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

Structural control of metalloporphyrinogens by macrocycle modification was discussed. Reactions of potassium metal with trans-N,N'-dimethyl-meso- octaethylporphyrinogen or meso-octaethyldioxaporphyronogen afford dipotassium complexes with one potassium cation excluded from the cavity on steric grounds in the former case. It was found that both potassium cations are bound inside the macrocyclic cavity in the latter case. It was also found that the reactions of potassium metal with macrocycles reach completion after several hours reflux.