Alkylation of Rhodium Porphyrins Using Ammonium and Quinolinium Salts

Alkylation of rhodium­(III) porphyrins [RhIII(por)] was achieved under relatively mild conditions in up to 98% yields, where readily available ammonium and quinolinium salts were utilized as the alkylating agents. This transformation tolerates air and water, thus serving as a convenient method to prepare a variety of alkyl- and benzyl-RhIII(por) complexes. Preliminary mechanistic studies support an SN2-like reaction pathway involving a RhI(por) anion intermediate.