Wege zu dendritischen Netzwerken: Bis‐Dendrimere durch Verknüpfung von Kaskadenmolekülen über Metallzentren

Abstract

Mit dem gezielten Einbau von Terpyridin‐Metallkomplexen lassen sich, wie im Bild rechts schematisch dargestellt, zwei Dendrimere definiert miteinander verknüpfen. Die elektronischen Eigenschaften des Metallzentrums hängen dabei von der Dendrimerumgebung ab.

Michael Additions versus Cycloaddition Condensations with Ethyl Nitroacetate and Electron‐Deficient Olefins

“…Addition of a copper salt to the catalytic system dramatically increased the proportions of cycloadducts 4, which were often the sole reaction product (Table 2). Significant amounts of open-chain adducts 3 were obtained from phenyl vinyl sulfone (2 d) and methyl vinyl ketone (2 e), whereas in other reactions minor amounts of adducts 3 could be observed only at 30 8C (Table 2, entries 1,8).…”

“…These conditions represent the right balance between conversion, reaction time and nitroacetate consumption. The same ratio was applied to most of the reactions reported in Table 3 (entries 1-7), whereas larger excesses of 1 (2.5 equiv) were required for the less reactive substrates (entries [8][9][10]. N-Methylpiperidine (NMP) was employed as a base, except that N-methylmorpholine (NMM) was preferred in the case of methyl vinyl ketone (2 e; see entry 15 in Table 2).…”

Supramolekulare Elektrochemie

“…Diese Ergebnisse konnten durch neuere Arbeiten von Echegoyen, Newkome et al bestätigt werden. [90] Ein über mehrere Generationen aufgebautes Terpyridindendrimer wies bei der elektrochemischen Untersuchung ausschlieûlich Potentialkurven auf, die den beiden Reduktionen der Terpyridineinheit entsprachen. Wie bei den in Abschnitt 3 erwähnten Porphyrindendrimeren nimmt die Reversibilität der Redoxprozesse ab, wenn das Dendrimer mit zunehmender Generationenzahl sterisch anspruchsvoller wird.…”

Toward Modular Chemistry with the Dendritic Box as Module

“…The inside part is fuctionalized with an anchoring group and a spacer is used to make these large guests compatible with the shell [21]. When the large part that is outside the box becomes functional or possesses functional groups, it should be possible to build larger structures, comparable with the key-and-lock principle, recently published by Newkome et al [22]. It is very appealing to us to exploit the functionality of four as is found for the maximum number of many encapsulated guests.…”