Synthesis, Crystal Structures, Magnetic Properties and Photoconductivity of C60 and C70 Complexes with Metal Dialkyldithiocarbamates M(R2dtc)x, where M = CuII, CuI, AgI, ZnII, CdII, HgII, MnII, NiII, and PtII; R = Me, Et, and nPr

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Abstract

New complexes of fullerenes C60 and C70 with metal dialkyldithiocarbamates, [M(R2dtc)x]·[C60(70)]·[Solvent], R = Et [M = CuII (C60, 1; C70, 2), CuI (C60, 3; C70, 4), AgI (C60, 5), ZnII (C60, 6), CdII (C60, 7; C70, 8), HgII (C60, 9), MnII (C70, 10)], R = Et and Me [M = CuII (C60, 11), and ZnII (C60, 12)], and R = nPr [M = CuII (C60, 13), NiII (C60, 14), and PtII (C60, 15)] were obtained. M(R2dtc)x efficiently cocrystallized with fullerene molecules as tetrahedral monomers (6, 12), dimers (1, 7, 11), and tetramers (3, 4). Fullerene molecules form closely packed hexagonal and square layers in 1, 7, and 11, hexagonal and tetragonal 3D structures in 6 and 12, and island motifs in 3 and 4. Complexes 115 have a neutral ground state. However, the formation of the complexes with fullerenes changes the environment of paramagnetic CuII and MnII. The EPR spectra of 1, 2, 11, and 13 are essentially modified relative to those of pristine Cu(R2dtc)2 because of a weak coordination of CuII to fullerene and a flattening of the central (NCS2)2Cu fragments. Complex 10 shows a spectrum exhibiting features from 50 to 600 mT and manifests strong antiferromagnetic coupling of spins with a Weiss temperature of –96 K and the maximum of magnetic susceptibility at 46 K. Such magnetic behavior can be explained by the formation of [Mn(Et2dtc)2]2 dimers in 10. The illumination of the crystals of 1, 2, and 7 by white light results in up to a 103 increase in photocurrent. The photoconductivity spectra have maxima at 470, 450–650, and 660 nm for 1, 2, and 7, respectively. Photogeneration of free charge carriers is realized by photoexcitation of Cu(Et2dtc)2 in 1 and 2, and by charge transfer from Cd(Et2dtc)2 to C60 molecules in 7. The decrease of photocurrent in 1 and 7 in a weak magnetic field with B0 < 0.5 T was found. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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