A new modular concept for the self-assembly of electron donor-acceptor complexes is presented that ensures (i) fine-tuning the strength of the complexation, (ii) controlling the electronic coupling to impact electron and energy transfer processes, and (iii) high solubility of the corresponding hybrid architectures. This task has been realized through developing a series of porphyrin-fullerene donor-acceptor systems held together by a Hamilton-receptor-based hydrogen-bonding motif. In this context, novel libraries of C60 monoadducts (1) containing cyanuric acid side chains and of tetraphenylporphyrin derivatives (2) involving the complementary Hamilton-receptor unit were synthesized. The association constants of the corresponding 1:1 complexes (1.2) connected by six hydrogen bonds were determined complementary by NMR and fluorescence assays. Their strength, which was found to be in the range between 3.7 x 10(3) and 7.9 x 10(5) M-1, depends on the nature of the spacers, namely, hexylene versus propylene chains. Finally, transient absorption studies revealed photoinduced electron transfer from ZnP to C60 in the corresponding 1.2 complexes, which generate radical ion pair states that are persistent well beyond the ns time scale. In the case of the analogous SnP complexes, energy instead of electron transfer was observed. This is due to the shift of oxidation potential caused by presence of Sn in the oxidation state of +4.

The self-assembly of chiral depsipeptide dendrons 4, which contain a cyanuric acid building block at their focal point, with the homotritopic Hamilton receptor 1 is reported. The 1:3 compositions of the resulting chiral supramolecular dendrimers, the association constants K(n), and the cooperativity of binding expressed by Scatchard plots and the Hill coefficients n(H) was determined by NMR titration experiments. The most pronounced positive cooperativity was found for the complexes 1 L(3) with L being the second-generation dendrons 4 c-e. The least stable complexes are formed with the bulky third-generation dendrons 4 f-h. Similar results are obtained by the corresponding complexation of the achiral Frechét-type first- to third-generation dendrons 3 with 1. Chiroptical investigations of 1:3 complexes of 1 and 4 reveal chirality transfer from the dendron to the Hamilton receptor as demonstrated by the appearance of new CD absorption bands at 310 nm.

Supramolecular dendrimers resulting from the self‐assembly of a series of dendrofullerens 2a–4b containing a cyanuric acid building block at their focal point with the homotritopic Hamilton receptor 1 were prepared. The 1:3 compositions of the supramolecular dendrimers as well as the association constants Kn and the cooperativity of binding expressed by Scatchard plots and Hill coefficients nH were determined by NMR titration experiments. The most pronounced positive cooperativity was observed for the 1:L3 complexes with L being first generation dendrons. With the bulky second generation dendrons less stable complexes are formed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The synthesis and characterisation of a new type of porphyrin-based tetrakis(Hamilton receptor) 1 is presented and the complexation of 1 with the chiral depsipeptide dendrons 7-12, with cyanuric acid functionalities as their focal points, is reported. The resulting first-to third-generation chiral supramolecular dendrimers 13-18 were characterised by NMR, UV/Vis and CD spectroscopy. Chirality transfer from the depsipeptide dendrons to the porphyrin core was demonstrated by CD spectroscopy in the case of the second-and third-generation complexes 15-18, whereas no chirality transfer and hence no diastereoselective formation of a chiral superstructure could be determined in the case of the first-generation systems. The intensities of the complexes' CD absorptions in