Coordination of fullerene C60 and benzonitrile to iron(ii) tetraphenylporphyrin in the FeIITPP·C60·(C6H4Cl2)2·(C6H14)0.5 and FeIITPP·(C6H5CN)2 complexes

Abstract

The fullerene C₆₀ complex with iron(II) tetraphenylporphyrin Fe^IITPP·C₆₀·(C₆H₄Cl₂)₂·(C₆H₁₄) _0.5 (1) has been obtained as single crystals. IR- and EPR measurements have shown no noticeable charge transfer between Fe^IITPP and C₆₀ in 1. The crystal structure of 1 solved at 150(2) K contains chains of alternating Fe^IITPP and C₆₀ molecules. C₆₀ weakly coordinates to Fe^IITPP with the Fe^II⋯C(C₆₀) distances of 2.498(3)–2.502(3) Å. As a result, the Fe^II atoms displace by ± 0.153 and ± 0.188 Å out of the 24-atom porphyrin plane with equal probability (for two crystallographically independent Fe^IITPP). The Fe^II atom environment in 1 is closer to a five-coordinated one since four strong Fe^II-N(TPP) and one weak Fe^II–C(C₆₀) bonds are formed. Geometry of Fe^IITPP in the six-coordinated Fe^IITPP·(C₆H₅CN)₂ (2) complex obtained as single crystals is similar to that of Fe^IITPP in 1. However, the Fe^II atoms are positioned in 2 exactly in the porphyrin plane. Benzonitrile is unusually strongly bound to Fe^IITPP with the Fe^II–N(C₆H₅CN) bond length of 1.933(1) Å. The averaged length of the Fe^II–N(TPP) bonds of 2.000(2)–2.003(2) Å in 1 and 2.001(1) Å in 2 and moderate expansion of the porphyrin core indicates a low-spin state of Fe^IITPP in both complexes.