Fullerene complexes with divalent metal dithiocarbamates: structures, magnetic properties, and photoconductivity

Abstract

A series of complexes of fullerenes C 60 and C 70 with metal dithiocarbamates {M II (R 2 dtc) 2 }•C m (m = 60 or 70) and metal dithiocarbamates coordinated to nitrogen con taining ligands (L), {M II (R 2 dtc) 2 ) x •L}•C 60 (x = 1 or 2), where M = Cu, Zn, Cd, Hg, Mn, or Fe, R = Me, Et, Pr n , Pr i , or Bu n , L is 1,4 diazabicyclo[2.2.2]octane (DABCO), N,N´ dimethylpiperazine, or hexamethylenetetramine, were synthesized. The shape of dithio carbamate molecules is sterically compatible with the spherical shape of C 60 , resulting in an efficient interaction between their π systems. The resulting compounds are characterized by a layered or three dimensional packing of the fullerene molecules. In the C 60 complexes, iron(II) and manganese(II) dithiocarbamates exist in the high spin states (S = 2 and 5/2). The magnetic susceptibility of {M II (Et 2 dtc) 2 } 2 •C m (M = Fe or Mn, m = 60 or 70) in the temperature range of 200-300 K is described by the Curie-Weiss law with Θ = -250 and -96 K and with maxima at 110 and 46 K, respectively, which is indicative of a strong antiferromagnetic spin coupling between M II . The Weiss constants for the [{M II (Et 2 dtc) 2 } 2 •DABCO]•C 60 •(DABCO) 2 com plexes (M = Fe or Mn) are 1.7 and 0.3 K, respectively. The magnetic moments of the complexes containing Fe and Mn dithiocarbamates slightly increase at temperatures below 50 and 35 K, respectively, which is evidence of the ferromagnetic spin coupling between M II in {M II (Et 2 dtc) 2 } 2 •DABCO. Single crystals of the complexes exhibit low dark conductivity (10 -10 -10 -11 S cm -1 ). The visible light irradiation of these crystals leads to an increase in the photocurrent by two-three orders of magnitude. The photogeneration of free charge carriers in the complexes occurs both due to the photoexcitation of metal dithiocarbamate (Cu II (Et 2 dtc) 2 ) and through the charge transfer from metal dithiocarbamate (M II (Et 2 dtc) 2 , M = Zn or Cd) to C 60 .

Coordination chemistry on carbon surfaces

“…fullerene and the corresponding metal dithiocarbamate (Fig. 16) [261,262]. According to optical and electron paramagnetic resonance (EPR) spectroscopy these species have a neutral ground state.…”

Crystal structure and Raman spectra of molecular complex [{Cd(Et2dtc)}2• DABCO]• C60• (DABCO)2 at high pressure

“…The crystals of the donor-acceptor complex |big[{Cd(Et 2 dtc)} 2 ·DABCO ·C 60 ·(DABCO) 2 were synthesized as described in [13]. The structural data were obtained for the single crystals at pressures up to 3 GPa using DAC and a four-circle Oxford Diffraction Gemini-R diffractometer equipped with two-dimensional CCD.…”

Pressure-assisted photopolymerization in the molecular donor-acceptor fullerene complex {Cd(dedtc)2}2•C60

“…Samples of the donor-acceptor complex {Cd(dedtc) 2 } 2 ·C 60 were obtained by evaporation of a solution containing fullerene acceptors and cadmium diethyldithiocarbamate donors by the method described in [18]. The XRD data show that the {Cd(dedtc) 2 } 2 ·C 60 complex acquires a monoclinic structure, space group P 2 1 /c with unit cell parameters a = 16.368(3), b = 17.056(2), c = 10.6650(15)Å, β = 100.058 (14) • and V = 2931.63Å 3 [7].…”