ABSTRACT
Synthetic access to a set of metallo- and free base bis-porphyrins has been provided by a stepwise approach involving sequential peptide and Suzuki couplings. Linking these porphyrins through a 3,3'-biphenyl bridge enables cooperative binding to ditopic ligands such as the bipyridyls. Association constants and binding stoichiometry has been determined by spectroscopic/spectrophotometric means and the differences in the binding affinities of a small series of diaza ligands is discussed in the context of structural fit and microscopic association constants.
Subject(s)
Biphenyl Compounds/chemistry , Metalloporphyrins/chemistry , Rotation , Dimerization , Models, Molecular , Molecular Conformation , Pyridines/chemistry , Zinc/chemistryABSTRACT
An olefination approach to the construction of covalently linked cyclic metalloporphyrin trimers is presented using fullerenes such as C(60) or C(70) as a template. Yields of the trimer approach 60%. In the absence of a template, the major product is the cyclic dimer (50% yield) with only a small amount of trimer (<10%) formed, indicating this is a template-directed approach.