Structural control of metalloporphyrinogens by macrocycle modification: steric blocking of the macrocyclic cavity through transN,N-dimethylation

Reactions of potassium metal with trans-N,N-dimethyl-meso-octaethylporphyrinogen or meso-octaethyldioxaporphyrinogen afford dipotassium complexes with one potassium cation excluded from the cavity on steric grounds in the former case, or both potassium cations bound inside the macrocyclic cavity in the latter case.