Neutral and ionic complexes of C60 with (ZnOEP)2·BPy coordination dimers

Abstract

Coordination (ZnOEP)₂·BPy dimers formed by zinc octaethylporphyrin and 4,4′-bipyridine co-crystallize with neutral C₆₀ and the (TDAE^˙+)·(C₆₀^˙–) ion-radical salt to form molecular and ionic multi-component complexes: {(ZnOEP)₂·BPy}·(C₆₀)₂·(CHCl₃)₂ (1) and (TDAE^˙+)₂·{(ZnOEP)₂·BPy}·(C₆₀^˙–)₂·(C₆H₆)_0.75·(C₆H₄Cl₂)_0.25 (2). The C₆₀ molecules are arranged in layers in 1 with the interfullerene center-to-center distances of 10.04–10.17 Å and in linear chains in 2 with the uniform interfullerene center-to-center distance of 10.61 Å. EPR measurements show exchange interaction between C₆₀^˙– and TDAE^˙+ ion-radicals in 2, which results in the appearance of one signal with g = 2.0027 and ΔH_pp = 19.8 G at 295 K rather than two signals from individual ion-radicals. The EPR signal from 2 is split into two components below 30 K and its integral intensity decreases below 9.6 K, which is evidence of antiferromagnetic interactions of spins.