Ionic multi-component complexes containing TDAE˙+and C60˙−radical ions and neutral D1molecules: D1·TDAE·C60

Abstract

New ionic complexes containing TDAE˙+ and C60˙− radical ions and neutral molecules: (TBPDA)2·TDAE·C60 (1); CTV·TDAE·C60 (2); and CoIITPP·TDAE·C60 (3) (TDAE: tetrakis(dimethylamino)ethylene; TBPDA: N,N,N′,N′-tetrabenzyl-p-phenylenediamine; CTV: cyclotriveratrylene and CoIITPP: tetraphenylporphyrinate cobalt (II)) were obtained as single crystals. The presence of TDAE˙+, C60˙− and neutral donors in 1–3 was proved by optical absorption spectra in the IR and UV-vis-NIR ranges. In the crystal structure of 1 studied by single crystal X-ray diffraction, TDAE˙+ and C60˙− are spatially separated by bulky TBPDA molecules. Magnetic susceptibilities of 1 and 2 follow the Curie–Weiss law with the negative Weiss temperatures (−2.3 and −2.0 K) and their magnetic moments decrease below 60 and 15 K, respectively. The EPR signals from 1 and 2 at the same temperatures are split into two components, which shift in the opposite directions to lower and higher fields with the temperature decrease. This phenomenon is explained by the formation of field-induced short-range magnetically ordered clusters. CoIITPP and C60˙− form diamagnetic σ-bonded (CoIITPP·C60−) anions in 3 in the 1.9–190 K range. This allows one to observe the EPR signal from the isolated TDAE˙+ radical cations (g = 2.0031 and halfwidth = ΔH = 3.22 mT at 4 K). Above 190 K the magnetic moment of 3 increases and the EPR signal is essentially broadened and shifted to a lager g-factor (g = 2.0194, ΔH = 24.2 mT at 290 K). This is attributed to the dissociation of the σ-bonded diamagnetic (CoIITPP·C60−) anions to non-bonded paramagnetic CoIITPP and C60˙− components.