignet sind und welche Eigenschaften sie aufweisen müssen. Dieser Aufsatz soll auf breiter Basis die derzeit vielversprechendsten Ansätze für eine molekulare Elektronik vorstellen und in ihre Teildisziplinen einführen. Wir behandeln zunächst die historische Entwicklung der konventionellen Elektronik und zeigen auf, welche Faktoren den Beginn der molekularen Elektronik ausgelöst haben. Die Probleme, die bei der Miniaturisierung konventioneller Bauelemente auftreten, werden ebenso diskutiert wie einige Lösungsansätze. Daran anschließend stellen wir die wichtigsten Ergebnisse auf diesem Gebiet vor, die einen tiefen Einblick in das Verhalten molekularer Systeme geben.

Molecular electronics is, relatively speaking, a young field. Even so, there have been many significant advances and a much greater understanding of the types of materials that will be useful in molecular electronics, and their properties. The purpose of this review is to provide a broad basis for understanding the areas where new advances might arise, and to provide introduction to the subdisciplines of molecular electronics. This review is divided into two major parts; an historical examination of the development of conventional electronics, which should provide some understanding of the push towards molecular electronics. The problems associated with continuing to shrink conventional systems are presented, along with references to some of the efforts to solve them. This section is followed by an in-depth look at the most important research into the types of behaviors that molecular systems have been found to display.

We are constructing a model system to elucidate the molecular structure-property relationships for attenuation of electron transfer (e.g. electron encapsulation). This information is relevant in bio-electron transfer schemes and in emerging molecular electronics schemes such as storage of information using individual molecules. Our system consists of an inorganic cluster surrounded by dendritic ligands which act as an organic coating. Although the electrochemical and photophysical properties of a variety of metal clusters have been established, very little has been described on the chemistry on metal clusters.