Synthesis of imidazole and imidazolium porphyrins

Abstract

A new porphyrin compound, where an imidazole group was attached through the 1-position nitrogen to a phenyl ring located on the porphyrin periphery has been synthesized and characterized. The second nitrogen on the imidazole is available for further chemistry as demonstrated by the attachment of bromopentane forming the imidazolium porphyrin complex. This is the first example of an imidazolium group covalently attached to the porphyrin periphery in which the porphyrin is attached through the nitrogen on the imidazole ring rather than a carbon atom.

Synthesis and structural characterisation of the first N-heterocyclic carbene ligand fused to a porphyrin

“…The classical building blocks employed for this strategy are porphyrins bearing one or more peripheral coordination sites, as is well illustrated by the examples of porphyrins linked to pyridyl derivatives. 8,10 Surprisingly, the number of examples of porphyrins bearing N-heterocyclic carbene (NHC) ligands as external coordination site remains limited 11 and, to our knowledge, there is no example of NHC conjugated with the aromatic core of the porphyrin. Stable N-heterocyclic carbenes (NHCs), first isolated by Arduengo et al, 12 are versatile ligands for transition metal complexes and remain very important in the field of organometallic chemistry and homogeneous catalysis.…”