Formation of μ2-hydroxo-bonded (MgPc)2OH− assemblies and (C60−)2 dimers in ionic fullerene {(MgPc)2OH−}2·(C60−)2·(cation+)4 complexes

Abstract

Ionic complexes containing μ²-hydroxo-bonded (MgPc)₂OH⁻ phthalocyanine assemblies and C₆₀⁻ anions: {(MgPc)₂OH⁻}₂·(C₆₀⁻)₂·(PMDAE⁺)₄·(C₆H₅CN)₄ (1); {(MgPc)₂OH⁻}₂·(C₆₀⁻)₂·(TMP⁺)₄·(C₆H₅CN)₃·(C₆H₄Cl₂)_2.5 (2) (where PMDAE⁺ is the cation of N,N,N′,N′,N′-pentamethyldiaminoethane and TMP⁺ is the N,N′N′-trimethylpiperazinium cation) have been obtained as single crystals. The ionic ground state of the complexes is justified by the EPR spectra and the spectra in the IR and NIR ranges. The C₆₀˙⁻ radical anions are dimerized both in 1 and 2 in the 240–220 K range. Dimerization is accompanied by the reversible transition of the complexes from paramagnetic to diamagnetic state. MgPc forms unusual (MgPc)₂OH⁻ assemblies, in which the hydroxo-anion coordinates to two MgPc molecules by a μ²-fashion. The length of the Mg–O bonds is 1.936–1.955(2) Å, the Mg–O–Mg angle is 133.37–135.27(4)° and the displacement of the Mg atoms out of the mean 24-atom phthalocyanine plane is 0.77–0.86 Å. The packing of spherical fullerene and planar phthalocyanine molecules is attained in a crystal by the insertion of fullerenes between phenylene groups of phthalocyanines. It has been shown that metal phthalocyanines in ionic complexes with C₆₀ form M^IIPc·(L⁻) assemblies, whereas metalloporphyrins form M^IIporphyrin·(C⁺) assemblies.