Molecular Design of Anionic Phthalocyanines with π–π Stacking Columnar Arrangement. Crystal Structures, Optical, and Magnetic Properties of Salts with the Iron(I) Hexadecachlorophthalocyanine Anions

Abstract

Ionic compounds containing iron(I) hexadecachlorophthalocyanine anions have been obtained for the first time as single crystals: (PPN+){[Fe(I)Cl16Pc(−2)]−} (1), (Ph3MeP+)2{[Fe(I)Cl16Pc(−2)]−}(Br–)·C6H4Cl2 (2), and (PPN+)2[Fe(I, II)Cl16Pc(−2)]3(2−)·4C6H4Cl2 (3), where PPN+ is the cation of bis(triphenylphosphoranylidene)ammonium and Ph3MeP+ is the triphenylmethylphosphonium cation. The [Fe(I)Cl16Pc(−2)]− anions form closely packed π–π stacking columns in 1–3. Salts 1 and 2 with integer −1 charge on iron phthalocyanines have uniform and weakly dimerized columns, respectively. Salt 3 has two cations per three iron phthalocyanine molecules which are arranged in trimers within the columns. Different shift of phthalocyanines at the same interplanar distances of 3.33–3.38 A provides essentially shorter Fe···Fe distances in 3 (3.62–3.84 A) than those in 1 and 2 (5.07–5.45 A). Calculations show a strong LUMO–LUMO overlapping between [Fe(I)Cl16Pc(−2)]− in 1–3 with the overlap integrals of 4.1–7.6 × 10–3. Weak signa...