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Supramolecular Approach to the Synthesis of [60]Fullerene−Metal Dithiocarbamate Complexes, {(MII(R2dtc)2)x·L}·C60 (M = Zn, Cd, Hg, Fe, and Mn; x = 1 and 2). The Study of Magnetic Properties and Photoconductivity

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posted on 2008-04-02, 00:00 authored by Dmitri V. Konarev, Salavat S. Khasanov, Andrey Yu. Kovalevsky, Dmitri V. Lopatin, Vyacheslav V. Rodaev, Gunzi Saito, Bálint Náfrádi, László Forró, Rimma N. Lyubovskaya
Coordination assemblies formed by metal(II) dithiocarbamates MII(R2dtc)2 (M = Zn, Cd, Hg, Mn, and Fe; R = Me, Et, iPr, nPr, and nBu) and nitrogen-containing ligands (L = DABCO, DMP, and HMTA) are shown to be sterically well consistent with the spherical shape of fullerenes and are effectively cocrystallized with them to form complexes {(MII(R2dtc)2)x·L}·C60 (x = 1 and 2) with layered or three-dimensional (3D) packing of fullerene molecules (111). For the first time the molecular structures of the MII(R2dtc)2 assemblies in the complexes with C60 are presented (including those with M = Mn, Fe, and Hg). According to optical and electron paramagnetic resonance (EPR) spectroscopy 111 have a neutral ground state. Magnetic susceptibilities of {[MII(Et2dtc)2]2·DABCO}·C60·(DABCO)2 (M = Mn and Fe) follow the Curie–Weiss law in the 50–300 K range with the Weiss constants Θ = 0.35 and 1.70 K, respectively. Magnetic moments of the complexes equal to 8.23 and 6.88 μB at 300 K correspond to the high-spin state of the MnII (S = 5/2) and FeII (S = 2) ions. The increase of μeff observed below 35 and 50 K up to 8.5 μB (at 3 K) and 7.4 μB (at 6 K) indicates the manifestation of short-range ferromagnetic interactions between MII spins in the isolated [MII(Et2dtc)2]2·DABCO dimers. Under illumination by white light, the complexes show up to 102 times increase of photocurrent. The main contribution to the generation of free charge carriers is provided by direct charge transfer from {MII(R2dtc)2}2·L to C60. It was found that photocurrent increases in magnetic field with induction B < 1 T.