title: Design, crystal structures and magnetic properties of anionic salts containing fullerene C₆₀ and indium(III) bromide phthalocyanine radical anions.
abstract: Two salts containing fullerene C60 and indium(III) bromide phthalocyanine (Pc) radical anions have been obtained as single crystals: (TBA(+))3(C60˙(-)){In(III)(Br)(Pc)˙(-)}(Br(-))·C6H4Cl2 (1) and (TEA(+))2(C60˙(-)){In(III)(Br)(Pc)˙(-)}·C6H4Cl2·C6H14 (2) where TBA(+) and TEA(+) are tetrabutyl- and tetraethylammonium cations, respectively. The presence of both radical anions is supported by spectra of 1 and 2 in the NIR and IR-ranges. The salts contain zigzag C60˙(-) chains with 10.136 and 10.383 Å center-to-center (ctc) distances in 1 and a uniform ctc distance of 10.186 Å in 2. In 1, the C60˙(-) radical anions are dimerized in the 180-140 K range to form singly bonded (C60(-))2 dimers, whereas they remain monomeric in 2. Effective packing of planar In(Br)(Pc)˙(-) and spherical C60˙(-) is attained by introducing fullerene spheres between the phenylene substituents of Pc allowing the formation of multiple van der Waals contacts between them. The effective magnetic moment of 1 at 300 K is 2.35μ(B), indicating a contribution of both C60˙(-) and In(Br)(Pc)˙(-) species having S = 1/2 spin state. There is strong antiferromagnetic coupling of spins between fullerenes in the chains and fullerenes and phthalocyanines in the monomeric phase of 1 with the Weiss temperature of -120 K in the 300-180 K range. The formation of diamagnetic (C60(-))2 dimers switches off magnetic coupling and magnetically isolates In(Br)(Pc)˙(-) (Weiss temperature is only -1 K in the 140-10 K range). Magnetic behavior of 2 is described by the Curie-Weiss law with weak ferromagnetic coupling of spins with Θ = +7.6 K in the 50-300 K range. Both salts manifest single Lorentzian EPR lines at room temperature with g = 1.9911 and a linewidth (ΔH) of 25.4 mT (1) and g = 1.9956 and ΔH = 7.5 mT (2) which can be attributed to both C60˙(-) and In(Br)(Pc)˙(-) species having strong exchange interaction. An asymmetric signal with the main component at g = 1.989-1.965 in the dimeric phase of 1 was attributed to the In(Br)(Pc)˙(-) radical anions.
authors.affiliation: Institute of Problems of Chemical Physics RAS, Chernogolovka, 142432, Russia. konarev@icp.ac.ru.
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Konarev
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Kuzmin
authors.forename: Salavat S
authors.initials: SS
authors.lastname: Khasanov
authors.forename: Akihiro
authors.initials: A
authors.lastname: Otsuka
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamochi
authors.forename: Gunzi
authors.initials: G
authors.lastname: Saito
authors.forename: Rimma N
authors.initials: RN
authors.lastname: Lyubovskaya