One or two ferrocenes were linked to the b-pyrrole positions of the free base TPP or its zinc complex through an ethynyl or ethynylenephenylene group using a modification of the Sonogashira method. All the compounds were characterized using UV-vis, FAB-mass and NMR spectroscopy and cyclic voltammetry.Ferrocenes and porphyrins are among the most intriguing molecules due to their electrochemical and catalytic properties. Several studies were devoted to their reciprocal interactions through the covalent bonds or supramolecular contacts. 1Many dyads or triads containing ferrocenes and porphyrins were synthesized in order to investigate the energy and/or electron transfer induced by light.2 Furthermore, different p-conjugated organic bridges were proposed and investigated as connecting molecular wires between several chromophores. They include oligo-phenylenevinylene, 3 oligo-phenyleneethynylenes, 4 oligo-acetylenes, 5 oligo-thiophenes, 6 and oligophenylenes. 7 In all these cases the wire-like behavior -efficient or inefficient -depends on the combination of several factors including the degree of conjugation in the bridge, orbital matching, donor-bridge energy gap, etc. 8During our investigations on the electronic properties of dyads containing porphyrins and fullerenes, we reported on the properties of dyads containing such monomers linked by oligo-ethynylenephenylene bridges. 9 The presence of one or more triple bonds connecting porphyrins and ferrocenes can provide interesting and unusual properties to the dyads due to their reciprocal electronic interactions and the rigidity of the structure.

A synthetic route for obtaining a porphyrin-fullerene dyad with a constrained geometry forcing the [60]fullerene sphere to lie on the porphyrin plane is reported, revealing a strong interaction in the ground state between the two chromophores.

Ruthenium meso-tetraphenylporphyrin was bound to a solid support, the Merrifield resin, and used in the cyclooligomerization of arylethynes, obtaining high yields and selectivities in the final products with a complete recycling of the catalyst.

The dimerization of arylethynes catalyzed by vanadium phthalocyanine to give substituted biaryls has been investigated. The reaction yield is always high and for many examples is only slightly affected by the aryl substituents. This fact is also related to the results obtained with metalloporphyrins, which give lower selectivities due to the presence of variable amounts of triphenylbenzenes.

Abstract:Cyclopropanation reaction is an important tool for obtaining interesting compounds and can be catalyzed by metalloporphyrins with high syn/anti ratio. The catalyst cannot be recycled and is usually lost during chromatographic separation from the two isomeric products. In this paper a meso-tetraphenylporphyrin rhodium(III) chloride was bound to a Merrifield resin and used to catalyze the cyclopropanation reaction of nine olefins, giving good yields and selectivities of the final products and for the first time, a partial recycling of the catalyst. This new catalytic system will be tested in the future for the synthesis of natural products containing cyclopropyl ring.