Synthesis, structural and magnetic properties of ternary complexes of (Me4P+)·{[Fe(I)Pc(-2)](-)}·triptycene and (Me4P+)·{[Fe(I)Pc(-2)]-}·(N,N,N',N'-tetrabenzyl-p-phenylenediamine)0.5 with iron(I) phthalocyanine anions.

Ternary complexes of (Me4P(+))·{Fe(I)Pc(-2)}·TPC (1) and (Me4P(+))·{Fe(I)Pc(-2)}·(TBPDA)0.5 (2) containing iron(I) phthalocyanine anions, tetramethylphosphonium cations (Me4P(+)), and neutral structure-forming triptycene (TPC) or N,N,N',N'-tetrabenzyl-p-phenylenediamine (TBPDA) molecules have been obtained as single crystals. In contrast to previously studied ionic compounds with monomeric (Fe(I)Pc(-2) anions, the anions form coordination {Fe(I)Pc(-2)}2 dimers both in 1 and 2, in which a nitrogen atom of one phthalocyanine anion weakly coordinates to the iron(I) atom of neighboring Fe(I)Pc(-2). The Fe···N distances in the dimers are 3.08(1) and 3.12(1) Å in 1 at 280 K and 2.986(5) (100 K) and 3.011(5) Å (180 K) in 2. The {Fe(I)Pc(-2)}2 dimers are packed in the layers in 1 arranged parallel to the ac plane and in isolated chains in 2 arranged along the a axis. Extended Hückel based calculation of intermolecular overlap integrals showed stronger and weaker π-π interactions within and between phthalocyanine dimers, respectively, both in 1 and 2. EPR signals of both complexes manifest two components. An major low-field asymmetric component is attributed to the Fe(I) atoms with the d(7) configuration. An origin minor narrow signal with g-factor close to the free-electron value (g = 2.0018-2.0035) is assigned to partial electron density transfer from the iron(I) center to the phthalocyanine macrocycle and the formation of the Fe(II)Pc(-3) species. Effective magnetic moments of the complexes of 1.69 (1) and 1.76 μB (2) correspond to the contribution of about one S = ½ spin per formula unit in accordance with low-spin state of Fe(I)Pc(-2). Negative Weiss temperatures of -7.6 K (1) and -13 K (2) in the 30-300 K range indicate antiferromagnetic interaction of spins in the phthalocyanine dimers. The multicomponent approach was previously proposed for the anionic fullerene complex formation. It also seems very promising to design and synthesize anionic phthalocyanine complexes with one- and two-dimensional macrocycle arrangements.