SnPhPc phthalocyanines with dianion Pc2− and radical trianion Pc˙3− macrocycles: syntheses, structures, and properties

Abstract

The interaction of Sn^IVCl₂Pc with an excess of NaBPh₄ in the presence of fullerenes C₆₀ and C₇₀ provides complete dissolution of Sn^IVCl₂Pc and the formation of blue solutions from which the crystals of [SnPhPc²⁻]⁺(BPh₄)⁻·C₆H₁₄ (1) or [SnPhPc˙³⁻]·C₆H₄Cl₂ (2) were selectively isolated. According to the optical spectra, salt 1 contains dianionic Pc²⁻ macrocycles, whereas macrocycles are reduced to form the Pc˙³⁻ radical trianions in 2. As a result, the phthalocyanine macrocycle is dianionic in 1, and the positive charge of Sn^IV is compensated by the Ph⁻, Pc²⁻, and BPh₄⁻ anions in this compound. The formally neutral compound 2 contains two anionic species of Ph⁻ and Pc˙³⁻ and the Sn^IV ion as the counter cation. Phenyl substituents are linked to the Sn^IV atoms by the Sn–C(Ph) bonds of 2.098(2) (1) and 2.105(2) Å (2) length. The dianionic Pc²⁻ macrocycle significantly deviates from planarity in 1 while Pc˙³⁻ is planar in 2. Salt 1 manifests only a weak impurity EPR signal. Compound 2 manifests an intense EPR signal with g = 2.0046 and a linewidth of 0.5 mT at 298 K due to the presence of Pc˙³⁻. Spins are weakly antiferromagnetically coupled in the π-stacking [SnPhPc˙³⁻]₂ dimers of 2 with a Weiss temperature of −3 K and the estimated magnetic exchange interaction J/k_B = −0.23 K.