{CpFeII(CO)2SnII(Macrocycle•3–)} Radicals with Intrinsic Charge Transfer from CpFe(CO)2 to Macrocycles (Cp: Cp or Cp*); Effective Magnetic Coupling between Radical Trianionic Macrocycles•3–

Neutral {CpFeII(CO)2[SnII(Pc•3–)]} {Cp is cyclopentadienyl (1, 2) or Cp* is pentamethylcyclopentadienyl (3); Pc: phthalocyanine}, {Cp*FeII(CO)2[SnII(Nc•3–)]} (4, Nc: naphthalocyanine), and {CpFeII(CO)2[SnII(TPP•3–)]} (5, TPP: tetraphenylporphyrin) complexes in which CpFeII(CO)2 fragments (Cp: Cp or Cp*) are coordinated to SnII(macrocycle•3–) have been obtained. The product complexes were obtained at the reaction of charge transfer from CpFeI(CO)2 (Cp: Cp or Cp*) to [SnII(macrocycle2−)] to form the diamagnetic FeII and paramagnetic radical trianionic macrocycles. As a result, these formally neutral complexes contain S = 1/2 spins delocalized over the macrocycles. This provides alternation of the C–Nimine or C–Cmeso bonds in the macrocycles, the appearance of new bands in the near-infrared spectra of the complexes, and blue shift of both Soret and Q-bands. The {CpFeII(CO)2SnII(macrocycle•3–)} units (Cp: Cp or Cp*, macrocycle: Pc or Nc) form closely packed π-stacking dimers in 1 and 3 or one-dimensional chains in 2 and 4 with effective π–π interaction between the macrocycles. Such packing allows strong antiferromagnetic coupling between S = 1/2 spins. Magnetic interaction can be described well by the Heisenberg model for the isolated dimers in 1 and 3 with exchange interaction J/kB = −78 and −85 K, respectively. Magnetic behavior of 2 and 4 is described well by the model that includes contributions from an antiferromagnetically coupled S = 1/2 dimer (Jintra) and a Heisenberg S = 1/2 chain with alternating antiferromagnetic spin exchange between the neighbors (Jinter). Compound 2 demonstrates large intradimer interaction of Jintra/kB = −54 K and essentially weaker interdimer exchange interactions of Jinter/kB = −6 K, whereas compound 4 shows strong magnetic coupling of spins within the dimers (Jintra/kB = −170 K) as well as between the dimers (Jinter/kB = −40 K). Compound {CpFeII(CO)2[SnII(TPP•3–)]} (5) shows no π–π interactions between the porphyrin macrocycles, and magnetic coupling is weak in this case (Weiss temperature is −5 K). Preparation of a similar complex with indium­(III) chloride phthalocyanine yields {CpFe­(CO)2[In­(Pc2–)]} (6). In this complex, indium­(III) atoms are reduced instead of the phthalocyanine macrocycles that explains electron paramagnetic resonance silence of 6 in the 4–295 K range.