Synthesis and Electrochemical Studies of Porphyrin Dimers Linked by Metallocarbenes

The functionalization of porphyrins
at the meso positions by azoles led, after subsequent
alkylation, to several
precursors of N-heterocyclic carbenes. Porphyrin dimers linked by
palladium (or rhodium) bis-carbene spacers were prepared and characterized.
Spectroscopic data and X-ray structures showed that the coordination
geometry for the two carbenes around the palladium linker was trans-anti. Electrochemical studies revealed significant
electronic communication between the two porphyrins, despite the absence
of conjugation pathways.