Synthesis of nanometer-sized homo- and heteroorganometallic tripodaphyrins

Tripodaphyrins are tetrahedral or pyramidal assemblies in which a porphyrin macrocycle situated on the top of the molecule is ''supported'' by three ''legs'' consisting of linear arrays of covalently linked rigid constitutive elements. The edge-length at the ''base'' of the molecules which have been synthesized until now lies in the range from 3.2 to 6.5 nm. In some tripodaphyrins (3a-c) the chromophore situated on the top of the molecule differs on the complexed metal ion from the other three, which are located at the ends of the ''legs''. Owing to the dimensions of the molecules, no intramolecular interaction between the chromophores is observed, even in the presence of a paramagnetic Cu(II) chelate. (C) 1997 Elsevier Science Ltd.