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

Abstract

Coordination assemblies formed by metal(II) dithiocarbamates M II (R 2 dtc) 2 (M = Zn, Cd, Hg, Mn, and Fe; R = Me, Et, i Pr, n Pr, and n Bu) 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 {(M II (R 2 dtc) 2 ) x ·L}·C 60 ( x = 1 and 2) with layered or three-dimensional (3D) packing of fullerene molecules ( 1 − 11 ). For the first time the molecular structures of the M II (R 2 dtc) 2 assemblies in the complexes with C 60 are presented (including those with M = Mn, Fe, and Hg). According to optical and electron paramagnetic resonance (EPR) spectroscopy 1 − 11 have a neutral ground state. Magnetic susceptibilities of {[M II (Et 2 dtc) 2 ] 2 ·DABCO}·C 60 ·(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 μ B at 300 K correspond to the high-spin state of the Mn II ( S = 5/2) and Fe II ( S = 2) ions. The increase of μ eff observed below 35 and 50 K up to 8.5 μ B (at 3 K) and 7.4 μ B (at 6 K) indicates the manifestation of short-range ferromagnetic interactions between M II spins in the isolated [M II (Et 2 dtc) 2 ] 2 ·DABCO dimers. Under illumination by white light, the complexes show up to 10 2 times increase of photocurrent. The main contribution to the generation of free charge carriers is provided by direct charge transfer from {M II (R 2 dtc) 2 } 2 ·L to C 60 . It was found that photocurrent increases in magnetic field with induction B < 1 T.