Dendritic metal-free

The design of dendritic multiporphyrin systems [18] permits energy transfer over longer distances. The outer shell of the dendrimer shown in Fig. 5.14 is made up of eight porphyrin-zinc complexes as energy donor units. Excitation of the units of the outer shell leads to fluorescence emission of the metal-free porphyrin core as a result of energy transfer from the periphery to the energy acceptor [19]. 

The main emphasis has so far been placed on metal-containing catalysts, both in the field of dendritic catalysis and in organic catalysis in general. However, the current trend is increasingly towards catalysis with purely organic compounds. A number of example of such metal-free - and dendritic - catalysts,... 

A further category of (often partially) metal-directed, self-assembled supramole-cules is made up of dendritic systems in which metal ions are employed as links in the radiating strands.This category thus contrasts with the majority of reported dendrimers which employ solely metal-free covalent connectivity. ... 

In order to produce honeycomb patterned PLA films, additives such as organic surfactants or functional nanoparticles must be added in order to overcome the effects of the high hydrophobicity of PLA. One such example is the use of dendritic amphiphilic block copolymers of poly(L-lysine) and PLLA, synthesised by metal-free ring-opening polymerisation. Culture of the human epithelial HeLa cell line showed a distinct increase in cell density after 72 h of culture, indicating that honeycomb patterned polymers produced from such dendrimers are indeed biocompatible. ... 

This means that the density of the spherical particles of which a powder is composed is about twice as big as the apparent density of the powder. On the other hand, it is necessary to bear in mind that copper powder particles are dendritic by nature [42], hence they are porous. It is obvious that the free flow of a powder consisting of spherical particles can be expected only if the surface parts of the particles corresponding to the metal segments are larger than, or equal to, the pores between them. 

In any event. Mg deposition on bare metallic surfaces (oxide-film and passivation free) is not at all dendritic and is highly reversible. Figure 13.11 shows the typical Mg deposition morphology scanning electron microscopy, (SEM, images) in two types of Mg-Al-Cl-R complex solutions in THF. Mg... 

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