Perylene hydrogen-bonded

Beton and co-workers extended the hydrogen bonding approach to two-component systems, generating a number of structures that utilise different molecular motifs.24 26 In the case of perylene tetracarboxylic diimide (PTCDI) co-adsorbed with melamine (1,3,5-triazine-2,4,6-triamine) on a silver-terminated silicon surface, a network is formed in which the straight edges correspond to PTCDI with melamine at the vertices (Figure 11.6). The network shows large-area pores that the authors used to trap heptamers of C6o molecules. 

Figure 5.22 Cu UPD on a Au/mica substrate modified by a hybrid nanostructure consisting of a hydrogen-bonded network and a thiol SAM. (a) Cartoon ofthe hybrid structure and molecular structures of the components. The hydrogen-bonded network is composed of 1,3,5-triazine-2,4,6-triamine (melamine, triangles) and perylene-3,4,9,10-tetracarboxylic di-imide (PTCDI, rectangles) that interact via a triple hydrogen bond (dotted lines). Pores ofthe...

Dyes can also be incorporated into hydrogen-bonded superstructures using the complementarity of the hydrogen bond donors and acceptors. The addition of a perylene bisimide dye to chiral dialkyl melamine derivatives leads to aggregates (Fig. 26) which show induced circular dichroism in the dye part of the assembly in methylcyclohexane as well as the formation of mesoscopic fibres when the solvent is evaporated [227]. The melamine compounds... 

As we have discussed in depth elsewhere, despite the similarities in the structures of hypericin and hypocrellin, which are centered about the perylene quinone nucleus, their excited-state photophysics exhibit rich and varied behavior. The H-atom transfer is characterized by a wide range of time constants, which in certain cases exhibit deuterium isotope effects and solvent dependence. Of particular interest is that the shortest time constant we have observed for the H-atom transfer is 10 ps. This is exceptionally long for such a process, 100 fs being expected when the solute H atom does not hydrogen bond to the solvent [62]. That the transfer time is so long in the perylene quinones has been attributed to the identification of the reaction coordinate with skeletal motions of the molecule [48, 50]. 

Fig.31 Self association of a oligo(p-phenylenevinylenes) and perylenes as well as b olig(p-phenylenevinylenes) via quadruple hydrogen bonds...

Recently, Braunschweig and co-workers reported the assembly of a three-component hydrogen bonding array 19-20-19 in toluene. The system is composed of two diketopyrrolopyrrole electron donors and one perylene bisimide (PDI) electron acceptor (Fig. 6.13) [56]. The hydrogen bonded three-component array stacked further into ID helical hierarchical stracture. Fluorescence and transient absorption spectroscopy showed that photoexcitation of the donor-acceptor superstmctures with visible light directed the system to achieve fast charge separation. 

Neutral PVK and perylene have been coassembled within the interlayers of layered double hydroxide nanosheets to get ultra-thin films using the hydrogen bond layer-by-layer assembly method [93]. 

Supramolecular engineering of perylene bisimide assembHes based on complementary multiple hydrogen bonding interactions 13AJO 708. 

Another, less direct, approach to manipulate molecules on a surface is through the use of chemical self-assembly principles derived from X-ray crystallographic work. A two-dimensional hydrogen bonding motif derived from crystal-engineering studies has been used to assemble a two-dimensional honeycomb lattice based on the hydrogen bonded triad motif formed between perylene tetracarboxylic acid diimide (5.1) and melamine (5.2). The honeycomb... 

For the majority of perylene pigments, both color and stability properties derive from electronic pi-pi interactions. However, for Pigment Violet 29 (6), the unsubstituted diimide, hydrogen bonding between the imide hydrogens and the carbonyl groups is also possible, and is undoubtedly the reason for the added stability of this perylene pigment. 

Hydrogen-Bonded Perylene Bisimide and Related Assemblies. 91... 

---