{CpFe^II(CO)₂Sn^II(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–

[Image: see text] Neutral {CpFe(II)(CO)(2)[Sn(II)(Pc(•3–))]} {Cp is cyclopentadienyl (1, 2) or Cp* is pentamethylcyclopentadienyl (3); Pc: phthalocyanine}, {Cp*Fe(II)(CO)(2)[Sn(II)(Nc(•3–))]} (4, Nc: naphthalocyanine), and {CpFe(II)(CO)(2)[Sn(II)(TPP(•3–))]} (5, TPP: tetraphenylporphyrin) complexes in which CpFe(II)(CO)(2) fragments (Cp: Cp or Cp*) are coordinated to Sn(II)(macrocycle(•3–)) have been obtained. The product complexes were obtained at the reaction of charge transfer from CpFe(I)(CO)(2) (Cp: Cp or Cp*) to [Sn(II)(macrocycle(2−))] to form the diamagnetic Fe(II) 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–N(imine) or C–C(meso) 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 {CpFe(II)(CO)(2)Sn(II)(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/k(B) = −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 (J(intra)) and a Heisenberg S = 1/2 chain with alternating antiferromagnetic spin exchange between the neighbors (J(inter)). Compound 2 demonstrates large intradimer interaction of J(intra)/k(B) = −54 K and essentially weaker interdimer exchange interactions of J(inter)/k(B) = −6 K, whereas compound 4 shows strong magnetic coupling of spins within the dimers (J(intra)/k(B) = −170 K) as well as between the dimers (J(inter)/k(B) = −40 K). Compound {CpFe(II)(CO)(2)[Sn(II)(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(Pc(2–))]} (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.