Coordination Complexes of Pentamethylcyclopentadienyl Iridium(III) Diiodide with Tin(II) Phthalocyanine and Pentamethylcyclopentadienyl Iridium(II) Halide with Fullerene C60- Anions

Synthetic approaches to iridium complexes of metal phthalocyanines (Pc) and fullerene anions have been developed to give three types of complexes. The compound{(Cp*(IrI2)-I-III)(SnPc)-Pc-II(2-)}center dot 2C(6)H(4)Cl(2) (1) (Cp* is pentamethylcyclopentadienyl) is the first crystalline complex of a metal phthalocyanine in which an iridium(III) atom is bonded to the central tin(II) atom of Pc via a Sn-Ir bond length of 2.58 angstrom. In (TBA(+))(C-60(center dot-)){(Cp*(IrI2)-I-III)(SnPc)-Pc-II(2-)}center dot 0.5C(6)H(14) (2), the {(Cp*(IrI2)-I-III)(SnPc)-Pc-II(2-)} units cocrystallize with (TBA(+))(C-60(center dot-)) to form double chains of C-60(center dot-) anions and closely packed chains of {(Cp*(IrI2)-I-III)(SnPc)-Pc-II(2-)}. Interactions between the fullerene and phthalocyanine subsystems are realized through pi-pi stacking of the Cp* groups of {(Cp*(IrI2)-I-III)(SnPc)-Pc-II(2-)} and the C-60(center dot-) pentagons. Furthermore, the spins of the C-60(center dot-) are strongly antiferromagnetically coupled in the chains with an exchange interaction J/k(B) = -31 K. Anionic (TBA(+)){(Cp*(IrCl)-Cl-II)(eta(2)-C-60(-))}center dot 1.34C(6)H(4)Cl(2) (3) and (TBA(+)){(Cp*Ir-III)(eta(2)-C-60-)}center dot 1.3C6H4Cl2 center dot 0.2C6H14 (4) are the first transition metal complexes containing eta(2)-bonded C-60- anions, with the Cp*IrIICl and Cp*IrIII units eta(2)-coordinated to the 6-6 bonds of C-60-. Magnetic measurements indicate diamagnetism of the {(Cp*IrIICl)(eta(2)-C-60-)} and {(Cp*IrIII)(eta(2)-C-60-)} anions due to the formation of a coordination bond between two initially paramagnetic Cp*IrIICl or Cp*IrIII groups and C-60(center dot-) units. DFT calculations support a diamagnetic singlet ground state of 4, in which the singlet-triplet energy gap is greater than 0.8 eV. DFT calculations also indicate that the C-60 molecules are negatively charged.